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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

(Mark One)

☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended September 30, 2025

OR

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

Commission file number 001-34375

PLUS THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

Delaware |  | 33-0827593
(State or other jurisdiction of incorporation or organization) |  | (I.R.S. Employer Identification No.)
2710 REED ROAD, SUITE 160, HOUSTON, TX |  | 77051
(Address of principal executive offices) |  | (Zip Code)

(737) 255-7194

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class | Trading Symbol(s) | Name of each exchange on which registered
Common Stock, par value $0.001 | PSTV | Nasdaq Capital Market

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See definitions of “large accelerated filer,” “accelerated filer”, “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large Accelerated Filer | ☐ |  | Accelerated Filer | ☐
Non-Accelerated Filer | ☒ |  | Smaller reporting company | ☒
|  |  | Emerging growth company | ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financing accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

As of October 29, 2025, there were 137,429,055 shares of the registrant’s common stock outstanding.

PLUS THERAPEUTICS, INC.

Table of Contents

|  |  |  | Page
PART I. |  | FINANCIAL INFORMATION |  |
|  | Item 1. |  | Consolidated Financial Statements (Unaudited) |  | 4
|  |  |  | Condensed Consolidated Balance Sheets |  | 4
|  |  |  | Condensed Consolidated Statements of Operations |  | 5
|  |  |  | Condensed Consolidated Statements of Stockholders’ Equity/(Deficit) |  | 6
|  |  |  | Condensed Consolidated Statements of Cash Flows |  | 7
|  |  |  | Notes to Condensed Consolidated Financial Statements |  | 8
|  | Item 2. |  | Management’s Discussion and Analysis of Financial Condition and Results of Operations |  | 25
|  | Item 3. |  | Quantitative and Qualitative Disclosures about Market Risk |  | 37
|  | Item 4. |  | Controls and Procedures |  | 37
PART II. |  | OTHER INFORMATION |  |
|  | Item 1. |  | Legal Proceedings |  | 37
|  | Item 1A. |  | Risk Factors |  | 37
|  | Item 2. |  | Unregistered Sales of Equity Securities and Use of Proceeds |  | 39
|  | Item 6. |  | Exhibits |  | 41

2

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This Quarterly Report on Form 10-Q (this “Quarterly Report”) and the exhibits incorporated herein by reference contain “forward-looking statements” which are made pursuant to the safe harbor provisions of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Statements other than statements of historical fact constitute “forward-looking statements.” These forward-looking statements do not constitute guarantees of future performance. These forward-looking statements may be identified by terms such as “intend,” “expect,” “project,” “believe,” “anticipate,” “initiate,” “will,” “should,” “would,” “could,” “may,” “designed,” “potential,” “evaluate,” “hypothesize,” “plan,” “progressing,” “proceeding,” “exploring,” “opportunity,” “hopes,” “suggest,” and similar expressions, or the negative of such expressions. Such statements are based upon certain assumptions and assessments made by our management in light of their experience and their perception of historical trends, current conditions, expected future developments and other factors they believe to be appropriate.

These statements include, without limitation, statements about our anticipated expenditures, including research and development, and general and administrative expenses; our intent or ability to regain and maintain compliance with Nasdaq listing standards; our strategic collaborations and license agreements, intellectual property, U.S. Food and Drug Administration and European Medicines Agency approvals and interactions and government regulation; the potential size of the market for our product candidates; our research and development efforts; results from our preclinical and clinical studies and the implications of such results regarding the efficacy or safety of our product candidates; the safety profile, pathways, and efficacy of our product candidates and formulations; anticipated advantages of our product candidates over other products available in the market and being developed; the populations that will most benefit from our product candidates and indications that will be pursued with each product candidate; anticipated progress in our current and future clinical trials; plans and strategies to create novel technologies; our IP strategy; competition; future development and/or expansion of our product candidates and therapies in our markets; sources of competition for any of our product candidates; our pipeline; our ability to generate product or development revenue and the sources of such revenue; our ability to effectively manage our gross profit margins; our ability to obtain and maintain regulatory approvals; expectations as to our future performance; our ability to satisfy our obligations under the terms of our capital raising transactions including registering shares issuable in such transactions; portions of the “Liquidity and Capital Resources” section of this Quarterly Report including our potential need for additional financing and the availability thereof; our ability to integrate into our business and operations, develop, fully utilize and monetize acquired assets; our ability to continue as a going concern; our ability to repay or refinance some or all of our outstanding indebtedness and our ability to raise capital in the future; our ability to transfer the drug and medical device product manufacturing to a contract drug and medical device manufacturing organization; the potential enhancement of our cash position through development, marketing, and licensing arrangements; our ability to timely and efficiently launch our CNSide® Cerebrospinal Fluid Tumor Cell Enumeration test (the “CNSide Test”); receipt of grant revenue; and a material security breach or cyber security attack affecting our operations and property.

Our actual results may differ, including materially, from those anticipated in these forward-looking statements as a result of various factors, including, but not limited to, the following: our ability to remain listed on Nasdaq; the early stage of our product candidates and therapies, the results of our research and development activities, including uncertainties relating to the clinical trials of our product candidates and therapies; our liquidity and capital resources and our ability to raise additional cash, the outcome of our partnering/licensing efforts, risks associated with laws or regulatory requirements applicable to us, market conditions, product performance, potential litigation, and competition within the radiotherapeutics, and more generally, oncological medicine fields, among others. The forward-looking statements included in this Quarterly Report are also subject to a number of additional material risks and uncertainties, including but not limited to the risks described under “Part I – Item 1A – Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2024, filed with the Securities and Exchange Commission (the “SEC”) on March 31, 2025 and under “Part II – Item 1A – Risk Factors” in this Quarterly Report. These risks and uncertainties could cause actual results to differ materially from expectations or those expressed in these forward-looking statements.

We caution you not to place undue reliance on the forward-looking statements contained in this Quarterly Report. These statements, like all statements in this report, speak only as of the date of this report (unless an earlier date is indicated) and the Company undertakes no obligation to update or revise the statements except as required by law. Such forward-looking statements are not guarantees of future performance.

3

Table of Contents

PART I. FINANC IAL INFORMATION

Item 1. Financ ial Statements

PLUS THERAPEUTICS, INC.

CONDEN SED CONSOLIDATED BALANCE SHEETS

(UNAUDITED)

(in thousands, except share and par value data)

|  | September 30, 2025 |  |  | December 31, 2024 |
Assets |  |  |  |  |  |
Current assets: |  |  |  |  |  |
Cash and cash equivalents |  | $ | 13,289 |  |  | $ | 76 |
Investments |  |  | 3,312 |  |  |  | 3,530 |
Grant receivable |  |  | — |  |  |  | 571 |
Other current assets |  |  | 985 |  |  |  | 1,082 |
Total current assets |  |  | 17,586 |  |  |  | 5,259 |
Property and equipment, net |  |  | 273 |  |  |  | 448 |
Operating lease right-of-use assets |  |  | 20 |  |  |  | 73 |
Goodwill |  |  | 372 |  |  |  | 372 |
Intangible assets, net |  |  | 374 |  |  |  | 469 |
Other assets |  |  | 45 |  |  |  | 12 |
Total assets |  | $ | 18,670 |  |  | $ | 6,633 |
Liabilities and Stockholders’ Equity (Deficit) |  |  |  |  |  |
Current liabilities: |  |  |  |  |  |
Accounts payable and accrued expenses |  | $ | 11,623 |  |  | $ | 11,288 |
Operating lease liability |  |  | 21 |  |  |  | 44 |
Deferred grant liability |  |  | 1,972 |  |  |  | 927 |
Line of credit |  |  | — |  |  |  | 3,292 |
Total current liabilities |  |  | 13,616 |  |  |  | 15,551 |
Noncurrent operating lease liability |  |  | — |  |  |  | 31 |
Total liabilities |  |  | 13,616 |  |  |  | 15,582 |
Commitments and contingencies (Note 8) |  |  |  |  |  |
Stockholders’ equity (deficit): |  |  |  |  |  |
Preferred stock, $0.001 par value; 5,000,000 shares authorized; 1,952 shares issued and outstanding as of September 30, 2025 and December 31, 2024, respectively |  |  | — |  |  |  | — |
Common stock, $0.001 par value; 2,000,000,000 shares authorized; 131,863,969 shares issued; and 131,605,544 shares outstanding as of September 30, 2025, and 100,000,00 shares authorized; 6,154,758 shares issued; and 5,896,333 shares outstanding as of December 31, 2024, respectively |  |  | 132 |  |  |  | 6 |
Treasury stock (at cost), 258,425 shares as of September 30, 2025 and December 31, 2024, respectively |  |  | (500 | ) |  |  | (500 | )
Additional paid-in capital |  |  | 515,574 |  |  |  | 485,024 |
Accumulated deficit |  |  | (510,152 | ) |  |  | (493,479 | )
Total stockholders’ equity (deficit) |  |  | 5,054 |  |  |  | (8,949 | )
Total liabilities and stockholders’ equity |  | $ | 18,670 |  |  | $ | 6,633 |

See Accompanying Notes to these Condensed Consolidated Financial Statements

4

Table of Contents

PLUS THERAPEUTICS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPE RATIONS

(UNAUDITED)

(in thousands, except share and per share data)

|  | For the Three Months Ended September 30, |  |  | For the Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Grant revenue |  | $ | 1,397 |  |  | $ | 1,456 |  |  | $ | 3,846 |  |  | $ | 4,412 |
Operating expenses: |  |  |  |  |  |  |  |  |  |  |  |
Research and development |  |  | 2,436 |  |  |  | 2,858 |  |  |  | 5,438 |  |  |  | 8,394 |
General and administrative |  |  | 3,443 |  |  |  | 2,397 |  |  |  | 7,964 |  |  |  | 6,813 |
Total operating expenses |  |  | 5,879 |  |  |  | 5,255 |  |  |  | 13,402 |  |  |  | 15,207 |
Operating loss |  |  | (4,482 | ) |  |  | (3,799 | ) |  |  | (9,556 | ) |  |  | (10,795 | )
Other income (expense): |  |  |  |  |  |  |  |  |  |  |  |
Interest income |  |  | 59 |  |  |  | 80 |  |  |  | 87 |  |  |  | 219 |
Interest expense |  |  | — |  |  |  | (61 | ) |  |  | (548 | ) |  |  | (122 | )
Financing expenses |  |  | — |  |  |  | — |  |  |  | (3,061 | ) |  |  | (3,545 | )
Warrant issuance costs |  |  | — |  |  |  | (54 | ) |  |  | (964 | ) |  |  | (486 | )
Change in fair value of derivative instruments |  |  | — |  |  |  | 960 |  |  |  | (2,631 | ) |  |  | 5,654 |
Total other income (expense) |  |  | 59 |  |  |  | 925 |  |  |  | (7,117 | ) |  |  | 1,720 |
Net loss |  | $ | (4,423 | ) |  | $ | (2,874 | ) |  | $ | (16,673 | ) |  | $ | (9,075 | )
Per share information |  |  |  |  |  |  |  |  |  |  |  |
Net loss per share of common stock – basic |  | $ | (0.04 | ) |  | $ | (0.37 | ) |  | $ | (0.29 | ) |  | $ | (1.46 | )
Weighted average number of shares of common stock outstanding – basic |  |  | 107,428,969 |  |  |  | 7,855,763 |  |  |  | 57,845,406 |  |  |  | 6,232,123 |
Net loss per share of common stock – diluted |  | $ | (0.04 | ) |  | $ | (0.37 | ) |  | $ | (0.29 | ) |  | $ | (1.67 | )
Weighted average number of shares of common stock outstanding – diluted |  |  | 107,428,969 |  |  |  | 7,855,763 |  |  |  | 57,845,406 |  |  |  | 8,452,338 |

See Accompanying Notes to these Condensed Consolidated Financial Statements

5

Table of Contents

PLUS THERAPEUTICS, INC.

CONDENSED CONSOLIDATED STATEME NTS OF STOCKHOLDERS’ EQUITY/(DEFICIT)

(UNAUDITED) (In thousands, except share data)

| Convertible |  |  |  |  |  |  |  |  |  |  |  |  |  |  | Additional |  |  |  |  |  | Total |
| preferred stock |  |  | Common stock |  |  | Treasury Stock |  |  | paid-in |  |  | Accumulated |  |  | stockholders’ |
| Shares |  |  |  | Amount |  |  | Shares |  |  | Amount |  |  | Shares |  |  | Amount |  |  | capital |  |  | deficit |  |  | (deficit)/equity |
Balance at December 31, 2023 |  | 1,952 |  |  | $ |  | — |  |  |  | 4,522,656 |  | $ |  | 5 |  |  |  | (78,559 | ) | $ |  | (126 | ) | $ |  | 479,274 |  | $ |  | (480,501 | ) | $ |  | (1,348 | )
Stock-based compensation |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 146 |  |  |  | — |  |  |  | 146 |
Purchase of treasury stock |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (179,866 | ) |  |  | (374 | ) |  |  | — |  |  |  | — |  |  |  | (374 | )
Net loss |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (3,261 | ) |  |  | (3,261 | )
Balance at March 31, 2024 |  | 1,952 |  |  | $ |  | — |  |  |  | 4,522,656 |  | $ |  | 5 |  |  |  | (258,425 | ) | $ |  | (500 | ) | $ |  | 479,420 |  | $ |  | (483,762 | ) | $ |  | (4,837 | )
Issuance of common stock |  | — |  |  |  |  | — |  |  |  | 1,439,988 |  |  |  | 1 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 1 |
Stock-based compensation |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 151 |  |  |  | — |  |  |  | 151 |
Net loss |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (2,940 | ) |  |  | (2,940 | )
Balance at June 30, 2024 |  | 1,952 |  |  | $ |  | — |  |  |  | 5,962,644 |  | $ |  | 6 |  |  |  | (258,425 | ) | $ |  | (500 | ) | $ |  | 479,571 |  | $ |  | (486,702 | ) | $ |  | (7,625 | )
Reclass of warrants to equity |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 5,200 |  |  |  | — |  |  |  | 5,200 |
Stock-based compensation |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 125 |  |  |  | — |  |  |  | 125 |
Exercise of pre-funded warrants |  | — |  |  |  |  | — |  |  |  | 192,114 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |
Net loss |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (2,874 | ) |  |  | (2,874 | )
Balance at September 30, 2024 |  | 1,952 |  |  | $ |  | — |  |  |  | 6,154,758 |  | $ |  | 6 |  |  |  | (258,425 | ) | $ |  | (500 | ) | $ |  | 484,896 |  | $ |  | (489,576 | ) | $ |  | (5,174 | )
Balance at December 31, 2024 |  | 1,952 |  |  | $ |  | — |  |  |  | 6,154,758 |  | $ |  | 6 |  |  |  | (258,425 | ) | $ |  | (500 | ) | $ |  | 485,024 |  | $ |  | (493,479 | ) | $ |  | (8,949 | )
Stock-based compensation |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 148 |  |  |  | — |  |  |  | 148 |
Exercise of pre-funded warrants |  | — |  |  |  |  | — |  |  |  | 6,535,731 |  |  |  | 7 |  |  |  | — |  |  |  | — |  |  |  | (7 | ) |  |  | — |  |  |  | — |
Exercise of Series B Warrants from May 2024 PIPE |  | — |  |  |  |  | — |  |  |  | 497,824 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 882 |  |  |  | — |  |  |  | 882 |
Exchange of warrants for notes payable |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (3,694 | ) |  |  | — |  |  |  | (3,694 | )
Issuance of common stock, pre-funded warrants and warrants for debt repayment |  | — |  |  |  |  | — |  |  |  | 4,069,738 |  |  |  | 4 |  |  |  | — |  |  |  | — |  |  |  | 5,369 |  |  |  | — |  |  |  | 5,373 |
Net loss |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (17,401 | ) |  |  | (17,401 | )
Balance at March 31, 2025 |  | 1,952 |  |  | $ |  | — |  |  |  | 17,258,051 |  | $ |  | 17 |  |  |  | (258,425 | ) | $ |  | (500 | ) | $ |  | 487,722 |  | $ |  | (510,880 | ) | $ |  | (23,641 | )
Stock-based compensation |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 152 |  |  |  | — |  |  |  | 152 |
Exercise or exchange of March 2025 Series A and B Warrants |  | — |  |  |  |  | — |  |  |  | 56,277,032 |  |  |  | 56 |  |  |  | — |  |  |  | — |  |  |  | 802 |  |  |  | — |  |  |  | 858 |
Exercise of pre-funded warrants |  | — |  |  |  |  | — |  |  |  | 9,016,349 |  |  |  | 9 |  |  |  | — |  |  |  | — |  |  |  | (9 | ) |  |  | — |  |  |  | — |
Cancellation of common stock |  | — |  |  |  |  | — |  |  |  | (300,000 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |
Issuance of common stock under Lincoln Park Purchase Agreement, net issuance costs |  | — |  |  |  |  | — |  |  |  | 10,187,000 |  |  |  | 10 |  |  |  | — |  |  |  | — |  |  |  | 2,736 |  |  |  | — |  |  |  | 2,746 |
Reclassification of 2025 Series B warrant liability to equity |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 10,967 |  |  |  | — |  |  |  | 10,967 |
Modification of warrants (Note 13) |  |  |  |  |  |  |  |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 6,801 |  |  |  | — |  |  |  | 6,801 |
Net income |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 5,151 |  |  |  | 5,151 |
Balance at June 30, 2025 |  | 1,952 |  |  | $ |  | — |  |  |  | 92,438,432 |  | $ |  | 92 |  |  |  | (258,425 | ) | $ |  | (500 | ) | $ |  | 509,171 |  | $ |  | (505,729 | ) | $ |  | 3,034 |
Stock-based compensation |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 527 |  |  |  | — |  |  |  | 527 |
Cancelled common stock |  | — |  |  |  |  | — |  |  |  | (3,472,740 | ) |  |  | (3 | ) |  |  | — |  |  |  | — |  |  |  | 3 |  |  |  | — |  |  |  | — |
Issuance of common stock under Lincoln Park Purchase Agreement, net issuance costs |  | — |  |  |  |  | — |  |  |  | 34,388,496 |  |  |  | 35 |  |  |  | — |  |  |  | — |  |  |  | 16,815 |  |  |  | — |  |  |  | 16,850 |
Investor fees pursuant to Support Letters (Note 13) |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (2,250 | ) |  |  | — |  |  |  | (2,250 | )
Exercise of March 2025 Series B Warrants |  | — |  |  |  |  | — |  |  |  | 741,840 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |
Exercise of pre-funded warrants |  | — |  |  |  |  | — |  |  |  | 7,767,941 |  |  |  | 8 |  |  |  | — |  |  |  | — |  |  |  | (8 | ) |  |  | — |  |  |  | — |
Liability to investors pursuant to Letter Agreement (Note 13) |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (8,684 | ) |  |  | — |  |  |  | (8,684 | )
Net loss |  | — |  |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (4,423 | ) |  |  | (4,423 | )
Balance at September 30, 2025 |  | 1,952 |  |  | $ |  | — |  |  |  | 131,863,969 |  | $ |  | 132 |  |  |  | (258,425 | ) | $ |  | (500 | ) | $ |  | 515,574 |  | $ |  | (510,152 | ) | $ |  | 5,054 |

See Accompanying Notes to these Condensed Consolidated Financial Statements

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PLUS THERAPEUTICS, INC.

CONDENSED CONSOLIDATED S TATEMENTS OF CASH FLOWS

(UNAUDITED)

(In thousands)

|  | For the Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |
Cash flows used in operating activities: |  |  |  |  |  |
Net loss |  | $ | (16,673 | ) |  | $ | (9,075 | )
Adjustments to reconcile net loss to net cash used in operating activities: |  |  |  |  |  |
Depreciation and amortization |  |  | 300 |  |  |  | 524 |
Amortization of deferred financing costs and debt discount |  |  | — |  |  |  | 20 |
Stock-based compensation expense |  |  | 827 |  |  |  | 422 |
Noncash financing expenses |  |  | 3,061 |  |  |  | 3,545 |
Change in fair value of derivative instruments |  |  | 2,631 |  |  |  | (5,654 | )
Accretion of discount on short-term investments |  |  | (19 | ) |  |  | (70 | )
Reduction in the carrying amount of operating lease right-of-use assets |  |  | 53 |  |  |  | 96 |
Gain on sale of assets |  |  | (16 | ) |  |  | — |
Increases (decreases) in cash caused by changes in operating assets and liabilities: |  |  |  |  |  |
Other assets |  |  | 635 |  |  |  | 704 |
Accounts payable and accrued expenses |  |  | (6,308 | ) |  |  | 1,326 |
Change in operating lease liabilities |  |  | (54 | ) |  |  | (97 | )
Deferred grant liability |  |  | 1,045 |  |  |  | (1,084 | )
Net cash used in operating activities |  |  | (14,518 | ) |  |  | (9,343 | )
Cash flows used in investing activities: |  |  |  |  |  |
Purchases of property and equipment |  |  | (37 | ) |  |  | (135 | )
Proceeds from sale of property and equipment |  |  | 30 |  |  |  | — |
Purchase of short-term investments |  |  | (11,068 | ) |  |  | (7,145 | )
Redemption of short-term investments |  |  | 11,305 |  |  |  | 3,650 |
Purchase of intangible assets |  |  | (7 | ) |  |  | (545 | )
Net cash provided by (used in) investing activities |  |  | 223 |  |  |  | (4,175 | )
Cash flows provided by financing activities: |  |  |  |  |  |
Principal payments of term loan obligation |  |  | — |  |  |  | (3,996 | )
Proceeds from credit facility |  |  | — |  |  |  | 3,292 |
Repayment of credit facility |  |  | (3,292 | ) |  |  | — |
Payment of financing costs |  |  | (2,250 | ) |  |  | — |
Proceeds from issuance of notes payable and warrants |  |  | 3,738 |  |  |  | — |
Repayment of notes payable |  |  | (3,703 | ) |  |  | — |
Purchase of treasury stock |  |  | — |  |  |  | (374 | )
Proceeds from sale of common stock, pre-funded warrants and warrants |  |  | 15,927 |  |  |  | 7,265 |
Proceeds from sale of common stock under Lincoln Park Purchase Agreement |  |  | 19,612 |  |  |  | — |
Payment to investors pursuant to Letter Agreement (Note 13) |  |  | (2,293 | ) |  |  | — |
Offering costs for sale of common stock |  |  | (231 | ) |  |  | — |
Net cash provided by financing activities |  |  | 27,508 |  |  |  | 6,187 |
Net increase (decrease) in cash and cash equivalents |  |  | 13,213 |  |  |  | (7,331 | )
Cash and cash equivalents at beginning of period |  |  | 76 |  |  |  | 8,554 |
Cash and cash equivalents at end of period |  | $ | 13,289 |  |  | $ | 1,223 |
Supplemental disclosure of cash flows information: |  |  |  |  |  |
Cash paid during period for: |  |  |  |  |  |
Interest |  | $ | 539 |  |  | $ | 32 |
Supplemental schedule of non-cash investing and financing activities: |  |  |  |  |  |
Unpaid liability to investors pursuant to Letter Agreement (Note 13) |  | $ | 6,391 |  |  | $ | — |
Exchange of warrants for notes payable |  | $ | 3,694 |  |  | $ | — |
Redemption of notes by issuance of common stock, pre-funded warrants and warrants |  | $ | 3,512 |  |  | $ | — |
Unpaid offering cost |  | $ | 252 |  |  | $ | — |

See Accompanying Notes to these Condensed Consolidated Financial Statements

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PLUS TH ERAPEUTICS, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

September 30, 2025

(UNAUDITED)

1. Organization and Basis of Presentation

Description of Business

Plus Therapeutics, Inc. (the “Company”) is a clinical-stage pharmaceutical company focused on the development, manufacture and commercialization of complex and innovative treatments for patients battling cancer and other life-threatening diseases. CNSide Diagnostics, LLC is a wholly owned subsidiary of Plus Therapeutics, Inc. that develops and commercializes proprietary laboratory-developed tests, such as the CNSide™ Test, designed to identify tumor cells that have metastasized to the central nervous system in patients with carcinomas and melanomas.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements for the three and nine months ended September 30, 2025 and 2024 have been prepared in accordance with accounting principles generally accepted in the United States of America ("US GAAP") for interim financial information. Accordingly, they do not include all of the information and footnotes required by US GAAP for annual financial statements. The condensed consolidated balance sheet at December 31, 2024 has been derived from the audited consolidated financial statements at December 31, 2024, but does not include all of the information and footnotes required by US GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the financial position and results of operations of the Company have been included. Operating results for the three and nine months ended September 30, 2025 are not necessarily indicative of the results that may be expected for the year ending December 31, 2025.

2. Summary of Significant Accounting Policies

Significant Accounting Policies

The Company’s significant accounting policies are disclosed in its Annual Report on Form 10-K for the year ended December 31, 2024 filed with the SEC and have not materially changed during the nine months ended September 30, 2025. The Company believes that the disclosures provided here are adequate to make the information presented not misleading when these unaudited condensed consolidated financial statements are read in conjunction with the audited consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024, filed with the Securities and Exchange Commission on March 31, 2025.

Use of Estimates

The preparation of financial statements in conformity with US GAAP requires management to make estimates and assumptions affecting the financial statements and the accompanying notes. The Company’s most significant estimates and critical accounting policies involve estimating the fair value of its derivative instruments, reviewing assets for impairment and determining the assumptions used in measuring stock-based compensation expense.

Grant Revenue Recognition

In applying the provisions of Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers (“ASC 606”), the Company has determined that government grants are out of the scope of ASC 606 because the funding entities do not meet the definition of a “customer”, as defined by ASC 606, as the Company does not consider there to be a transfer of control of goods or services. With respect to each grant, the Company determines if it has a collaboration in accordance with ASC Topic 808, Collaborative Arrangements (“ASC 808”). For grants outside the scope of ASC 808, the Company applies International Accounting Standards No. 20 ("IAS 20"), Accounting for Government Grants and Disclosure of Government Assistance, by analogy, and revenue is recognized when the Company incurs expenses related to the grant for the amount the Company is entitled to under the provisions of the contract.

The Company also considers the guidance in ASC Topic 730, Research and Development, which requires an assessment, at the inception of each grant, of whether each grant agreement is a liability. If the Company is obligated to repay funds received regardless of the outcome of the related research and development activities, then the Company is required to estimate and recognize that liability. Alternatively, if the Company is not required to repay the funds, then payments received are recorded as revenue or contra-expense as the expenses are incurred.

Deferred grant liability represents grant funds received or receivable for which the allowable expenses have not yet been incurred as of the balance sheet date. Grant receivable represents grant funds not yet received for which the allowable expenses have been incurred as of the balance sheet date.

Warrants

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Warrants are accounted for as either derivative liabilities or as equity instruments depending on the specific terms of the agreement in accordance with applicable accounting guidance provided in ASC Topic 815, Derivatives and Hedging. Equity-classified instruments are recorded in additional paid-in capital at issuance and are not subject to remeasurement. Liability-classified warrants are recorded at fair value at each reporting period with any change in fair value recognized as a component of change in fair value of derivative liabilities in the condensed consolidated statements of operations. The Company periodically evaluates changes in facts and circumstances that could impact the classification of warrants.

Available-for-Sale Securities

The Company’s available-for-sale securities consist of U.S. government and agency securities and bonds. Securities with maturities from the date of purchase of less than three months are included in cash equivalents. The Company classifies its marketable securities as available-for-sale and records such assets at estimated fair value in the condensed consolidated balance sheets, with unrealized gains and losses, if any, reported as a component of other comprehensive income (loss) and as a separate component of stockholders’ equity. Realized gains and losses are calculated on the specific identification method and recorded as interest income (expense). At each balance sheet date, the Company assesses available-for-sale securities in an unrealized loss position to determine whether the decline in fair value below amortized cost is a result of credit losses or other factors, whether the Company expects to recover the amortized cost of the security, the Company’s intent to sell and if it is more likely than not that the Company will be required to sell the securities before the recovery of amortized cost. The Company records changes in allowance for expected credit loss in other income (expense). There has been no allowance for expected credit losses recorded during any of the periods presented.

Any premium arising at purchase is amortized to the earliest call date and any discount arising at purchase is accreted to maturity. Accretion of discounts are recorded in interest income in the condensed consolidated statements of operations.

Recently Issued Accounting Pronouncements

In December 2023, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (ASU) No. 2023-09 Income Taxes (Topic 740): Improvements to Income Tax Disclosure. This ASU includes amendments that further enhance income tax disclosures, primarily through standardization and disaggregation of rate reconciliation categories and income taxes paid by jurisdiction. The ASU is effective for years beginning after December 15, 2024, but early adoption is permitted. This ASU should be applied on a prospective basis, although retrospective application is permitted. The Company adopted this ASU as of January 1, 2025 which did not have a material impact on the Company’s consolidated financial statements and related disclosures.

In November 2024, the FASB issued ASU 2024-03 Income Statement (Topic 220): Reporting Comprehensive Income - Expense Disaggregation Disclosures, which requires an entity to disclose on an annual and interim basis, disaggregated information about specific income statement expense categories. The guidance should be applied prospectively with the option to apply the standard retrospectively. The standard becomes effective for the annual period starting on January 1, 2027 and interim periods starting on January 1, 2028. The Company is in the process of analyzing the impact that the adoption of ASU 2024-03 will have on its disclosures.

3. Liquidity and Going Concern

The Company incurred a net loss of $16.7 million for the nine months ended September 30, 2025. The Company had an accumulated deficit of $510.2 million as of September 30, 2025. Additionally, the Company used net cash of $14.5 million to fund its operating activities for the nine months ended September 30, 2025.

To date, the Company’s operating losses have been funded primarily from outside sources of invested capital from issuance of its common stock, preferred stock, convertible notes and warrants, proceeds from its term loan, line of credit and grant funding. However, the Company has had, and will continue to have, an ongoing need to raise additional cash from outside sources to fund its future clinical development programs, launch the CNSide Test, and fund other operations. There can be no assurance that the Company will be able to continue to raise additional capital in the future. The Company’s inability to raise additional cash would have a material and adverse impact on its operations. These factors raise substantial doubt about the Company’s ability to continue as a going concern.

As disclosed in more detail in Note 13, the Company has entered into various financing agreements and raised capital by issuing convertible notes, its common stock, preferred stock and warrants to purchase its common stock.

Nasdaq Listing Compliance

On March 8, 2024, the Company received a written notice (the “Notice”) from the Listing Qualifications staff (the “Staff”) of The Nasdaq Stock Market LLC (the “Nasdaq)”), notifying the Company that it no longer complied with the requirement under Nasdaq Listing Rule 5550(b)(1) to maintain a minimum of $2.5 million in stockholders’ equity (the “Minimum Stockholders’ Equity Requirement”) for continued listing on The Nasdaq Capital Market or the alternative requirements of having a market value of listed securities of $35 million or net income from continuing operations of $500,000 in the most recently completed fiscal year or two of the last three most recently completed fiscal years.

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On September 5, 2024, Nasdaq notified the Company that it had not regained compliance with Nasdaq Listing Rule 5550(b)(1). The Company requested a hearing before the Nasdaq hearing panel, and on October 30, 2024, the Company received a decision from the panel, notifying the Company that it had until March 4, 2025, to demonstrate compliance with the Minimum Stockholders’ Equity Requirement.

On March 7, 2025, the Company received notification from Nasdaq that it had regained compliance with the Minimum Stockholders’ Equity Requirement.

Pursuant to Nasdaq Listing Rule 5815(d)(4)(B), the Company is subject to a Mandatory Panel Monitor until March 7, 2026. If the Staff finds the Company again out of compliance with the Minimum Stockholders’ Equity Requirement before that date, the Company would not be permitted to provide the Staff with a plan of compliance with respect to that deficiency and the Staff would not be permitted to grant additional time for the Company to regain compliance with respect to that deficiency, nor would the Company be afforded an applicable cure or compliance period. Instead, the Staff would issue a “Delist Determination Letter” and the Company would have an opportunity to request a Nasdaq hearing panel regarding its continued listing.

Furthermore, on May 16, 2025, the Company received notice from Nasdaq that, because the closing bid price for the Company’s common stock had fallen below $1.00 per share for 30 consecutive business days, the Company no longer complied with the minimum bid price requirement pursuant to Nasdaq Listing Rule 5550(a)(2) (the “Minimum Bid Requirement”).

Nasdaq’s Minimum Bid Requirement notice has no immediate effect on the listing or trading of the Company’s common stock. Pursuant to Nasdaq Listing Rule 5810(c)(3)(A), the Company is provided an initial compliance period of 180 calendar days, or until November 12, 2025, to regain compliance with the Minimum Bid Requirement. To regain compliance, the closing bid price of the Company’s common stock must meet or exceed $1.00 per share for a minimum of 10 consecutive business days prior to November 12, 2025.

If the Company does not achieve compliance with the Minimum Bid Requirement by November 12, 2025, the Company may be eligible for an additional 180 calendar days to regain compliance. To qualify, the Company would be required to meet the continued listing requirement for market value of publicly held shares and all other Nasdaq initial listing standards, with the exception of the Minimum Bid Requirement, and provide written notice of its intention to cure the minimum bid price deficiency during the second compliance period by effecting a reverse stock split if necessary. If the Staff determines that the Company will not be able to cure the deficiency, or if the Company is otherwise not eligible for such additional compliance period, Nasdaq will provide notice that the Company’s common stock will be subject to delisting. In the event the Company receives notice that its common stock is being delisted, Nasdaq rules permit the Company to appeal any delisting determination by the Staff.

On May 2, 2025, the stockholders granted discretionary authority to the Company’s board of directors to (i) amend the Company’s Certificate of Incorporation to combine outstanding shares of the Company’s common stock into a lesser number of outstanding shares, or a “reverse stock split,” at a specific ratio within a range of one-for twenty five (1-for-25) to a maximum of one-for-two hundred fifty (1-for-250), with the exact ratio to be determined by the board of directors in its sole discretion; and (ii) effect the reverse stock split, if at all, within twelve (12) months of the date the proposal is approved by stockholders.

In addition, on August 7, 2025, the stockholders granted discretionary authority to the Company’s board of directors to (i) amend the Company’s Certificate of Incorporation to combine outstanding shares of the Company’s common stock into a lesser number of outstanding shares, or a “reverse stock split,” at a specific ratio within a range of one-for two (1-for-2) to a maximum of one-for-two hundred fifty (1-for-250), with the exact ratio to be determined by the board of directors in its sole discretion; and (ii) effect the reverse stock split, if at all, within twelve (12) months of the date the proposal is approved by stockholders.

On June 3, 2025, the Staff notified the Company that it was not in compliance with the Minimum Stockholders’ Equity Requirement (the “June 3 Letter”). The Company reported stockholders’ equity (deficit) of ($23,641,000) in its Quarterly Report on Form 10-Q for the period ended March 31, 2025, and, as a result, did not satisfy the Minimum Stockholders’ Equity Requirement pursuant to Listing Rule 5550(b)(1). As a result, the Staff determined to delist the Company’s securities from Nasdaq, unless the Company timely requests an appeal of the Staff’s determination to a Hearings Panel (the “Panel”), pursuant to the procedures set forth in the Nasdaq Listing Rule 5800 Series. The Company must request a hearing no later than 4:00 p.m. Eastern Time on June 10, 2025. The Company timely requested a hearing, which hearing took place as scheduled on July 15, 2025.

On July 22, 2025, the Panel issued a decision (the “July 2025 Decision”) granting the Company’s request for continued listing on Nasdaq, subject to the Company demonstrating compliance with (1) the Minimum Stockholders’ Equity Requirement pursuant to Listing Rule 5550 (b)(1) by August 14, 2025 by filing a timely public disclosure describing the transactions undertaken by the Company to achieve compliance and demonstrate long-term compliance of the Minimum Stockholders’ Equity Requirement, and by providing an indication of its equity following those transactions, with the option by including in the public filing a balance sheet not older than 60 days with pro forma adjustments for any significant transactions or events occurring on or before the report date; and (2) the Minimum Bid Requirement by September 8, 2025.

On August 22, 2025, the Company received a letter (the “August 2025 Letter”) from Nasdaq confirming its compliance with Nasdaq Listing Rule 5550(b). Specifically, the August 2025 Letter confirmed that the Company was in compliance with both (1) the Market Value of Listing Securities standard under 5550(b)(2), which requires certain companies to maintain a market value of listed securities of at least $35 million as well as compliance with (2) the alternative stockholders’ equity threshold under 5550(b)(1) or the Minimum Stockholders’ Equity Requirement. Accordingly, the Company satisfied two alternative criteria under

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Nasdaq Listing Rule 5550.

As a result of such compliance, Nasdaq permitted the Company the remainder of the previously announced grace period to regain compliance with the $1.00 bid price rule under Nasdaq Listing Rule 5550(a)(2), through November 12, 2025. Nasdaq previously required that the Company remedy the bid price deficiency by September 8, 2025, a deadline that no longer applies.

The August 2025 Letter also provided that, solely with respect to the Equity Standard, the Company remains subject to a one-year panel monitoring period, through August 22, 2026. If, within that one-year monitoring period, the Staff determines that the Company no longer satisfies the Equity Standard (and the Company is not then in compliance with one of the alternative standards under Rule 5550(b)), the Company will not be permitted to provide the Staff with a plan of compliance and the Staff is not permitted to grant additional time to regain compliance with the Equity Standard nor will the Company be afforded an applicable cure or compliance period. Instead, the Staff will issue a delist determination letter, and the Company will have an opportunity to request a new hearing before the Nasdaq Hearings Panel, which request would stay any further action by the Staff pending the ultimate outcome of the hearing.

The Company continues to seek additional capital from other financing alternatives and other sources in order to ensure adequate funding is available to allow the Company to continue research and product development activities. If sufficient capital is not raised, the Company will at a minimum need to significantly reduce or curtail its research and development and other operations, and this would negatively affect its ability to achieve corporate growth goals.

Should the Company fail to raise additional cash, it would have a material adverse impact on its operations.

The accompanying condensed consolidated financial statements have been prepared assuming the Company will continue to operate as a going concern, which contemplates the realization of assets and settlement of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classifications of liabilities that may result from uncertainty related to its ability to continue as a going concern.

4. Fair Value Measurements

Fair value measurements are market-based measurements, not entity-specific measurements. Therefore, fair value measurements are determined based on the assumptions that market participants would use in pricing the asset or liability. The Company follows a three-level hierarchy to prioritize the inputs used in the valuation techniques to derive fair values. The basis for fair value measurements for each level within the hierarchy is described below:

•
Level 1: Quoted prices in active markets for identical assets or liabilities.

•
Level 2: Quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs are observable in active markets.

•
Level 3: Valuations derived from valuation techniques in which one or more significant inputs are unobservable in active markets.

Assets recorded at fair value

The Company has investments in money market accounts which are included in cash and cash equivalents and investments, respectively, on the condensed consolidated balance sheets. Money market accounts are considered Level 1 measurements within the fair value hierarchy since money market account fair values are known and observable through daily published floating net asset values.

The following table summarizes the Company’s fair value hierarchy for its financial assets measured at fair value on a recurring basis as of September 30, 2025 and December 31, 2024, respectively (in thousands):

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| Fair Value Measurements Using |
September 30, 2025 | Fair Value |  | Level 1 |  | Level 2 |  | Level 3 |
Cash equivalents |  |  |  |  |  |  |  |
Money market | $ | 15 |  | $ | 15 |  | $ | — |  | $ | — |
Investments |  |  |  |  |  |  |  |
Treasury bills | $ | 2,309 |  | $ | — |  | $ | 2,309 |  | $ | — |
Government bonds |  | 1,003 |  |  | 1,003 |  |  | — |  |  | — |
Total Investments | $ | 3,312 |  | $ | 1,003 |  | $ | 2,309 |  | $ | — |
| Fair Value Measurements Using |
December 31, 2024 | Fair Value |  | Level 1 |  | Level 2 |  | Level 3 |
Cash equivalents |  |  |  |  |  |  |  |
Money market | $ | 74 |  | $ | 74 |  | $ | — |  | $ | — |
Investments |  |  |  |  |  |  |  |
Treasury bills |  | 2,062 |  |  | — |  |  | 2,062 |  |  | — |
Government agency bonds |  | 772 |  |  | 772 |  |  | — |  |  | — |
Money market |  | 696 |  |  | 696 |  |  | — |  |  | — |
Total Investments | $ | 3,530 |  | $ | 1,468 |  | $ | 2,062 |  | $ | — |

Liabilities recorded at fair value

Convertible Notes

As detailed in Note 13 below, the Company elected to account for convertible notes (consisting of funding notes and exchange notes) issued on February 13, 2025 at fair value as of the issuance date and immediately before their settlement date of March 4, 2025. The convertible notes are valued using the binomial lattice model with the following key level 3 inputs:

|  | At issuance |  |  | At settlement |
Interest rate |  | 4.18% - 4.28% |  |  |  | 3.99 | %
Remaining term (years) |  |  | 1.0 |  |  |  | 0.94 |
Volatility |  |  | 77.5 | % |  |  | 119.2 | %
Fair value of common stock |  | $ | 1.20 |  |  | $ | 0.30 |

The following table provides a roll forward of the fair value of the convertible notes during the nine months ended September 30, 2025 (in thousands):

|  | Funding Notes |  |  | Exchange Notes |
Beginning balance as of January 1, 2025 |  | $ | — |  |  | $ | — |
Issuance |  |  | 3,968 |  |  |  | 3,763 |
Change in fair value |  |  | (265 | ) |  |  | (251 | )
Settlement |  |  | (3,703 | ) |  |  | (3,512 | )
Ending balance as of September 30, 2025 |  | $ | — |  |  | $ | — |

Warrants

As detailed in Note 13 below, the Company issued March 2025 Series A and March 2025 Series B common stock warrants in connection with the March 2025 Private Placement. The March 2025 Series A and March 2025 Series B common stock warrants are accounted for as liabilities at fair value at issuance date, and immediately prior to their extinguishment and modification, respectively, on June 17, 2025. The March 2025 Series A and March 2025 Series B common stock warrants were valued using the Monte Carlo simulation, with the following key level 3 inputs:

|  | At issuance |  |  | At modification and extinguishment |
Interest rate |  |  | 3.98 | % |  |  | 3.91 | %
Remaining term (years) |  |  | 6.1 |  |  |  | 4.9 |
Volatility |  |  | 123.7 | % |  |  | 135.6 | %

The March 2025 Series B Warrants were valued immediately prior to exercise, using the Monte Carlo simulation with the following inputs for the exercises that occurred before the modification on June 17, 2025:

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|  | At exercise
Interest rate |  | 3.85% - 4.06%
Remaining term (years) |  | 4.9 - 5.0
Volatility |  | 133.9% - 135.8%

In addition, the February 2025 Warrants issued in connection with the Funding Notes were required to be classified as liabilities and recorded at fair value. The Company estimated the fair value of the February 2025 Warrants using the Black Scholes model at issuance as of February 13, 2025 and as of their redemption date of March 4, 2025, using the following level 3 inputs:

|  | At issuance |  |  | At settlement |
Interest rate |  |  | 4.30 | % |  |  | 4.30 | %
Remaining term (years) |  |  | 5.0 |  |  |  | 4.95 |
Volatility |  |  | 98.5 | % |  |  | 102.1 | %
Fair value of common stock |  | $ | 1.20 |  |  | $ | 0.30 |

The following table provides a roll forward of the fair value of liability classified common stock warrants during the nine months ended September 30, 2025 (in thousands):

| February 2025 Warrants |  |  | March 2025 Series A Warrants |  |  | March 2025 Series B Warrants |  |  | Total |
Beginning balance as of January 1, 2025 | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |
Issuance |  | 2,762 |  |  |  | 2,005 |  |  |  | 11,243 |  |  |  | 16,010 |
Change in fair value |  | (2,231 | ) |  |  | 335 |  |  |  | 5,043 |  |  |  | 3,147 |
Settlement |  | (531 | ) |  |  | — |  |  |  | (858 | ) |  |  | (1,389 | )
Modification and extinguishment |  | — |  |  |  | (2,340 | ) |  |  | (4,461 | ) |  |  | (6,801 | )
Reclassified to equity |  | — |  |  |  | — |  |  |  | (10,967 | ) |  |  | (10,967 | )
Ending balance as of September 30, 2025 | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |

5. Short-Term Investments

The Company classified short-term investments as available-for-sale securities, as the sale of such investments may be required prior to maturity to facilitate the execution of management strategies. During the three and nine months ended September 30, 2025, the unrealized gain on the Company's available-for-sale securities was immaterial, and not presented separately in the condensed consolidated statements of operations.

The Company classified all investments with maturities longer than three months from the date of purchase as short-term investments in the condensed consolidated balance sheets, reflecting its intent and ability to use these assets to meet the liquidity requirements of current operations. The following table summarizes contractual maturities of available-for-sale securities as of September 30, 2025 (in thousands):

| Amortized Cost |  | Estimated Fair Value |
Due in one year or less | $ | 2,309 |  | $ | 2,309 |
Due after one year through five years |  | — |  |  | — |
Due after five years |  | 1,003 |  |  | 1,003 |
Total Investments | $ | 3,312 |  | $ | 3,312 |

6. Loss per Share

Basic per share data is computed by dividing net income or loss applicable to common stockholders by the weighted average number of common shares outstanding during the period. Diluted per share data is computed by dividing net income or loss applicable to common stockholders by the weighted average number of common shares outstanding during the period increased to include, if dilutive, the number of additional common shares that would have been outstanding as calculated using the treasury stock or if-converted method, as applicable. The Pre-Funded Warrants were included in the weighted average shares outstanding calculation (as of the beginning of the period or the date of the grant, whichever was earlier) for basic and dilutive earnings per share given their nominal exercise price.

The March 2025 Series A Warrants and March 2025 Series B Warrants (and for the period in which the February 2025 Warrants, Funding Notes, and Exchange Notes, as defined in Note 13, were outstanding) were participating securities because holders of such instruments would participate in the event a dividend is paid on common stock, however such holders did not have a contractual obligation to share in the Company’s losses. As such, losses were attributed entirely to common stockholders.

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The following table sets forth the computation of basic and diluted net loss per share of common stock for the periods indicated, in thousands except share and per share data:

| Three Months Ended September 30, |  |  | Nine Months Ended September 30, |
| 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Basic and diluted net loss per common share calculation: |  |  |  |  |  |  |  |  |  |  |
Net loss | $ | (4,423 | ) |  | $ | (2,874 | ) |  | $ | (16,673 | ) |  | $ | (9,075 | )
Change in fair value of derivative instruments |  | — |  |  |  | — |  |  |  | — |  |  |  | (5,047 | )
Net loss attributable to common stockholders – basic |  | (4,423 | ) |  |  | (2,874 | ) |  |  | (16,673 | ) |  |  | (14,122 | )
Weighted average common stock outstanding – basic |  | 107,428,969 |  |  |  | 7,855,763 |  |  |  | 57,845,406 |  |  |  | 6,232,123 |
Net loss per share of common stock – basic | $ | (0.04 | ) |  | $ | (0.37 | ) |  | $ | (0.29 | ) |  | $ | (1.46 | )
Weighted average common stock outstanding - diluted |  | 107,428,969 |  |  |  | 7,855,763 |  |  |  | 57,845,406 |  |  |  | 8,452,338 |
Net loss per share of common stock - diluted | $ | (0.04 | ) |  | $ | (0.37 | ) |  | $ | (0.29 | ) |  | $ | (1.67 | )

The following table provides a summary of instruments where underlying shares issuable upon exercise or conversion were excluded from the diluted loss per share calculation for the periods presented because their effect would be anti-dilutive. Additionally, the shares underlying the February 2025 Warrants, Funding Notes and Exchange Notes, each outstanding during the nine months ended September 30, 2025, were excluded from diluted loss per share as their effect would be anti-dilutive.

| As of September 30, |
| 2025 |  |  | 2024 |
Outstanding stock options |  |  | 11,272,863 |  |  |  | 598,540 |
Outstanding restricted stock units |  |  | 2,823,857 |  |  |  | - |
Preferred stock |  |  | 28,190 |  |  |  | 28,190 |
Outstanding warrants (Note 13) |  |  | 3,141,993 |  |  |  | 706,674 |
Total |  |  | 17,266,903 |  |  |  | 1,333,404 |

7. Grant Revenue

CPRIT Grant

On September 19, 2022, the Company entered into that certain Cancer Research Grant Contract (the “CPRIT Contract”), effective as of August 31, 2022, with the Cancer Prevention and Research Institute of Texas (“CPRIT”), pursuant to which CPRIT provides the Company with a CPRIT Grant (“CPRIT Grant”) over a three-year period to fund the continued development of REYOBIQ TM for the treatment of patients with leptomeningeal metastases. The CPRIT Grant is subject to customary CPRIT funding conditions, including, but not limited to, a matching fund requirement (one dollar for every two dollars awarded by CPRIT), revenue sharing obligations upon commercialization of REYOBIQ based on specific dollar thresholds and tiered low single digit royalty rates until CPRIT receives the aggregate amount of 400% of the proceeds awarded under the CPRIT Grant, and certain reporting requirements.

The CPRIT Contract will terminate on February 28, 2026, unless terminated earlier by (a) the mutual written consent of all parties to the CPRIT Contract, (b) CPRIT for an event of default by the Company, (c) CPRIT, if the funds allocated to the CPRIT Grant become legally unavailable during the term of the CPRIT Contract and CPRIT is unable to obtain additional funds for such purposes, and (d) the Company for convenience. CPRIT may require the Company to repay some or all of the disbursed CPRIT Grant proceeds (with interest not to exceed 5% annually) in the event of the early termination of the CPRIT Contract by CPRIT for an event of default by the Company or by the Company for convenience, or if the Company relocates its principal place of business outside of the state of Texas during the CPRIT Contract term or within three years after the final payment of the grant funds.

The Company retains ownership over any intellectual property developed under the CPRIT Contract (each, a “Project Result”). With respect to non-commercial use of any Project Result, the Company granted to CPRIT a nonexclusive, irrevocable, royalty-free, perpetual, worldwide license with right to sublicense any necessary additional intellectual property rights to exploit all Project Results by CPRIT, other governmental entities and agencies of the State of Texas, and private or independent institutions of higher education located in Texas, for education, research and other non-commercial purposes.

The Company recognized $1.4 million and $3.8 million, and $1.5 million and $4.4 million in grant revenue from the CPRIT Contract during the three and nine months ended September 30, 2025 and 2024, respectively. As of September 30, 2025 and December 31, 2024, the Company had nil and $0.6 million, respectively, of grant revenue receivable related to the CPRIT Grant. As of September 30, 2025 and December 31, 2024, the Company had $1.1 million and nil of deferred grant liability related to the CPRIT Grant.

Department of Defense Award

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Effective September 1, 2024, the Company entered into an agreement with the Department of Defense office of the Congressionally Directed Medical Research Programs to receive a $3.0 million award for research and development purposes (“DoD Award”) over a three year period. The DoD Award will be used to support the planned expansion of the Company’s clinical trial for pediatric brain cancer. On October 4, 2024, the Company received its first payment under the DoD Award in the amount of $0.9 million, which was recorded as deferred grant liability as of September 30, 2025 and December 31, 2024. As of September 30, 2025 and December 31, 2024, no amount of grant revenue was recognized related to the DoD Award.

8. Commitments and Contingencies

Leases

The Company leases certain office space in Charlottesville, Virginia (the “Charlottesville Lease”). The Charlottesville Lease expires on March 31, 2026.

Manufacturing Agreement with SpectronRx

On November 5, 2024, the Company entered into a manufacturing services agreement with SpectronRx for drug product development and manufacturing, which includes an initial commitment fee of $0.3 million. Under this agreement, the Company owns all rights to intellectual property related to the products developed, while SpectronRx retains rights to its own technology. SpectronRx is required to negotiate a commercial supply agreement upon six months' written notice before the Company's first commercial manufacturing needs. The agreement will remain in place for five years, automatically renewing for successive one-year terms unless terminated with six months' notice. During the nine months ended September 30, 2025 and year ended December 31, 2024, the Company did not recognize any expenses related to this agreement.

Other commitments and contingencies

The Company has entered into agreements with various research organizations for preclinical and clinical development studies, which have provisions for cancellation. Under the terms of these agreements, the vendors provide a variety of services including conducting research, recruiting and enrolling patients, monitoring studies and data analysis. Payments under these agreements typically include fees for services and reimbursement of expenses. The timing of payments due under these agreements is estimated based on study progress. As of September 30, 2025, the Company did no t have any clinical research study obligations.

The Company has entered into service and subscription-based agreements, which are recorded in accounts payable and accrued expenses, with an offsetting amount included in deferred costs within other current assets.

Legal proceedings

From time to time, the Company is subject to legal proceedings and claims, whether asserted or unasserted, that arise in the ordinary course of business. Due to their nature, such legal proceedings involve inherent uncertainties including, but not limited to, court rulings, negotiations between affected parties and governmental actions. Management assesses the probability of loss for such contingencies and accrues a liability and/or discloses the relevant circumstances, as appropriate.

9. Composition of Certain Financial Statement Captions

As of September 30, 2025 and December 31, 2024, other current assets were comprised of the following (in thousands):

|  | September 30, 2025 |  |  | December 31, 2024 |
Prepaid services |  | $ | 551 |  |  | $ | 87 |
Deferred costs (Note 8) |  |  | 299 |  |  |  | 436 |
Prepaid insurance |  |  | 135 |  |  |  | 559 |
Total other current assets |  | $ | 985 |  |  | $ | 1,082 |

10. Line of Credit Facility

On May 31, 2024, the Company drew down $3.3 million on a margin loan facility under a line of credit (the “Pershing Credit Facility”) with Pershing LLC (“Pershing”), an affiliate of The Bank of New York Mellon Corporation. The available credit line limit under the Pershing Credit Facility fluctuated based on the Company’s request for extensions from time to time, subject to the value of the collateralized marketable securities the Company holds with Pershing, provided that the amount available to draw under the Pershing Credit Facility cannot exceed 91.5% of the value of the collateralized marketable securities deposited with Pershing. Depending on the value of the marketable securities the Company held with Pershing, Pershing could have required the Company from time-to-time to deposit additional funds or marketable securities in order to restore the level of collateral to an acceptable level. The amounts borrowed under the Pershing Credit Facility were due on demand. As of September 30, 2025 and December 31, 2024, the Company held collateralized marketable securities with Pershing with a total value of zero and $3.5 million, respectively.

Borrowings under the Pershing Credit Facility bore interest at the target interest rate set by the Federal Open Market Committee,

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subject to a floor of 5.5%, plus a spread of 1.75% and applicable fees of 0.5%, subject to a maximum interest rate of the then applicable Prime Rate as published in The Wall Street Journal, plus 3.0%. Interest payments thereunder were calculated on a monthly basis and, unless paid, were added to the outstanding balance under the Pershing Credit Facility. The proceeds under the Pershing Credit Facility are available for working capital needs and other general corporate purposes. Volatility in the global markets could cause the interest rate to fluctuate from time to time increasing the Company’s costs, or could cause Pershing to terminate the Company’s ability to borrow funds. In addition, borrowings under the Pershing Credit Facility have the effect of limiting the Company’s use of cash and marketable securities.

On January 3, 2025, the Pershing Credit Facility was fully repaid and the collateralized marketable securities were fully redeemed.

11. License Agreements

UT Health Science Center at San Antonio (“UTHSCSA”) License Agreement

On December 31, 2021, the Company entered into a Patent and Know-How License Agreement (the “UTHSCSA License Agreement”) with The University of Texas Health Science Center at San Antonio (“UTHSCSA”), pursuant to which UTHSCSA granted the Company an irrevocable, perpetual, exclusive, fully paid-up license, with the right to sublicense and to make, develop, commercialize and otherwise exploit certain patents, know-how and technology related to the development of biodegradable alginate microspheres (“BAM”) containing nanoliposomes loaded with imaging and/or therapeutic payloads.

NanoTx License Agreement

On March 29, 2020, the Company and NanoTx, Corp. (“NanoTx”) entered into a Patent and Know-How License Agreement, pursuant to which NanoTx granted the Company an irrevocable, perpetual, exclusive, fully paid-up license, with the right to sublicense and to make, develop, commercialize and otherwise exploit certain patents, know-how and technology related to the development of radiolabeled nanoliposomes.

The transaction terms included an upfront payment of $0.4 million in cash and $0.3 million in the Company's voting stock. The transaction terms also included success-based milestone and royalty payments contingent on key clinical, regulatory and sales milestones, as well as the requirement to pay 15% of any non-dilutive monetary awards or grants received from external agencies to support product development of the nanoliposome encapsulated BMEDA-chelated radioisotope, which includes grants from CPRIT. As of September 30, 2025, the Company accrued $0.3 million of payments due to NanoTx as a result of the CPRIT Grant proceeds received (see Note 7, Grant Revenue of the condensed consolidated financial statements for additional information).

12. Biocept Asset Acquisition

On April 26, 2024, the Company, after having its bid accepted by the United States Bankruptcy Court for the District of Delaware, acquired from Biocept, Inc. (“Biocept”), for a total cash payment of $400,000, substantially all of the right, title and interest in a cerebrospinal fluid cancer diagnostic portfolio (the “CNSide® Platform”), including (i) intellectual property, (ii) inventory and raw materials, and (iii) data, information, results and reports pertaining to the completed and on-going clinical studies involving the use of the CNSide Platform (including, but not limited to, the FORESEE clinical study that was being conducted by Biocept), related to the development, making, selling, and exporting or importing of the CNSide proprietary cell enumeration test (the “CNSide Test”).

The Company concluded that the acquisition of the Biocept assets was not a business combination, as Biocept did not meet the definition of a business in ASC 805, Business Combination. The Company accounted for the asset purchase transaction under the authoritative guidance for asset acquisitions, and allocated the costs of acquisition of approximately $45,000 among the assets acquired based on the relative fair value of such assets, which is predominately concentrated in the intellectual property acquired including patents and trademarks. The intangible assets acquired from Biocept are capitalized and amortized over a useful life of four years.

13. Stockholders’ Equity

Preferred Stock

The Company has authorized 5,000,000 shares of preferred stock, par value $0.001 per share. The Company’s board of directors is authorized to designate the terms and conditions of any preferred stock the Company issues without further action by the common stockholders.

Series B and C Preferred Stock

As of September 30, 2025, there were 938 outstanding shares of Series C Preferred Stock that can be converted into an aggregate of 27,792 shares of common stock, and 1,014 shares of Series B Convertible Preferred Stock that can be converted into an aggregate of 398 shares of common stock.

Common Stock

February 2025 SPEA Agreements

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On February 13, 2025 (the “February 2025 Closing Date”), the Company entered into a Securities Purchase and Exchange Agreement (the “February 2025 SPEA”) with certain existing accredited investors (the “February 2025 Purchasers”). Pursuant to the February 2025 SPEA, on the February 2025 Closing Date the Company issued secured convertible promissory notes (the “Funding Notes”) in the aggregate principal amount of $3.3 million together with common stock purchase warrants (the “February 2025 Warrants”) to purchase 3,002,009 shares of the Company common stock, par value $0.001 and exercise price of $1.12 per share (the “February 2025 Warrant Exercise Price”). The aggregate purchase price for the Funding Notes and the February 2025 Warrants was approximately $3.7 million (the “Aggregate Purchase Price”) and included proceeds from the February 2025 Purchasers of $0.125 per February 2025 Warrant in accordance with Nasdaq listing rules. The Funding Notes would mature on February 13, 2026, and bore interest at a rate of 10% per annum, subject to increase upon events of default. The February 2025 Warrants were exercisable for five-years from the date of issuance.

The Funding Notes, accrued interest and February 2025 warrants were repurchased by the Company subsequent to consummation of the March 2025 Private Placement for proceeds of $4.2 million.

Security Interest

The obligations of the Company under the February 2025 SPEA, Funding Notes and Exchange Notes (as defined below) were secured by a pledge of substantially all of the assets of the Company pursuant to a security agreement, dated as of the February 2025 Closing Date, among the Company, CNSide Diagnostics, LLC (a subsidiary of the Company, “CNSide Diagnostics”), and Iroquois Master Fund Ltd., as collateral agent for the February 2025 Purchasers (the “Security Agreement”), subject to certain exceptions. The Security Agreement contained certain customary affirmative and negative covenants, including limitations on the Company’s and CNSide Diagnostic’s ability to dispose of assets, subject to customary exceptions. The repayment of the Company’s obligations under the February 2025 SPEA and Notes were guaranteed pursuant to a subsidiary guarantee, dated as of the February 2025 Closing Date (the “Subsidiary Guarantee”), by and among CNSide Diagnostics and the February 2025 Purchasers. The Security Agreement and the Subsidiary Guarantee were subsequently terminated after the closing of the private placement pursuant to the March 2025 SPA (as defined below).

Exchange Notes

As disclosed below, the Company entered into the May 2024 Purchase Agreement (defined below), with the May 2024 Purchasers for the private placement of securities, including the May 2024 Series A Warrants to purchase an aggregate of up to 3,591,532 shares of common stock. The May 2024 Purchase Agreement included certain limitations and restrictions on the Company’s ability to issue securities and provided the May 2024 Purchasers and the other investors signatories to the May 2024 Purchase Agreement participation rights in future equity and equity-linked offerings of securities, subject to certain limited exceptions (the “Financing Restrictions”). On the February 2025 Closing Date, pursuant to the February 2025 SPEA, the Company issued to the May 2024 Purchasers secured convertible promissory notes in the aggregate amount of $3.2 million (the “Exchange Notes”) in exchange for cancellation of the May 2024 Series A Warrants held by the May 2024 Purchasers, and the May 2024 Purchasers entered into a second amendment to the May 2024 Purchase Agreement to eliminate the Financing Restrictions. The terms and conditions of the Exchange Notes were substantially identical in all material respects to the Funding Notes. The Security Agreement and Subsidiary Guarantee also applied to the obligations under the Exchange Notes. The Exchange Notes were exchanged after the closing of the March 2025 Private Placement as defined below.

Both the Funding Notes and the Exchange Notes contained embedded conversion features that were required to be bifurcated and accounted for as derivative liabilities. The Company evaluated authoritative guidance for accounting for convertible debt instruments and elected to account for the Funding Notes and Exchange Notes at fair value. Consequently, the Company recorded the Funding Notes and Exchange Notes in their entirety at fair value at issuance and immediately before settlement, with changes in fair value recorded as change in fair value of derivative instruments in the condensed consolidated statements of operations between the issuance date and the settlement date.

The Company entered into the transaction due to immediate funding requirements. Under authoritative guidance, if the fair value of a warrant liability exceeds the proceeds received in an arm’s length transaction with no rights or privileges that require separate accounting recognition as an asset identified, then the warrant liability is recorded at fair value with the excess of fair value over proceeds recognized as a loss in earnings. The Exchange Notes, Funding Notes and associated warrants were recorded at fair value on the issuance date at $3.8 million, $4.0 million and $2.7 million, respectively. The excess of the fair value of the instruments issued over cash received of $3.7 million and the carrying value of the May 2024 Series A Warrants exchanged of $3.7 million, in the amount of $3.1 million was recorded as a financing expense in the statement of operations for the nine months ended September 30, 2025.

Changes in the fair value of Exchange Notes, Funding Notes and February 2025 Warrants between issuance date and settlement date, in the amount of a gain of $0.3 million, a gain of $0.3 million and a gain of $2.2 million, respectively, were recorded as change in the fair value of derivative instruments in the statement of operations for the nine months ended September 30, 2025.

March 2025 Private Placement

On March 4, 2025, the Company entered into a securities purchase agreement (the “March 2025 SPA”) with accredited investors, including certain existing stockholders of the Company (collectively, the “March 2025 Private Placement Purchasers”) for a private placement of securities (the “March 2025 Private Placement”). The March 2025 SPA, provided for the sale and issuance

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by the Company of an aggregate of 28,042,140 shares (the “March 2025 Private Placement Shares”) of the Company’s common stock, or, at the election of each March 2025 Private Placement Purchaser, pre-funded warrants to purchase Common Stock (the “March 2025 Pre-Funded Warrants”), exercisable immediately at an exercise price of $0.001 per share (the “March 2025 Pre-Funded Warrant Shares”), with each March 2025 Private Placement Share or March 2025 Pre-Funded Warrant accompanied by (i) a Series A common warrant (the “March 2025 Series A Warrants”) to purchase one share of common stock (the “March 2025 Series A Warrant Shares”), and (ii) one Series B common warrant (the “March 2025 Series B Warrants”) to purchase one share of common stock (see below for additional details on the Series B Warrants cashless exercise provisions) (the “March 2025 Series B Warrant Shares,” and together with the March 2025 Series A Warrant Shares, the “March 2025 Common Warrant Shares”). The March 2025 Private Placement Shares, March 2025 Pre-Funded Warrants, March 2025 Pre-Funded Warrant Shares, March 2025 Series A Warrants, March 2025 Series B Warrants, and the March 2025 Common Warrant Shares are collectively referred to herein as the “March 2025 Securities.” Pursuant to the March 2025 SPA, the Company issued to the March 2025 Private Placement Purchasers 4,069,738 March 2025 Private Placement Shares, 23,972,400 March 2025 Pre-Funded Warrants, 28,042,138 March 2025 Series A Warrants and 28,042,138 March 2025 Series B Warrants. As of September 30, 2025, all March 2025 Series A Warrants and March 2025 Series B Warrants were settled as a result of cancellation, exchanges or exercises as detailed below, and 2,611,809 March 2025 Pre-Funded Warrants remained outstanding.

The combined purchase price of $0.66 for each March 2025 Private Placement Share or $0.659 for each March 2025 Pre-Funded Warrant in the March 2025 Private Placement, together with one accompanying March 2025 Series A Warrant and one accompanying March 2025 Series B Warrant, represents the applicable “Minimum Price” in accordance with Nasdaq Rule 5635(d).

The initial exercise price of each March 2025 Series A Warrant issued in the March 2025 Private Placement was $1.32 per share of common stock. The March 2025 Series A Warrants were exercisable only following stockholder approval and expire five (5) years thereafter. The March 2025 Series A Warrants were subject to certain price reset, share combination event and anti-dilution provisions which, if triggered, provided that the number of shares issuable upon exercise of the March 2025 Series A Warrants would downward adjust, subject to a floor price of $0.132 (the “Floor Price”), and the number of shares issuable upon exercise therefor would increase such that the aggregate exercise price remained unchanged. The March 2025 Series A Warrants were extinguished as part of the Letter Agreement on June 17, 2025 as discussed below.

The initial exercise price of each March 2025 Series B Warrant issued in the March 2025 Private Placement was $1.98 per share of common stock. The March 2025 Series B Warrants were exercisable only following stockholder approval and expire two and one-half (2.5) years thereafter. The March 2025 Series B Warrants were subject to certain price reset and share combination event provisions which, if triggered, provided that the number of shares issuable upon exercise of the March 2025 Series B Warrants would downward adjust, subject to the Floor Price, and the number of shares issuable upon exercise therefor would increase such that the aggregate exercise price remained unchanged. In addition, the March 2025 Series B Warrant alternative cashless exercise provision provided that the March 2025 Series B Warrant could be exercised without further payment to the Company and for three times the number of shares of common stock then subject to the March 2025 Series B Warrant.

The March 2025 Pre-Funded Warrants will be exercisable from the date of issuance until exercised in full. The March 2025 Pre-Funded Warrants, March 2025 Series A Warrants and March 2025 Series B Warrants may not be exercised to the extent that immediately following such exercise, the holder would beneficially own greater than 4.99% (or, at the election of the holder, greater than 9.99%) of the Company’s outstanding common stock.

In connection with the March 2025 Private Placement, the Company issued 3,077,270 shares of common stock, 19,650,000 shares of March 2025 Pre-Funded Warrants in lieu thereof, and accompanying 22,727,270 March 2025 Series A Warrants and 22,727,270 March 2025 Series B Warrants in consideration of new capital subscriptions. In addition, the Company issued 992,468 shares of common stock, 4,322,400 March 2025 Pre-Funded Warrants in lieu thereof, and accompanying 5,314,870 March 2025 Series A Warrants and 5,314,870 March 2025 Series B Warrants, were issued in exchange for the cancelation of approximately $3.2 million in aggregate principal amount of the Exchange Notes.

The Company evaluated the terms of the February 2025 Warrants, March 2025 Series A Warrants and March 2025 Series B Warrants under authoritative guidance and concluded that each of the instruments should be accounted for as a liability instrument at fair value at issuance and each subsequent balance sheet date until settlement, with changes in the fair value recorded in the condensed consolidated statement of operations. The March 2025 Pre-Funded Warrants meet the criteria to be recorded as equity in the Company's condensed consolidated balance sheet.

The March 2025 Private Placement closed on March 7, 2025 (the “March 2025 Closing Date”). The aggregate gross proceeds at the March 2025 Closing Date totaled approximately $15.0 million. The gross proceeds, along with the fair value of the February 2025 Warrants of $0.5 million and Exchange Notes of $3.5 million as of the settlement date of March 4, 2025, were first allocated to the warrant liability instruments at their full fair value, totaling $13.2 million, with the remainder of $5.8 million recorded to common stock and additional paid-in capital in equity of the condensed consolidated balance sheet. Total offering expenses of $1.4 million were allocated based on the allocated amount of proceeds to warrant liabilities and equity, with $1.0 million recorded as warrant issuance expenses and expensed as incurred, and the remaining $0.4 million recorded as common stock issuance costs in additional paid-in capital.

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On May 2, 2025, the Company’s stockholders approved, among other things, the March 2025 Series A Warrants and March 2025 Series B Warrants, and an amendment to the Company’s Certificate of Incorporation, as amended, to increase the authorized share capital of the Company to an amount sufficient to cover the shares of common stock issuable upon the exercise of the March 2025 Series A Warrants and March 2025 Series B Warrants. As part of the March 2025 Series A Warrants and March 2025 Series B Warrants agreement, the exercise price of the March 2025 Series A Warrants and March 2025 Series B Warrants were both reset on May 19, 2025 to $0.4373 per share. Prior to modification of the March 2025 Series B Warrants as part of the Letter Agreement (as further described below), certain March 2025 Series B Warrants were cashless exercised for the issuance of 21,482,492 shares of common stock The liability classified March 2025 Series B Warrants were remeasured immediately prior to exercise, which resulted in a $3.8 million gain on change in fair value for the nine months ended September 30, 2025, and a $0.8 million credit to additional paid-in capital.

Letter Agreement

On June 17, 2025, the Company and the March 2025 Private Placement Purchasers entered into a letter agreement (the “Letter Agreement”) with each of the March 2025 Private Placement Purchasers in an effort to, among other items, minimize the dilutive impact of the March 2025 Private Placement. The Letter Agreement extinguished the March 2025 Series A Warrants, modified the March 2025 Series B Warrants, and provided for the return and cancellation of Private Placement Shares and Pre-Funded Warrants, as further discussed in the following paragraphs.

As part of the Letter Agreement, all March 2025 Series A Warrants were cancelled. As of March 31, 2025, the fair value of the March 2025 Series A Warrant liability was $5.0 million. On June 17, 2025, t he March 2025 Series A Warrants were immediately remeasured to fair value prior to their cancellation, which resulted in a $2.7 million gain on change in fair value attributable to the March 2025 Series A Warrants for the nine months ended September 30, 2025. The extinguishment of the March 2025 Series A Warrants was recognized as a $2.3 million capital contribution and recorded to additional paid-in capital, as the extinguishment was deemed equivalent to a capital contribution by existing shareholders of the Company.

As part of the same transaction, the March 2025 Series B Warrants were amended (the "Amended March 2025 Series B Warrants"), to (a) reduce the overall number of March 2025 Series B Warrant Shares issuable upon exercise of the Series B Warrants to an aggregate of up to 35,536,380 Series B Warrant Shares, (b) reduce the alternative cashless exercise ratio in such March 2025 Series B Warrants from 3:1 to 1:1, (c) remove provisions contained in the March 2025 Series B Warrants that would otherwise reduce the Company’s stockholders’ equity, and (d) reset the exercise price of the Amended March 2025 Series B Warrants back to $1.98 per share. As a result of the Letter Agreement, the Amended March 2025 Series B Warrants no longer fail the indexation guidance under ASC 815, Derivatives and Hedging, resulting in a reclassification from liability to equity. Immediately prior to reclassification, the March 2025 Series B Warrant liability was remeasured, and $4.5 million was recognized as a capital contribution and recorded to additional paid-in capital, as the modification of the March 2025 Series B Warrants was deemed equivalent to a capital contribution by existing shareholders of the Company. T he remeasured fair value of the March 2025 Series B warrant liability, in the amount of $11.0 million was reclassified to equity. After the June 17, 2025 modification, 34,794,540 of the Amended March 2025 Series B Warrants were cashless exercised resulting in the issuance of 34,794,540 shares of common stock.

Lastly, in conjunction with the Letter Agreement, each of the March 2025 Private Placement Purchasers agreed to return an aggregate of 12,241,986 Private Placement Shares and Pre-Funded Warrants issuable for an aggregate of 10,633,650 Pre-Funded Warrant Shares, held by them as of the date of the Letter Agreement, upon request of the Company (the "Letter Agreement Repurchase Option"), which were issued pursuant to the March 2025 Private Placement Purchase Agreement for a value of $0.66 per Private Placement Share and $0.659 per Pre-Funded Warrant. In exchange therefor, the Company agreed to repay the March 2025 Private Placement Purchasers holding such securities 115% of such value, using 90% of the proceeds from any capital raised by the Company subsequent to July 1, 2025. The Company and each of the March 2025 Private Placement Purchasers also agreed to waive any restrictions on subsequent equity sales and variable rate transactions contained in March 2025 Private Placement Purchase Agreement to allow for such repayment. During the three and nine months ended September 30, 2025, the Company paid the March 2025 Private Placement Purchasers $2.3 million and 3,472,740 shares were returned and cancelled under the terms of the Letter Agreement.

Support Letters

On July 11, 2025, the Company and certain March 2025 Private Placement Purchasers party to the Letter Agreement entered into that certain letter of support (the “Support Letters”) to modify certain portions of the Letter Agreement as between the Company and each of such March 2025 Private Placement Purchasers. In the event that the Company reasonably believes that, within the 30 days (the “Modification Period”) prior to the end of any fiscal quarter, the Company will have stockholders’ equity in an amount below $3.0 million as of the end of such fiscal quarter (the “Potential Equity Deficiency”), the Subsequent Financing Percentage (as defined in the Letter Agreement) shall be modified from 90% to 50% for any Subsequent Financing (as defined in the Letter Agreement) that occurs during the Modification Period pursuant to the Lincoln Park Purchase Agreement. Upon the end of the Modification Period, the Subsequent Financing Percentage shall be reverted to 90%, and such percentage shall apply to all Subsequent Financings, including all Subsequent Financings pursuant to the Lincoln Park Purchase Agreement. In the event the Company desires to trigger the modification of the Subsequent Financing Percentage, the Company agrees to supply the purchaser who executed a Support Letter with a pro forma balance sheet to evidence its reasonable belief of the Potential Equity Deficiency approximately 30 days prior to each end of fiscal quarter once the books for prior months are closed. In accordance

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with the Support Letters, the Company made a cash payment of $0.5 million to such purchasers for a total cash payment of $2.3 million, which was recorded as a reduction to additional paid-in capital in the condensed consolidated balance sheet as of September 30, 2025. Such payment counted as cash received by the purchaser towards its Maximum Amount. Each Support Letter also granted the purchaser party to the letter a participation right in certain future financings of the Company for a period of 12 months.

First Amendment to the February 2025 SPEA

In connection with entering into the March 2025 SPA, the Company entered into that certain First Amendment to the February 2025 SPEA (the “First Amendment”). The February 2025 SPEA included certain limitations and restrictions on the Company’s ability to issue securities and provided the investors with participation rights in future equity and equity-linked offerings of securities, subject to certain limited exceptions (the “New Financing Restrictions”). Pursuant to the First Amendment, subject to consummation of the March 2025 Private Placement, the Company agreed to repurchase from the Investors $3.4 million in principal amount of the Company’s Funding Notes and accrued interest, along with the February 2025 Warrants issued pursuant to the February 2025 SPEA for an aggregate purchase price of $4.2 million. In exchange for the repurchase by the Company of the Funding Notes and SPEA Warrants, the February 2025 Purchasers agreed to consent to the March 2025 Private Placement and eliminate the New Financing Restrictions.

May 2024 Private Placement

On May 5, 2024, the Company entered into a securities purchase agreement (the “May 2024 Securities Purchase Agreement”) with certain investors, including certain of the Company’s directors and executive officers (“Company Insiders”) (collectively, the “May 2024 Purchasers”), for the sale and issuance by the Company of its securities (the “Initial Subscription”). On May 8, 2024, the Company entered into a first amendment to the May 2024 Securities Purchase Agreement (together with the May 2024 Securities Purchase Agreement, the “May 2024 Purchase Agreement”), for the sale and issuance by the Company of additional securities to two of the May 2024 Purchasers (the “Additional Subscription,” and together with the Initial Subscription, the “May 2024 Private Placement”). The May 2024 Purchase Agreement provides for the sale and issuance by the Company of an aggregate of 3,591,532 shares (the “May 2024 Private Placement Shares”) of the Company’s common stock or, at the election of each May 2024 Purchaser, Pre-Funded warrants (the “May 2024 Pre-Funded Warrants”), exercisable immediately at an exercise price of $0.001 per share, with each May 2024 Private Placement Share or May 2024 Pre-Funded Warrant accompanied by (i) a May 2024 Series A common warrant (“May 2024 Series A Warrants”) to purchase one share of common stock, for an aggregate of 3,591,532 May 2024 Series A Warrants, and (ii) one May 2024 Series B common warrant (“May 2024 Series B Warrants”) to purchase one share of common stock, for an aggregate of 3,591,532 May 2024 Series B Warrants.

The combined purchase price for each May 2024 Private Placement Share and May 2024 Pre-Funded Warrant from the Initial Subscription was $2.022, and $2.158 from the Additional Subscription, in each case together with one accompanying May 2024 Series A Warrant and one accompanying May 2024 Series B Warrant provided, that the Company Insiders participated in the Initial Subscription at an offering price of $2.04 per May 2024 Private Placement Share and accompanying May 2024 Series A Warrant and May 2024 Series B Warrant.

The exercise price of May 2024 Series A Warrants and May 2024 Series B Warrants from the Initial Subscription is $1.772 per share from the Initial Subscription and $1.908 per share from the Additional Subscription, provided that the exercise price for the May 2024 Series A Warrants and May 2024 Series B Warrants issued to the Company Insiders is $1.79 per share. Subject to certain ownership limitations, the May 2024 Series A Warrants will be exercisable until May 9, 2029, which is the five-year anniversary of issuance. Subject to certain ownership limitations, the May 2024 Series B Warrants will be exercisable until May 9, 2029. The May 2024 Pre-Funded Warrant will not expire until exercised in full.

Prior to the Amendment and Restatements (as defined below), if a holder of a May 2024 Series A Warrant or a May 2024 Series B Warrant was unable to exercise the warrant due to the limitation contained in the warrant that restricts the holder from owning above a specified beneficial ownership level (generally 4.99% or 9.99%) as the result of exercise of the warrant, then the holder had the right to elect upon exercise of the warrant to receive a May 2024 Pre-Funded Warrant for the same number of shares of common stock that would otherwise have been received upon exercise of the warrant. In addition, prior to the Amendment and Restatements, the May 2024 Series A Warrants and May 2024 Series B Warrants provided for a call right starting June 24, 2025, in favor of the Company, if the volume-weighted average price of the shares of common stock exceeds specified prices.

The May 2024 Private Offering closed on May 9, 2024. The Company issued 1,439,988 shares of common stock, 2,151,544 May 2024 Pre-Funded Warrants, 3,591,532 May 2024 Series A Warrants and 3,591,532 May 2024 Series B Warrants to purchase shares of its common stock in connection with the May 2024 Private Placement. The net proceeds from the May 2024 Private Placement were approximately $7.3 million.

The Company reviewed the terms of the May 2024 Pre-Funded Warrants, May 2024 Series A Warrants and May 2024 Series B Warrants under the authoritative accounting guidance as of the issuance date.

As described above, the May 2024 Series A Warrants and May 2024 Series B Warrants were initially classified as liabilities for the reason that they could have been exercised into either shares of common stock or May 2024 Pre-Funded Warrants at the holder’s option and thus failed the indexation guidance under ASC 815, Derivatives and Hedging. The May 2024 Series A Warrant and May 2024 Series B Warrant liability were initially recorded at fair value as of the issuance date, and under the terms of the

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May 2024 Series A Warrants and May 2024 Series B Warrants when issued that liability was subject to adjustment to estimated fair value at each balance sheet date until the warrants were settled. R efer below for additional information regarding the amendment of the May 2024 Series A Warrants and May 2024 Series B Warrants that eliminated the ability of the May 2024 Series A Warrants and May 2024 Series B Warrants to be exercised into Pre-Funded Warrants, and as a result, the reclassification of the May 2024 Series A and B Warrants from liability to equity section of the consolidated balance sheet.

The May 2024 Pre-Funded Warrants are equity classified because they (1) are freestanding financial instruments that are legally detachable and separately exercisable from the common stock, (2) are immediately exercisable, (3) do not embody an obligation for the Company to repurchase its shares, (4) permit the holder to receive a fixed number of shares of common stock upon exercise, (5) are indexed to the Company’s common stock and (6) meet the equity classification criteria.

T he proceeds from the May 2024 Private Placement were first allocated to the full fair value of the May 2024 Series A Warrants and May 2024 Series B Warrants due to the initial liability classification. As disclosed in Note 4, Fair Value Measurements, the fair value of the May 2024 Series A Warrants and May 2024 Series B Warra nts at issuance was $10.9 million. Under authoritative guidance, if the fair value of a warrant liability exceeds the proceeds received in an arm’s length transaction with no rights or privileges that require separate accounting recognition as an asset identified, then the warrant liability is recorded at fair value with the excess of fair value over proceeds recognized as a loss in earnings. The Company recognized approximately $3.5 million in financing expense in the consolidated statement of operations during year ended December 31, 2024, which represents the excess of the fair value of the May 2024 Series A Warrants and May 2024 Series B Warrants at issuance over the proceeds. During the year ended December 31, 2024, the Company recognized a fair value gain on warrant liability of $5.7 million. Proceeds from the May 2024 Private Placement are shown as cash from financing transactions and the gain on warrant liability is included as an adjustment to reconcile the net loss to net cash used in operating activities in the consolidated statements of cash flows for the year ended December 31, 2024.

In addition, total offering expenses related to the May 2024 Private Placement of $0.4 million were recorded as a component of other expenses as the entire proceeds were allocated to the warrant liability, which, prior to the amendment described below, could be settled with either the Company’s shares of common stock or May 2024 Pre-Funded Warrants, which are exercisable into the Company’s shares of common stock at any time at the holders’ option, but not in cash payment to the holders.

Amendment and Restatement of May 2024 Series A Warrants and May 2024 Series B Warrants

On August 9, 2024, the Company amended and restated the May 2024 Series A Warrants and May 2024 Series B Warrants (the “Amendment and Restatements”) issued in the May 2024 Private Placement. The Amendment and Restatements eliminated the ability of the holders of the May 2024 Series A Warrants and May 2024 Series B Warrants to elect to purchase Pre-Funded Warrants upon exercise of the May 2024 Series A Warrants and May 2024 Series B Warrants in lieu of shares of common stock if the holder would have been restricted because of the specified beneficial ownership level in the May 2024 Series A Warrants and May 2024 Series B Warrants.

In addition, the Amendment and Restatements eliminated the Company’s call right under the terms of the May 2024 Series A Warrants to call the May 2024 Series A Warrants after June 24, 2025, if the volume-weighted average price of shares of common stock exceeded specified prices. There were no other changes in the terms of the May 2024 Series A Warrants and May 2024 Series B Warrants.

As a result of the Amendment and Restatements, the May 2024 Series A Warrants and May 2024 Series B Warrants, as amended, no longer fail the indexation guidance under ASC 815, Derivatives and Hedging, and the fair value of the warrant liability at the amendment date, in the amount of $5.2 million, was reclassified to equity.

Lincoln Park Purchase Agreement

On June 17, 2025, the Company entered into a purchase agreement (the “Lincoln Park Purchase Agreement”) and a registration rights agreement (the “Registration Rights Agreement”) with Lincoln Park Capital Fund, LLC (“Lincoln Park”), pursuant to which the Company has the right, but not the obligation, to sell to Lincoln Park, and Lincoln Park committed to purchase up to $50.0 million of shares of the Company’s common stock, $0.001 par value per share. Such sales of common stock by the Company are subject to certain limitations and conditions set forth in the Lincoln Park Purchase Agreement including, but not limited to, the filing and effectiveness of a registration statement (a "Lincoln Park Registration Statement"). As of September 30, 2025, under the Lincoln Park Registration Statements, the resale of up to a total of 50,000,000 shares are reserved for issuance and sale under the Lincoln Park Purchase Agreement.

Under the Lincoln Park Purchase Agreement, on any business day selected by the Company over the 36-month period commencing on June 23, 2025 (the "Purchase Date"), the Company may direct Lincoln Park to purchase up to 300,000 shares of common stock on such Purchase Date, so long as the closing stock price on The Nasdaq Capital Market is not below $0.10 on the applicable Purchase Date (a “Regular Purchase”); provided, however, that (i) a Regular Purchase may be increased to up to 400,000 shares, if the closing sale price per share of the common stock on The Nasdaq Capital Market is not below $0.50 on the applicable Purchase Date; and (ii) a Regular Purchase may be increased to up to 500,000 shares, if the closing sale price per share of the common stock on The Nasdaq Capital Market is not below $0.75 on the applicable Purchase Date. In any case, Lincoln Park’s maximum obligation under any single Regular Purchase will not exceed $1.0 million. The above-referenced share amount limitations and closing sale price thresholds are subject to adjustment for any reorganization, recapitalization, non-cash dividend,

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stock split, reverse stock split or other similar transaction as provided in the Purchase Agreement. The purchase price per share for each such Regular Purchase will be 97% of the lesser of: (i) the lowest sale price for the common stock on The Nasdaq Capital Market on the date of sale, and (ii) the average of the three lowest closing sale prices for the common stock on The Nasdaq Capital Market during the 10 consecutive business days ending on the business day immediately preceding the purchase date.

The Company also has the right to direct Lincoln Park, on any business day on which the Company has properly submitted a Regular Purchase notice for the maximum amount the Company is then permitted to sell to Lincoln Park in such Regular Purchase, to purchase an additional amount of the common stock (an “Accelerated Purchase”) of additional shares based on criteria established in the Lincoln Park Purchase Agreement. The purchase price per share for each such Accelerated Purchase will be 96.5% of the lesser of: (i) t he volume weighted average price ("VWAP") during a specific time window on the Accelerated Purchase date as defined in the Lincoln Park Purchase Agreement, and (ii) the closing sale price of the Company’s common stock on The Nasdaq Capital Market on the same Accelerated Purchase date.

In addition to the Regular Purchase and Accelerated Purchase, the Company can sell to Lincoln Park an additional amount of common stock (an "Additional Accelerated Purchases"), which can be initiated multiple times on the same Additional Accelerated Purchase date. The purchase price per share for each such Additional Accelerated Purchase will be 96.5% of the lesser of: (i) t he VWAP during a specific time windows on the Additional Accelerated Purchase date as defined in the Lincoln Park Purchase Agreement, and (ii) the closing sale price of the Company’s common stock on The Nasdaq Capital Market on the same Additional Accelerated Purchase date.

The sales of shares of common stock to Lincoln Park through a Regular Purchase, an Accelerated Purchase and an Additional Accelerated Purchases, depend upon a variety of factors to be determined by the Company from time to time, including, among others, market conditions, the trading price of the common stock and determinations by the Company as to the appropriate sources of funding for the Company and its operations. The net proceeds under the Lincoln Park Purchase Agreement to the Company depend on the frequency and prices at which the Company sells shares of its stock to Lincoln Park.

In accordance with the Lincoln Park Purchase Agreement, the Company was required to pay Lincoln Park an initial commitment fee of $0.5 million, which was paid through the issuance of 1,612,903 shares of common stock on August 14, 2025. The initial commitment fee was recorded as a reduction to additional paid-in capital in the condensed consolidated balance sheet as of September 30, 2025. The Company has agreed to pay an additional commitment fee of $0.5 million, which it may elect to pay in cash or shares of its common stock, or a combination of cash and shares of its common stock, upon receipt of $25.0 million aggregate gross proceeds from sales of common stock to Lincoln Park under the Lincoln Park Purchase Agreement.

As of the nine months ended September 30, 2025, the Company issued 44,575,496 shares under the Lincoln Park Purchase Agreement for gross proceeds of approximately $19.6 million. The Company incurred approximately $50,000 for legal fees in connection with the Lincoln Park Purchase Agreement.

Outstanding Warrants

As of September 30, 2025, the Company had the following warrants outstanding:

| September 30, 2025 |
May 2024 Series A Warrants |  | 48,285 |
May 2024 Series B Warrants |  | 3,093,708 |
March 2025 Pre-Funded Warrants |  | 2,611,809 |
Total |  | 5,753,802 |

One share of common stock is issuable for each warrant upon exercise.

14. Stock-Based Compensation

Under the Company’s 2015 New Employee Incentive Plan (the “2015 Plan”), awards may only be granted to employees who were not previously an employee or director of the Company, or following a bona fide period of non-employment, as a material inducement to entering into employment with the Company. As of September 30, 2025, there were 76,025 shares of common stock remaining and available for future issuances under the 2015 Plan.

The Company’s 2020 Stock Incentive Plan (the “2020 Plan”), which replaced the Company’s 2014 Equity Incentive Plan, provides for the award or sale of shares of common stock (including restricted stock), the award of stock units and stock appreciation rights, and the grant of both incentive stock options to purchase common stock to directors, officers, employees and consultants of the Company. During the three months ended September 30, 2025, there was an additional 20,000,000 shares approved to be issued under the 2020 Plan. The 2020 Plan, as amended, provides for the issuance of up to 21,303,334 shares of common stock, plus the number of shares available for issuance is increased to the extent that awards granted under the 2020 Plan and the Company’s

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2014 Equity Incentive Plan are forfeited or expire (except as otherwise provided in the 2020 Plan). As of September 30, 2025, there were 10,005,151 shares remaining and available for future issuances under the 2020 Plan.

Generally, options issued under the 2020 Plan are subject to a two-year or four-year vesting schedule with 25% of the options vesting on the one year anniversary of the grant date followed by equal monthly installment vesting, and have a contractual term of 10 years.

A summary of stock option activity for the nine months ended September 30, 2025 is as follows:

|  | Options |  |  | Weighted Average Exercise Price |  |  | Weighted Average Remaining Contractual Term (years) |  |  | Aggregate Intrinsic Value (in thousands) |
Outstanding as of December 31, 2024 |  |  | 598,540 |  |  | $ | 7.08 |  |  |  | 9.00 |  |  | $ | — |
Granted |  |  | 10,800,137 |  |  | $ | 0.61 |  |  |  | — |  |  | $ | — |
Cancelled/forfeited/expired |  |  | (125,814 | ) |  | $ | 4.50 |  |  |  | — |  |  | $ | — |
Outstanding as of September 30, 2025 |  |  | 11,272,863 |  |  | $ | 0.91 |  |  |  | 9.76 |  |  | $ | 1,103 |
Vested and expected to vest at September 30, 2025 |  |  | 10,073,271 |  |  | $ | 0.94 |  |  |  | 9.75 |  |  | $ | 980 |
Exercisable at September 30, 2025 |  |  | 692,781 |  |  | $ | 5.15 |  |  |  | 8.99 |  |  | $ | 33 |

As of September 30, 2025, the total compensation cost related to non-vested stock options not yet recognized for all the Company’s plans is approximately $5.4 million, which is expected to be recognized as a result of vesting under service conditions over a weighted average period of 3.29 years.

Generally, restricted stock units represent the right to receive a certain number of shares of common stock subject to certain vesting conditions and other restrictions. The fair value of restricted stock units is determined by the closing market price on the grant date.

A summary of restricted stock unit activity for the nine months ended September 30, 2025 is as follows:

|  | Shares |  |  | Weighted Average Grant Date Fair Value |
Unvested as of December 31, 2024 |  |  | — |  |  | $ | — |
Granted |  |  | 2,823,857 |  |  | $ | 0.57 |
Vested |  |  | — |  |  | $ | — |
Cancelled/forfeited |  |  | — |  |  | $ | — |
Unvested as of September 30, 2025 |  |  | 2,823,857 |  |  | $ | 0.57 |

Restricted stock units granted during the nine months ended September 30, 2025 generally vest over a 36-month period upon satisfaction of service conditions. As of September 30, 2025, the total compensation cost related to non-vested restricted stock units not yet recognized for all the Company’s plans is approximately $1.5 million, which is expected to be recognized as a result of vesting under service conditions over a weighted average period of 2.75 years.

15. Segment Information

The Company operates under one reportable business segment to advance the development, manufacturing and commercialization of complex and innovative treatments for patients battling cancer and other life-threatening diseases. The determination of a single reportable business segment is consistent with the consolidated financial information regularly provided to the Company’s CODM. All of the Company's long-term assets and operations are located in the United States, and the measure of segment assets is reported on the condensed consolidated balance sheets as total assets. The Company’s CODM is its Chief Executive Officer, who reviews financial information presented on a consolidated basis for purposes of making operating decisions, allocating resources, and evaluating financial performance, including comparing actual results to budgets and forecasts to assess variances, identify trends, and guide strategic planning.

In addition to the significant expense categories included within the consolidated statements of operations, the below disaggregated amounts comprise significant research and development and general and administrative expenses. These expenses consist of (1) clinical, manufacturing and research contracts for research and development programs, (2) personnel-related expenses, including salaries, benefits and stock-based compensation, (3) professional fees, including third-party costs for goods and services such as lab supplies and contract research, and legal and other professional expenses, and (4) facility and other overhead expenses, including depreciation, occupancy, travel, insurance and other costs. Depreciation and amortization expense is consistent with those presented in the condensed consolidated statements of cash flows.

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|  | For the Three Months Ended September 30, |  |  | For the Nine Months Ended September 30, |
(in thousands) |  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Research and development |  |  |  |  |  |  |  |  |  |  |  |
Clinical, development and licensing expenses |  | $ | 1,362 |  |  | $ | 873 |  |  | $ | 2,698 |  |  | $ | 3,548 |
Personnel related expenses |  |  | 434 |  |  |  | 806 |  |  |  | 1,316 |  |  |  | 2,435 |
Professional fees |  |  | 391 |  |  |  | 830 |  |  |  | 737 |  |  |  | 1,412 |
Facility and other overhead expenses |  |  | 249 |  |  |  | 349 |  |  |  | 687 |  |  |  | 999 |
Total research and development |  |  | 2,436 |  |  |  | 2,858 |  |  |  | 5,438 |  |  |  | 8,394 |
General and administrative |  |  |  |  |  |  |  |  |  |  |  |
Personnel related expenses |  |  | 1,309 |  |  |  | 705 |  |  |  | 3,256 |  |  |  | 2,052 |
Professional fees |  |  | 1,744 |  |  |  | 1,281 |  |  |  | 3,748 |  |  |  | 3,585 |
Facility and other overhead expenses |  |  | 390 |  |  |  | 411 |  |  |  | 960 |  |  |  | 1,176 |
Total general and administrative |  | $ | 3,443 |  |  | $ | 2,397 |  |  | $ | 7,964 |  |  | $ | 6,813 |

16. Subsequent Events

Financing Related Transactions

As of September 30, 2025, the Company recorded a $6.4 million liability in accounts payable and accrued expenses due to the March 2025 Private Placement Purchasers. Such liability declined by $1.3 million from September 30, 2025 to October 27, 2025 due to 1) a $0.9 million reduction as a result of the reselling of securities acquired in the March 2025 Private Placement by certain March 2025 Private Placement Purchasers, which was recorded as a reduction of the liability that would have been settled in cash, with a corresponding increase to stockholders’ equity, and 2) a payment of $0.4 million to the March 2025 Private Placement Purchasers subsequent to September 30, 2025, with 0.6 million shares of the Company’s common stock returned and cancelled under the terms of the Letter Agreement.

On October 28, 2025, the Company entered into an amendment to the Letter Agreement and the Support Letters with certain March 2025 Private Placement Purchasers (the “Amendment Agreement”), pursuant to which (a) the Support Letters were terminated other than with respect to the participation rights granted therein, and (b) the repayment mechanism under the Letter Agreement was modified. As modified, the Company is no longer required to use 90% of the proceeds from any subsequent financing to repay the March 2025 Private Placement Purchasers. Instead, the Company is only required to retain sufficient funds in an interest bearing account to cover such repayment obligations and make such repayments upon request by any March 2025 Private Placement Purchaser who executed the Amendment Agreement until each such purchaser has received cash either from the Company or from reselling securities acquired in the March 2025 Private Placement in an amount equal to 115% of the purchase price such purchaser paid in the March 2025 Private Placement. If such requests are made, the requesting purchaser must return shares acquired in the March 2025 Private Placement at a value of $0.66 per share.

In addition, the Company issued approximately 3.3 million shares on the Lincoln Park Purchase Credit Agreement, raising an additional $1.9 million of capital through October 29, 2025.

Houston Lease

On October 16, 2025, the Company entered into a lease (the “Houston Lease”) with LG 1 Property Owner LP, pursuant to which the Company agreed to lease approximately 11,370 rentable square feet of space located at 6420 Levit Green Boulevard, Houston, Texas 77021. The Houston Lease is expected to commence on or about November 1, 2026. The Houston Lease provides for a monthly base rent of $58,745, which increases annually by approximately 3%, plus the Company’s share of the building’s direct expenses. The Houston Lease has an initial term of 120 calendar months.

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Item 2. Management’s Discussion and Analysis o f Financial Condition and Results of Operations

The following discussion and analysis should be read in conjunction with the unaudited financial information and the notes thereto included herein, as well as the “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our audited consolidated financial statements and notes thereto contained in our Annual Report on Form 10-K for the year ended December 31, 2024, as filed on March 31, 2025. This discussion contains forward-looking statements that involve risks and uncertainties. Our actual results and the timing of selected events could differ materially from those anticipated in these forward-looking statements as a result of several factors, including those set forth under the caption “Cautionary Note Regarding Forward-Looking Statements” in this Quarterly Report, as well as under “Part I – Item 1A - Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2024, in other subsequent filings with the Securities and Exchange Commission, and elsewhere in this Quarterly Report. These statements, like all statements in this Quarterly Report, speak only as of the date of this Quarterly Report (unless another date is indicated), and the Company undertakes no obligation to update or revise these statements in light of future developments.

Our Management’s Discussion and Analysis of Financial Condition and Results of Operations includes the following sections:

•
Overview that discusses our operating results and some of the trends that affect our business.
•
Results of Operations that includes a more detailed discussion of our revenue and expenses.
•
Liquidity and Capital Resources that discusses key aspects of our consolidated statements of cash flows, changes in our financial position and our financial commitments.

Overview

Plus Therapeutics is a U.S. pharmaceutical company developing targeted radiotherapeutics with advanced platform technologies for central nervous system (“CNS”) cancers. Our novel radioactive drug formulations and medical device and therapeutic candidates are designed to deliver safe and effective doses of radiation to tumors. To achieve this, we have developed innovative approaches to drug formulation, including encapsulating radionuclides such as rhenium isotopes with nanoliposomes and microspheres. Our formulations are intended to achieve elevated patient-absorbed radiation doses and extend retention times such that the clearance of the isotope occurs after significant and essentially complete radiation decay, which will contribute and provide less normal tissue/organ exposure and improved safety margins.

Traditional approaches to radiation therapy for cancer, such as external beam radiation, have many disadvantages including continuous treatment for four to six weeks (which is onerous for patients), that the radiation damages healthy cells and tissue, and that the amount of radiation delivered is very limited and, therefore, is frequently inadequate to fully destroy the cancer.

Our targeted radiotherapeutic platform and unique investigational drugs have the potential to overcome these disadvantages by directing higher, more powerful radiation doses at the tumor—and only the tumor—potentially in a single treatment. By minimizing radiation exposure to healthy tissues while simultaneously maximizing locoregional delivery and, thereby, efficacy, we hope to reduce the radiation toxicity for patients, improving their quality of life and life expectancy. Our radiotherapeutic platform, combined with advances in surgery, nuclear medicine, interventional radiology, and radiation oncology, affords us the opportunity to target a broad variety of cancer types.

Our lead radiotherapeutic candidate, REYOBIQ (rhenium (186 Re) obisbemeda), is designed specifically for CNS cancers including recurrent glioblastoma (“GBM”), leptomeningeal metastases (“LM”), and pediatric brain cancers (“PBC”) by direct localized delivery utilizing approved standard-of-care tissue access such as with convection-enhanced delivery (“CED”) and intraventricular brain (Ommaya reservoir) catheters. Our acquired radiotherapeutic candidate, Rhenium-188 NanoLiposome Biodegradable Alginate Microsphere (“188 RNL-BAM”), is designed to treat many solid organ cancers including primary and secondary liver cancers by intra-arterial injection.

Our cerebrospinal fluid cancer diagnostic portfolio known as the CNSide Platform is currently being utilized in the ReSPECT-LM clinical trial funded by the Cancer Prevention and Research Institute of Texas (“CPRIT”). In connection with our business plan for developing the CNSide Platform, we formed CNSide Diagnostics, LLC (“CNSide Diagnostics”), a wholly owned subsidiary of the Company, and our board of directors appointed a board of managers for CNSide Diagnostics. We are planning for the CNSide Cerebrospinal Fluid Tumor Cell Enumeration test (the “CNSide Test”), which is a laboratory developed test (“LDT”), to be re-introduced to the U.S. market starting in the fourth quarter of 2025. The laboratory for the CNSide Test in Houston, Texas has received a certificate of accreditation from the Centers for Medicare & Medicaid Services (CMS) which deems the lab compliant with Clinical Laboratory Improvement Amendments (“CLIA”) regulations. Furthermore, CNSide Diagnostics has signed a national agreement with UnitedHealthcare Insurance Company, effective September 15, 2025, covering over 51 million people throughout the United States, to provide the CNSide Test.

Our headquarters is located in Houston, Texas, in proximity to world-class cancer institutions and researchers.

Pipeline

Our most advanced investigational drug, REYOBIQ, is a patented radiotherapy potentially useful for patients with CNS and other cancers. We announced in March 2025 that the U.S. Food and Drug Administration (“FDA”) conditionally accepted the proprietary name REYOBIQ to be used by us for our proprietary rhenium (186 Re) obisbemeda. Preclinical study data describing the use of REYOBIQ

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for several cancer targets have been published in peer-reviewed journals and reported at a variety of medical society peer-reviewed meetings. Besides GBM, LM and PBC, REYOBIQ has been reported to have potential applications for head and neck cancer, ovarian cancer, breast cancer and peritoneal metastases.

The REYOBIQ technology was part of a licensed radiotherapeutic portfolio that we acquired from NanoTx, Corp. (“NanoTx”) on May 7, 2020. The licensed radiotherapeutic has been evaluated in preclinical studies for several cancer targets and we have an active $3.0 million award from U.S. National Institutes of Health/National Cancer Institute which is expected to provide financial support for the continued clinical development of REYOBIQ for recurrent GBM through the completion of a Phase 2 clinical trial, including enrollment of up to 55 patients.

REYOBIQ versus External Beam Radiation Therapy for Recurrent GBM

REYOBIQ is a novel injectable radiotherapy designed to deliver targeted, high dose radiation directly into GBM tumors in a safe, effective, and convenient manner that may ultimately prolong patient survival. REYOBIQ is composed of the radionuclide Rhenium-186 and a nanoliposomal carrier, and is infused in a highly targeted, controlled fashion, directly into the tumor via precision brain mapping and CED catheters. Potential benefits of REYOBIQ compared to standard external beam radiotherapy or external beam radiation therapy (“EBRT”) include:

•
The REYOBIQ radiation dose delivered to patients may be up to 20 times greater than what is possible with commonly used EBRT, which, unlike EBRT and proton beam devices, spares normal tissue and the brain from radiation exposure.
•
REYOBIQ can be visualized in real-time during administration, possibly giving clinicians better control of radiation dosing, distribution and retention.
•
REYOBIQ potentially more effectively treats a bulk tumor and microscopic disease that has already invaded healthy tissue.
•
REYOBIQ is infused directly into the targeted tumor by CED catheter insertion using MRI guided software to avoid critical patient neurological structures and neural pathways and also bypasses the blood brain barrier, which delivers the therapeutic product where it is needed. Importantly, it reduces radiation exposure to healthy cells, in contrast to EBRT, which passes through normal tissue to reach the tumor, continuing its path through the tumor, hence being less targeted and selective.
•
REYOBIQ is given during a single, short, in-patient hospital visit, and is available in all hospitals with nuclear medicine and neurosurgery, while EBRT requires out-patient visits five days a week for approximately four to six weeks.

ReSPECT-GBM Trial for Recurrent GBM

GBM affects approximately 15,000 patients annually in the U.S. and is the most common and lethal form of brain cancer. The average life expectancy with GBM is less than 24 months, with a one-year survival rate of 40% and a five-year survival rate of around 5%. There is no clear standard of care for recurrent GBM and the few currently approved treatments provide only marginal survival benefit and are associated with significant side effects, which limit dosing and prolonged use. Approximately 90% of patients experience GBM tumor recurrence at or near the original tumor location, yet there are no FDA-approved treatments in the recurrent or progressive setting that can significantly extend a patient’s life. GBM routinely presents with headaches, seizures, vision changes and other significant neurological complications, with a significant compromise in quality of life. Despite the best available medical treatments, the disease remains incurable. Even after efforts to manage the presenting signs and symptoms and completely resect the initial brain tumor, some microscopic disease almost always remains and tumor regrowth occurs within months. Complete surgical removal of GBM is usually not possible and GBM is often resistant or quickly develops resistance to most available current and investigational therapies. Today, the treatment of GBM remains a significant challenge and it has been nearly a decade since the FDA approved a new therapy for this disease, and these more recent approvals have not improved the overall survival (“OS”) for GBM patients over past decades, and a significant unmet medical need persists.

While EBRT has been shown to be safe and has temporary efficacy in many malignancies including GBM, typically at absorbed, fractionated radiation dose of ~30 Gray in GBM, this maximum possible administered dose is always limited by toxicity to the normal tissues surrounding the malignancy and because EBRT requires fractionation to manage toxicity and maximum EBRT limits are typically reached before long-term efficacy reached. Because of this limitation, EBRT cannot provide a cure or long-term control of GBM and GBM always recurs within months after EBRT. In contrast, locally delivered and targeted radiopharmaceuticals that precisely deliver radiation in the form of beta particles such as Iodine-131 for thyroid cancer, are known to be safe and effective and minimize exposure to normal cells and tissues especially with optimal administered dose and minimizing exposure to normal tissue. The locally delivered REYOBIQ is designed for and provides patient tolerability and safety. Though no REYOBIQ head-to-head trial with chemo, immune, EBRT or systemic radiopharmaceutical products have been conducted, patient tolerability and safety considerations have been reported as expected.

In September 2020, the FDA granted both orphan drug designation and Fast Track designations to REYOBIQ for the treatment of patients with GBM.

REYOBIQ is under clinical investigation in a Phase 1/2 multicenter, sequential cohort, open-label, volume and dose escalation study (“ReSPECT-GBM”) of the safety, tolerability, and distribution of REYOBIQ given by CED catheters to patients with recurrent or progressive malignant glioma after standard surgical, radiation, and/or chemotherapy treatment. The trial is funded through Phase 2 in large part by a National Institute of Health/National Cancer Institute grant.

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We completed Phase 1 of our ReSPECT-GBM Trial and are targeting full enrollment into Phase 2 by the end of 2026.

ReSPECT-LM Clinical Trials for LM

LM is a rare complication of cancer in which the disease spreads to the membranes (meninges) surrounding the brain and spinal cord. The incidence of LM is growing and occurs in approximately 5%, or more, of people with late-stage cancer, or 110,000 people in the U.S. each year. It is highly lethal with an average one-year survival of just 7%. All solid cancers, particularly breast, lung, GI, and melanoma, have the potential to spread to the leptomeninges.

The ReSPECT-LM Phase 1 clinical trial (ClinicalTrials.gov NCT05034497) was preceded with preclinical studies in which tolerance to doses of REYOBIQ as high as 1,075 Gy were shown in animal models with LM without significant observed toxicity. Furthermore, treatment led to a marked reduction in tumor burden in both C6 and MDA-231 LM models.

Upon receiving acceptance of our Investigational New Drug application and Fast Track designation by the FDA for REYOBIQ for the treatment of LM in November 2021, we initiated the trial and began screening patients for the ReSPECT-LM Phase 1 clinical trial in the fourth quarter of 2021.

ReSPECT-LM is a multi-center, sequential cohort, open-label, dose escalation study evaluating the safety, tolerability, and efficacy of a single-dose application of REYOBIQ administered through intrathecal infusion to the ventricle of patients with LM after standard surgical, radiation, and/or chemotherapy treatment. The primary endpoint of the study is the incidence and severity of adverse events and dose limiting toxicities, together with determining the maximum tolerated and recommended Phase 2 dose. Full enrollment in the Phase 1 trial was achieved at the end of 2024, and we announced the trial completion on February 26, 2025. Trial closeout procedures are now taking place including final data review and monitoring, and a clinical study report and manuscript will be prepared.

On September 19, 2022, we entered into a Cancer Research Grant Contract (the “CPRIT Contract”), effective as of August 31, 2022, with CPRIT, pursuant to which CPRIT provides us a grant of up to $17.6 million (the “CPRIT Grant”) over a three-year period to fund the continued development of REYOBIQ for the treatment of patients with LM through Phase 2 of the ReSPECT-LM clinical trial. The CPRIT Grant is subject to customary CPRIT funding conditions, including, but not limited to, a matching fund requirement (one dollar from us for every two dollars awarded by CPRIT), revenue sharing obligations upon commercialization of REYOBIQ based on specific dollar thresholds until CPRIT receives the aggregate amount of 400% of the proceeds awarded under the CPRIT Grant, and certain reporting requirements. As of September 30, 2025, we had received approximately $14.3 million in milestone payments under the CPRIT Contract.

Interim results show that a single treatment with REYOBIQ resulted in a consistent decreased cerebrospinal fluid (“CSF”) tumor cell count/ml and is tolerated by all LM patients. REYOBIQ is an outpatient administration and treatment and is easily and safely administered through a standard intraventricular catheter (Ommaya Reservoir), distributed promptly throughout the CSF, and with durable retention in the leptomeninges at least through day seven. All patients have shown well tolerated prompt and durable REYOBIQ distribution throughout the subarachnoid space.

Our ReSPECT LM Multi-dose Phase 1/2 Study is currently enrolling patients.

ReSPECT-PBC Clinical Trial for Pediatric Brain Cancer

The average annual age adjusted mortality rate for children aged 0-14 for malignant brain (and other CNS) tumors is 0.71/100,000, making it the most common cause of death and cancer death in this age group. The 2021 World Health Organization Classification of CNS Tumors classifies gliomas, glioneuronal tumors, and neuronal tumors into six different families: (1) adult-type diffuse gliomas; (2) pediatric-type diffuse low-grade gliomas; (3) pediatric-type diffuse high-grade gliomas (“HGG”); (4) circumscribed astrocytic gliomas; (5) glioneuronal and neuronal tumors; and (6) ependymomas.

In August 2021, we announced plans for treating pediatric brain cancer at the 2021 American Association of Neurological Surgeons Annual Scientific Meeting. In July 2021, we reported that we received FDA feedback pertaining to a pre-Investigational New Drug Application (“IND”) meeting briefing package in which the FDA stated that we are not required to perform any additional preclinical or toxicology studies.

Pediatric high-grade gliomas can be found almost anywhere within the CNS; however, they are most commonly found within the supratentorium. The highest incidence of supratentorial, high-grade gliomas in pediatrics appears to occur in children aged 15 to 19 years, with a median age of approximately nine years. Overall, pediatric high-grade glioma confers a three-year progression free survival (“PFS”) of 11 ± 3% and three-year OS of 22 ±5%. One-year PFS is as low as 40% in recent trials. Ependymomas are slow-growing central nervous system tumors that involve the ventricular system. Diagnosis is based on MRI and biopsy and survival rate depends on tumor grade and how much of the tumor can be removed. Grade II pathology was associated with significantly improved OS compared to Grade III (anaplastic) pathology (five-year OS = 71 ± 5% vs. 57 ± 10%; p = 0.026). Gross total resection compared to subtotal resection was associated with significantly improved OS (five-year OS = 75 ± 5% vs. 54 ± 8%; p = 0.002).

Overall, pediatric HGG and ependymoma are extremely difficult-to-treat pediatric brain tumors, frequently aggressive, and in recurrent settings, carry an extremely poor prognosis.

Effective September 1, 2024, we entered into an agreement with the Department of Defense office of the Congressionally Directed Medical Research Programs to receive a $3.0 million fund for research and development purposes (“DoD Award”) over a three-year

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period. The DoD Award will be used to support the planned expansion of our clinical trial for pediatric brain cancer. We anticipate beginning enrollment for our Phase 1 ReSPECT-PBC clinical trial in 2025.

On June 25, 2025, we announced that the FDA cleared its Investigational New Drug ("IND") application (No. 168178) for REYOBIQ for the treatment of pediatric patients with supratentorial recurrent, refractory, or progressive high-grade glioma ("HGG") and ependymoma. The Phase 1/2a trial is a two-part, single-arm, prospective study aimed at determining the maximum tolerated dose ("MTD"), safety, and tolerability of REYOBIQ in pediatric patients aged 6 to 21 years (with consideration for patients up to 25 years on a case-by-case basis).

Key elements of the trial design include:

•
Phase 1a/b (dose escalation): This phase will enroll an estimated 24 patients using a modified 3+3 dose escalation scheme to establish the MTD and recommended Phase 2 dose ("RP2D"). Safety assessment and alignment with the FDA will occur at defined intervals.
•
Phase 2a: This phase will enroll approximately 32 patients (12 with ependymoma and 20 with HGG) at the RP2D to assess efficacy.
•
We anticipate to begin enrollment in our ReSPECT-PBC clinical trial before the end of 2025.

Rhenium-188 NanoLiposome Biodegradable Alginate Microsphere Technology

In January 2022, we announced that we licensed Biodegradable Alginate Microsphere (“BAM”) patents and technology from The University of Texas Health Science Center at San Antonio (“UTHSCSA”) to expand our tumor targeting capabilities and precision radiotherapeutics pipeline. We intend to combine our Rhenium NanoLiposome technology with the BAM technology to create a novel radioembolization technology. Initially, we intend to utilize the Rhenium-188 isotope, 188 RNL-BAM for the intra-arterial embolization and local delivery of a high dose of targeted radiation for a variety of solid organ cancers such as hepatocellular cancer, hepatic metastases, pancreatic cancer and many others.

Preclinical data from an ex vivo embolization experiment in which Technetium99m-BAM was intra-arterially delivered to a bovine kidney perfusion model was presented at the Society of Interventional Radiology Annual Scientific Meeting. The study concluded that the technology required for radiolabeling BAM could successfully deliver, embolize and retain radiation in the target organ. 188 RNL-BAM is a preclinical investigational device we intend to further develop and move into clinical trials. Specifically, in 2022 we transferred the 188 RNL-BAM technology from UTHSCSA, and began planning to develop the product and complete early preclinical studies to support a future FDA IND submission. Our intended initial clinical target is liver cancer which is the sixth most common and third deadliest cancer worldwide. It is a rare disease with increasing U.S. annual incidence (42,000) and deaths (30,000).

The FDA has informed us that 188 RNL-BAM will be regulated as a medical device under the FDCA.

The CNSide FORESEE Trial

The CNSide Platform consists of four LDTs used for treatment selection and treatment monitoring of patients with LM. The CNSide Platform facilitates tumor cell detection/enumeration and biomarker identification using cellular assays (immunocytochemistry (ICC) and fluorescence in situ hybridization (FISH)) and molecular assays (next-generation sequencing (NGS)). The CNSide Test is currently being used in the ReSPECT-LM trial as an exploratory endpoint.

Since acquiring the CNSide Platform in 2024, we have established infrastructure to support a scalable and centralized testing laboratory in Houston, TX that will service the U.S. market. We have been executing on our commercial market access strategy, which includes prioritized state licensure, proprietary reimbursement codes, commercial and government payor coverage, and value-based pricing to optimize revenue. We anticipate introducing the CNSide Platform first in Texas in the second half of 2025, followed rapidly by expansion into additional states in 2026. In parallel, additional expanded CNS testing capabilities are also expected to roll out over the next year.

When the CNSide CSF Assay Platform was previously commercially available, market acceptance and adoption were widespread, with several national and regional commercial payor agreements in place and the test in regular use at major cancer centers across the U.S. We are now in contact with the legacy payors and healthcare providers in anticipation of the planned 2025 launch, and later this year will be expanding those contacts to support a 50-state strategy. Finally, we have hired experienced leadership with expertise in the development and commercialization of clinical diagnostic technologies on a large scale.

Recent Developments

Recent Financings

Refer to the “Liquidity and Capital Resources” section below for information on our recent financings.

Financing Related Transactions

As of September 30, 2025, we recorded a $6.4 million liability in accounts payable and accrued expenses due to the March 2025 Private Placement Purchasers. Such liability declined by $1.3 million from September 30, 2025 to October 27, 2025 due to 1) a $0.9 million reduction as a result of the reselling of securities acquired in the March 2025 Private Placement by certain March 2025 Private Placement Purchasers, which was recorded as a reduction of liability that would have been settled in cash, with a corresponding increase to

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stockholders’ equity, and 2) a payment of $0.4 million to the March 2025 Private Placement Purchasers subsequent to September 30, 2025, with 0.6 million shares of the Company’s common stock returned and cancelled under the terms of the Letter Agreement.

On October 28, 2025, we entered into an amendment to the Letter Agreement and the Support Letters with certain March 2025 Private Placement Purchasers (the “Amendment Agreement”), pursuant to which (a) the Support Letters were terminated other than with respect to the participation rights granted therein, and (b) the repayment mechanism under the Letter Agreement was modified. As modified, we are no longer required to use 90% of the proceeds from any subsequent financing to repay the March 2025 Private Placement Purchasers. Instead, we are only required to retain sufficient funds in an interest bearing account to cover such repayment obligations and make such repayments upon request by any March 2025 Private Placement Purchaser who executed the Amendment Agreement until each such purchaser has received cash either from us or from reselling securities acquired in the March 2025 Private Placement in an amount equal to 115% of the purchase price such purchaser paid in the March 2025 Private Placement. If such requests are made, the requesting purchaser must return shares acquired in the March 2025 Private Placement at a value of $0.66 per share.

In addition, we issued approximately 3.3 million shares on the Lincoln Park Purchase Credit Agreement, raising an additional $1.9 million of capital through October 29, 2025.

Houston Lease

On October 16, 2025, we entered into a lease (the “Houston Lease”) with LG 1 Property Owner LP, pursuant to which we agreed to lease approximately 11,370 rentable square feet of space located at 6420 Levit Green Boulevard, Houston, Texas 77021. The Houston Lease is expected to commence on or about November 1, 2026. The Houston Lease provides for a monthly base rent of $58,745, which increases annually by approximately 3%, plus our share of the building’s direct expenses. The Houston Lease has an initial term of 120 calendar months.

Results of Operations

Grant Revenue

We recognized $1.4 million and $3.8 million, and $1.5 million and $4.4 million of grant revenue during the three and nine months ended September 30, 2025 and 2024, respectively, which represents CPRIT’s share of the costs incurred for our rhenium (186 Re) obisbemeda development for the treatment of patients with LM.

Research and development expenses

Research and development expenses include costs associated with the design, development, testing, and enhancement of our product candidates, payment of regulatory fees, laboratory supplies, preclinical studies, and clinical studies.

The following table summarizes the components of our research and development expenses for the three and nine months ended September 30, 2025 and 2024 (in thousands):

|  | Three Months Ended September 30, |  |  | Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Research and development |  | $ | 2,425 |  |  | $ | 2,844 |  |  | $ | 5,423 |  |  | $ | 8,343 |
Stock-based compensation |  |  | 11 |  |  |  | 14 |  |  |  | 15 |  |  |  | 51 |
Total research and development expenses |  | $ | 2,436 |  |  | $ | 2,858 |  |  | $ | 5,438 |  |  | $ | 8,394 |

Research and development expenses decreased by approximately $0.4 million during the three months ended September 30, 2025 as compared to the same period in 2024. The decrease was due primarily to a decrease of $0.4 million in development expenses, a decrease of $0.4 million in compensation expense, a decrease of $0.4 million in professional research and development services, and a decrease of $0.1 million in depreciation expense. These decreases were partially offset by an increase of $0.5 million in licensing expenses and an increase of $0.4 million in diagnostics.

Research and development expenses decreased by approximately $3.0 million during the nine months ended September 30, 2025 as compared to the same period in 2024. The decrease was due primarily to a decrease of $1.3 million in clinical expenses, a decrease of $1.1 million in compensation expense, a decrease of $0.7 million in professional services, a decrease of $0.3 million in development expenses, a decrease of $0.2 million in depreciation expense and a decrease of $0.1 million in travel costs. These decreases were partially offset by an increase of $0.4 million in diagnostics, and $0.3 million in licensing expenses.

We expect aggregate research and development expenses to increase during the remainder of 2025 as compared to the corresponding comparable period in 2024 as we commence the ReSPECT-LM dose optimization trial for REYOBIQ and prepare for the launch of the CNSide Test.

General and administrative expenses

General and administrative expenses include costs for administrative personnel, legal and other professional expenses, and general corporate expenses. The following table summarizes the general and administrative expenses for the three and nine months ended September 30, 2025 and 2024 (in thousands):

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|  | Three Months Ended September 30, |  |  | Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
General and administrative |  | $ | 2,927 |  |  | $ | 2,286 |  |  | $ | 7,152 |  |  | $ | 6,442 |
Stock-based compensation |  |  | 516 |  |  |  | 111 |  |  |  | 812 |  |  |  | 371 |
Total general and administrative expenses |  | $ | 3,443 |  |  | $ | 2,397 |  |  | $ | 7,964 |  |  | $ | 6,813 |

General and administrative expenses increased by $1.0 million during the three months ended September 30, 2025, as compared to the same period in 2024, primarily due to an increase of $0.6 million in compensation expense, an increase of $0.3 million in legal and professional fees, and an increase of $0.1 million in accounting expenses.

General and administrative expenses increased $1.2 million during the nine months ended September 30, 2025, as compared to the same period in 2024, primarily due to an increase of $1.3 million in compensation expense, partially offset by a decrease of $0.1 million in legal and professional services.

We expect general and administrative expenditures to increase during the remainder of 2025 as compared to the corresponding comparable period in 2024 as we work towards the commercial launch of the CNSide Test, which will require an increase in administrative and sales headcount.

Stock-based compensation expense

Stock-based compensation expense includes charges related to equity awards issued to employees, directors and non-employees. We measure stock-based compensation expense based on the grant-date fair value of any awards granted to our employees. Such expense is recognized over the requisite service period.

The following table summarizes the components of our stock-based compensation expenses for the three and nine months ended September 30, 2025 and 2024 (in thousands):

|  | Three Months Ended September 30, |  |  | Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Research and development |  | $ | 11 |  |  | $ | 14 |  |  | $ | 15 |  |  | $ | 51 |
General and administrative |  |  | 516 |  |  |  | 111 |  |  |  | 812 |  |  |  | 371 |
Total stock-based compensation |  | $ | 527 |  |  | $ | 125 |  |  | $ | 827 |  |  | $ | 422 |

Our stock-based compensation expense is impacted by grants of equity awards, the vesting schedule of such grants, as well as the grant date fair value of equity awards. Stock-based compensation expense increased during the three and nine months ended September 30, 2025 as compared to the same periods in 2024 primarily due to an increase in the number of awards granted, which was partially offset by a decrease in the grant date fair value of equity awards granted.

Financing items

The following table summarizes non-operating income and expenses for the three and nine months ended September 30, 2025 and 2024 (in thousands):

|  | Three Months Ended September 30, |  |  | Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Interest income |  | $ | 59 |  |  | $ | 80 |  |  | $ | 87 |  |  | $ | 219 |
Interest expense |  |  | — |  |  |  | (61 | ) |  |  | (548 | ) |  |  | (122 | )
Financing expenses |  |  | — |  |  |  | — |  |  |  | (3,061 | ) |  |  | (3,545 | )
Change in fair value of derivative instruments |  |  | — |  |  |  | 960 |  |  |  | (2,631 | ) |  |  | 5,654 |
Warrant issuance costs |  |  | — |  |  |  | (54 | ) |  |  | (964 | ) |  |  | (486 | )
Total |  | $ | 59 |  |  | $ | 925 |  |  | $ | (7,117 | ) |  | $ | 1,720 |

Interest income decreased for the three and nine months ended September 30, 2025 compared with the same period in 2024 primarily due to reduced accreted income on our available-for-sale securities in 2024 and a lower interest rate environment in 2025.

The decrease in interest expense for the three months ended September 30, 2025 as compared to the same period in 2024 was due to the January 2025 payoff of the Pershing Credit Facility. The increase in interest expense for the nine months ended September 30, 2025 as compared to the same period in 2024 was due to interest expense incurred in connection with the Funding Notes and Exchange Notes issued in February 2025, partially offset by the January 2025 payoff of the Pershing Credit Facility.

The decrease in financing expenses for the nine months ended September 30, 2025 as compared to the same period in 2024 was primarily due to the March 2025 PIPE and May 2024 PIPE transactions.

The change in the fair value of the derivative instruments for the three months ended September 30, 2025 as compared to the same period in 2024 was due to the March 2025 Private Placement and May 2024 Private Placement and accompanying warrants issued in both financings. The change in the fair value of the derivative instruments for the nine months ended September 30, 2025 as compared

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to the same period in 2024 was primarily due to the March 2025 Private Placement (specifically the liability classified March 2025 Series B Warrants, which were remeasured immediately prior to exercise, before being reclassified as equity), offset by the May 2024 Private Placement (specifically the May 2024 Series A Warrants and May 2024 Series B Warrants, which were initially classified as liabilities before being reclassified as equity).

The decrease in warrant issuance costs for the three months ended September 30, 2025 as compared to the same period in 2024, was due to warrant issuance costs related to the May 2024 Private Placement. The increase in the warrant issuance costs for the nine months ended September 30, 2025 as compared to the same period in 2024 was due to the warrant issuance costs from the March 2025 Private Placement and May 2024 Private Placement.

Liquidity and Capital Resources

Short-term and long-term liquidity

The following is a summary of our key liquidity measures at September 30, 2025 and December 31, 2024 (in thousands):

|  | September 30, 2025 |  |  | December 31, 2024 |
Cash and cash equivalents |  | $ | 13,289 |  |  | $ | 76 |
Current assets |  | $ | 17,586 |  |  | $ | 5,259 |
Current liabilities |  |  | 13,616 |  |  |  | 15,551 |
Working capital |  | $ | 3,970 |  |  | $ | (10,292 | )

We incurred net losses of $16.7 million for the nine months ended September 30, 2025. We have an accumulated deficit of $510.2 million as of September 30, 2025. Additionally, we used net cash of $14.5 million to fund our operating activities for the nine months ended September 30, 2025. These factors raise substantial doubt about our ability to continue as a going concern.

To date, our operating losses have been funded primarily from outside sources of invested capital, from issuance of our common and preferred equity, proceeds from our now-repaid in full term loan with Oxford Finance, LLC (“Oxford”), our line of credit facility with Pershing LLC and grant funding. We have had, and will continue to have, an ongoing need to raise additional cash from outside sources to fund our future clinical development programs and other operations, and commercialize the CNSide Test. There can be no assurance that we will be able to continue to raise additional capital in the future. Our inability to raise additional cash would have a material and adverse impact on our operations and ability to satisfy our obligations.

February 2025 SPEA

On February 13, 2025 (the “February 2025 SPEA Closing Date”), we entered into a securities purchase and exchange agreement (the “February 2025 SPEA”) with certain existing accredited investors. Pursuant to the February 2025 SPEA, on the February 2025 SPEA Closing Date we issued secured convertible promissory notes (the “Funding Notes”) in the aggregate principal amount of $3.3 million together with common stock purchase warrants (the “February 2025 Warrants”) to purchase 3,002,009 shares of our common stock at an exercise price of $1.12 per share. The aggregate purchase price for the Funding Note and February 2025 Warrants was approximately $3.7 million and included payment of $0.125 per February 2025 Warrant in accordance with the listing rules of Nasdaq.

Exchange Notes

The May 2024 Purchase Agreement (as described below) included certain limitations and restrictions on our ability to issue securities and provided the May 2024 Private Placement Purchasers other than our directors and executive officers (the “Outside Investors”) participation rights in future equity and equity-linked offerings of securities, subject to certain limited exceptions (the “Financing Restrictions”). On the February 2025 SPEA Closing Date, pursuant to the February 2025 SPEA, we issued to the Outside Investors secured convertible promissory notes in the aggregate amount of $3.2 million (the “Exchange Notes”) in exchange for cancellation of the 3,543,247 May 2024 Series A Warrants held by them, and the Outside Investors entered into a second amendment to the May 2024 Purchase Agreement to eliminate the Financing Restrictions.

As described below, we repurchased the Funding Notes and issued common stock and warrants for cancellation of the Exchange Notes in connection with the March 2025 Private Placement.

March 2025 Private Placement

On March 4, 2025, we entered into a securities purchase agreement (the “March 2025 Purchase Agreement”) with accredited investors, including certain of our existing stockholders, identified on the signature page thereto (collectively, the “March 2025 Private Placement Purchasers”) for a private placement of securities (the “March 2025 Private Placement”) for gross proceeds of approximately $15.0 million. Pursuant to the March 2025 Purchase Agreement, we issued an aggregate of 4,069,738 shares (the “March 2025 Private Placement Shares”) of our common stock and 23,972,400 Pre-Funded Warrants, with each March 2025 Private Placement Share or Pre-Funded Warrant accompanied by (i) a Series A common warrant (the “March 2025 Series A Warrants”) to purchase one share of common stock and (ii) one Series B common warrant (the “March 2025 Series B Warrants”) to purchase one share of common stock.

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The combined purchase price of $0.66 for each March 2025 Private Placement Share or $0.659 for each Pre-Funded Warrant in the March 2025 Private Placement, together with one accompanying March 2025 Series A Warrant and one accompanying March 2025 Series B Warrant, represented the applicable “Minimum Price” in accordance with Listing Rule 5635(d) of Nasdaq.

The initial exercise price of each March 2025 Series A Warrant is $1.32 per share of common stock. The March 2025 Series A Warrants are exercisable only following stockholder approval and expire five (5) years thereafter. The March 2025 Series A Warrants are subject to certain price reset, share combination event and anti-dilution provisions which, if triggered, provide that the number of shares issuable upon exercise of the March 2025 Series A Warrants will downward adjust, subject to the Floor Price, and the number of shares issuable upon exercise therefor will increase such that the aggregate exercise price remains unchanged.

The initial exercise price of each March 2025 Series B Warrant is $1.98 per share of common stock. The March 2025 Series B Warrants are exercisable only following stockholder approval and expire two and one-half (2.5) years thereafter. The March 2025 Series B Warrants are subject to certain price reset and share combination event provisions which, if triggered, provide that the number of shares issuable upon exercise of the March 2025 Series B Warrants will downward adjust, subject to the Floor Price, and the number of shares issuable upon exercise therefor will increase such that the aggregate exercise price remains unchanged. In addition, the March 2025 Series B Warrant alternative cashless exercise provision provides that the March 2025 Series B Warrant can be exercised without further payment to us and for three times the number of shares of common stock then subject to the March 2025 Series B Warrant.

Of the securities issued in the March 2025 Private Placement, 3,077,270 shares of Common Stock, 19,650,000 shares of March 2025 Pre-Funded Warrants in lieu thereof, and the accompanying 22,727,270 March 2025 Series A Warrants and 22,727,270 March 2025 Series B Warrants, were issued in consideration of new capital subscriptions, and 992,468 shares of Common Stock, 4,322,400 March 2025 Pre-Funded Warrants in lieu thereof, and the accompanying 5,314,870 March 2025 Series A Warrants and 5,314,870 March 2025 Series B Warrants, were issued in exchange for the cancelation of the Exchange Notes.

The March 2025 Private Placement closed on March 7, 2025. The aggregate gross proceeds at the closing were approximately $15.0 million, before deducting $1.4 million of expenses payable by us.

On May 2, 2025, our stockholders approved, among other things, the March 2025 Series A Warrants and March 2025 Series B Warrants and an amendment of our Certificate of Incorporation, as amended, to increase the authorized share capital to an amount sufficient to cover the shares of common stock issuable upon the exercise of the March 2025 Series A Warrants and March 2025 Series B Warrants. As part of the March 2025 Series A Warrants and March 2025 Series B Warrants agreement, the exercise price of the March 2025 Series A Warrants and March 2023 Series B Warrants were reset on May 19, 2025 to $0.4373 per share. Prior to modification of the March 2025 Series B Warrants as part of the Letter Agreement (as further described below), certain March 2025 Series B Warrants were cashless exercised for the issuance of 21,482,492 shares of common stock. The liability classified March 2025 Series B Warrants were remeasured immediately prior to exercise, which resulted in a $3.8 million gain on the change in fair value for the nine months ended September 30, 2025, and a $0.8 million credit to additional paid-in-capital.

Letter Agreement

On June 17, 2025, the Company and the Purchasers entered into a letter agreement (the “Letter Agreement”) with each of the Purchasers in an effort to, among other items, minimize the dilutive impact of the March 2025 Private Placement. The Letter Agreement extinguished the March 2025 Series A Warrants, modified the March 2025 Series B Warrants, and provided for the return of Private Placement Shares and Pre-Funded Warrants, as further discussed in the following paragraphs.

As part of the Letter Agreement, all March 2025 Series A Warrants were cancelled, which resulted in a $2.7 million gain on change in fair value recorded as capital contribution to additional paid-in capital, as the extinguishment was deemed equivalent to a capital contribution by existing shareholders of the Company.

As part of the same transaction, the March 2025 Series B Warrants were amended ("Amended March 2025 Series B Warrants"), to (a) reduce the overall number of March 2025 Series B Warrant Shares issuable upon exercise of the Series B Warrants to an aggregate of up to 35,536,380 Series B Warrant Shares, (b) reduce the alternative cashless exercise ratio in such March 2025 Series B Warrants from 3:1 to 1:1, and (c) remove provisions contained in the March 2025 Series B Warrants that would otherwise reduce the Company’s stockholders’ equity. As a result of the Letter Agreement, the Amended March 2025 Series B Warrants no longer fail the indexation guidance under ASC 815, Derivatives and Hedging, and the fair value of the warrant liability, in the amount of $11.0 million was reclassified to equity. Immediately prior to reclassification, the March 2025 Series B Warrant liability was remeasured, and $4.5 million was recorded as a capital contribution to additional paid-in capital, as the modification of the March 2025 Series B Warrants was deemed equivalent to a capital contribution by existing shareholders of the Company. After the June 17, 2025 modification, 34,794,54 Amended March 2025 Series B Warrants were cashless exercised.

Lastly, in conjunction with the Letter Agreement, each of the March 2025 Private Placement Purchasers agreed to return an aggregate of 12,241,986 Private Placement Shares and Pre-Funded Warrants issuable for an aggregate of 10,633,650 Pre-Funded Warrant Shares, held by them as of the date of the Letter Agreement, upon request of the Company (the "Letter Agreement Repurchase Option"), which were issued pursuant to the March 2025 Private Placement Purchase Agreement for a value of $0.66 per Private Placement Share and $0.659 per Pre-Funded Warrant. In exchange therefor, the Company agreed to repay the March 2025 Private Placement Purchasers holding such securities 115% of such value, using 90% of the proceeds from any capital raised by the Company subsequent to July 1, 2025. The Company and each of the March 2025 Private Placement Purchasers also agreed to waive any restrictions on subsequent equity sales and variable rate transactions contained in March 2025 Private Placement Purchase Agreement to allow for such repayment.

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During the three and nine months ended September 30, 2025, we paid the March 2025 Private Placement Purchasers $2.3 million and 3,472,740 shares were returned and cancelled under the terms of the Letter Agreement.

Support Letters

On July 11, 2025, we and certain March 2025 Private Placement Purchasers party to the Letter Agreement entered into that certain letter of support (the “Support Letters”) to modify certain portions of the Letter Agreement as between us and each of such March 2025 Private Placement Purchasers. In the event that we reasonably believe that, within the 30 days (the “Modification Period”) prior to the end of any fiscal quarter, we will have stockholders’ equity in an amount below $3.0 million as of the end of such fiscal quarter (the “Potential Equity Deficiency”), the Subsequent Financing Percentage (as defined in the Letter Agreement) shall be modified from 90% to 50% for any Subsequent Financing (as defined in the Letter Agreement) that occurs during the Modification Period pursuant to the Lincoln Park Purchase Agreement. Upon the end of the Modification Period, the Subsequent Financing Percentage shall be reverted to 90%, and such percentage shall apply to all Subsequent Financings, including all Subsequent Financings pursuant to the Lincoln Park Purchase Agreement. In the event we desire to trigger the modification of the Subsequent Financing Percentage, we agree to supply the purchaser who executed a Support Letter with a pro forma balance sheet to evidence its reasonable belief of the Potential Equity Deficiency approximately 30 days prior to each end of fiscal quarter once the books for prior months are closed. In accordance with the Support Letters, we made a cash payment of $0.5 million to each purchaser for a total cash payment of $2.3 million, which was recorded as a reduction to additional paid-in capital in the condensed consolidated balance sheet as of September 30, 2025. Such payment counted as cash received by the purchaser towards its Maximum Amount. Each Support Letter also grants the purchaser party to the letter a participation right in certain future financings of ours for a period of 12 months.

First Amendment to the February 2025 SPEA

In connection with the March 2025 Purchase Agreement, we entered into that certain First Amendment to the February 2025 SPEA (the “First Amendment”). The February 2025 SPEA included certain limitations and restrictions on our ability to issue securities and provided the investors participation rights in future equity and equity-linked offerings of securities, subject to certain limited exceptions (the “New Financing Restrictions”). Pursuant to the First Amendment, subject to consummation of the March 2025 Private Placement, we agreed to repurchase from the Investors $3.4 million in principal amount of the Funding Notes and accrued interest, along with the February 2025 Warrants issued pursuant to the February 2025 SPEA for an aggregate purchase price of $4.2 million. In exchange for the repurchase by us of the Funding Notes and February 2025 SPEA Warrants, the February 2025 Purchasers agreed to consent to the March 2025 Private Placement and eliminate the New Financing Restrictions.

May 2024 Private Placement

In May 2024, we entered into a securities purchase agreement (the “May 2024 Purchase Agreement”), which was subsequently amended, with certain investors, including certain of the our directors and executive officers (the “May 2024 Private Placement Purchasers”), whereby we issued and sold in a private placement (the “May 2024 Private Placement”): (i) 3,591,532 shares of common stock or, at the election of each investor, Pre-Funded warrants (“May 2024 Pre-Funded Warrants”) to purchase shares of common stock exercisable immediately at an exercise price of $0.001 per share. Each share or May 2024 Pre-Funded Warrant was accompanied by (i) a Series A common warrant (“May 2024 Series A Warrants”) to purchase one share of common stock, for an aggregate of 3,591,532 Series A Warrants, and (ii) one Series B common warrant (“May 2024 Series B Warrants”) to purchase one share of common stock, for an aggregate of 3,591,532 May 2024 Series B Warrants. At the closing of the May 2024 Private Placement, we received net proceeds of approximately $7.3 million.

Lincoln Park Purchase Agreement

On June 17, 2025, we entered into a purchase agreement (the “Lincoln Park Purchase Agreement”) and a registration rights agreement pursuant to which Lincoln Park Capital Fund (“Lincoln Park”) committed to purchase up to $50.0 million of shares of our common stock. Under the terms and subject to the conditions of the Lincoln Park Purchase Agreement, we have the right, but not the obligation, to sell to Lincoln Park, and Lincoln Park is obligated to purchase up to $50.0 million of shares of our common stock. Sales of common stock by us are subject to certain limitations, and can occur from time to time, at our sole discretion, over the 36-month period commencing on June 23, 2025, subject to the satisfaction of certain conditions. Actual sales of shares of common stock to Lincoln Park under the Lincoln Park Purchase Agreement depend on a variety of factors to be determined by us from time to time, including, among others, market conditions, the trading price of the common stock and our determinations as to the appropriate sources of funding for the Company and its operations. As consideration for Lincoln Park’s irrevocable commitment to purchase shares of our common stock upon the terms of and subject to satisfaction of the conditions set forth in the Lincoln Park Purchase Agreement,

On June 23, 2025, a registration statement (the “Initial Registration Statement”) was declared effective covering the resale of up to 17,000,000 shares of our common stock. On August 14, 2025, a registration statement (the “Second Registration Statement”) was declared effective covering the resale of up to 33,000,000 shares of our common stock.

In accordance with the Lincoln Park Purchase Agreement, we were required to pay Lincoln Park an initial commitment fee of $0.5 million, which was paid through the issuance of 1,612,903 shares of common stock on August 14, 2025. The initial commitment fee was recorded as a reduction to additional paid-in capital in the condensed consolidated balance sheet as of September 30, 2025. An additional commitment fee of $0.5 million will be paid in cash or shares of common stock, or a combination of cash and shares of common stock, if and when we sell over $25.0 million of our common stock under the Lincoln Park Purchase Agreement.

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As of the nine months ended September 30, 2025, we issued 44,575,496 shares under the Lincoln Park Purchase Agreement for gross proceeds of approximately $19.6 million. The Company incurred approximately $50,000 for legal fees in connection with the Lincoln Park Purchase Agreement.

Subsequent to September 30, 2025, we issued 3.3 million shares under the Lincoln Park Purchase Agreement, raising an additional $1.9 million of capital through October 29, 2025.

CPRIT Grant

On September 19, 2022, we entered into the CPRIT Contract, pursuant to which CPRIT will provide us with the CPRIT Grant of $17.6 million subject to the terms of the CPRIT Contract, to fund approximately two-thirds of the continued development of REYOBIQ for the treatment of patients with LM. We recognized $3.8 million, $5.8 million, $4.9 million and $0.2 million of grant revenue during the nine months ended September 30, 2025, years ended December 31, 2024, 2023 and 2022, respectively, all of which has been received. The amounts recognized represents CPRIT’s share of the costs incurred for our REYOBIQ development for the treatment of patients with LM. As of September 30, 2025, we had $1.1 million of deferred grant liability related to the CPRIT Grant.

Nasdaq Listing Compliance

On March 8, 2024, we received notice from the Listing Qualifications staff of Nasdaq (the “Staff”), notifying us that we no longer complied with the requirement under Nasdaq Listing Rule 5550(b)(1) to maintain a minimum of $2.5 million in stockholders’ equity (the “Minimum Stockholders’ Equity Requirement”) for continued listing on The Nasdaq Capital Market or the alternative requirements of having a market value of listed securities of $35 million or net income from continuing operations of $500,000 in the most recently completed fiscal year or two of the last three most recently completed fiscal years.

On September 5, 2024, Nasdaq notified us that we had not regained compliance with Nasdaq Listing Rule 5550(b)(1). We requested a hearing before the Nasdaq hearing panel and on October 30, 2024, we received a decision from the panel, notifying us that we had until March 4, 2025 to demonstrate compliance with the Minimum Stockholders’ Equity Requirement.

On March 7, 2025, we received notification from Nasdaq that it had regained compliance with the Minimum Stockholders’ Equity Requirement due to the March 2025 Private Placement.

Pursuant to Nasdaq Listing Rule 5815(d)(4)(B), we will be subject to a Mandatory Panel Monitor until March 7, 2026. If the Staff finds us again out of compliance with the Minimum Stockholders’ Equity Requirement before that date, we would not be permitted to provide the Staff with a plan of compliance with respect to that deficiency and the Staff would not be permitted to grant additional time for us to regain compliance with respect to that deficiency, nor would we be afforded an applicable cure or compliance period. Instead, the Staff would issue a “Delist Determination Letter” and we would have an opportunity to request a hearing before the panel regarding our continued listing.

Furthermore, on May 16, 2025, we received notice from Nasdaq that, because the closing bid price for our common stock has fallen below $1.00 per share for 30 consecutive business days, we no longer comply with the minimum bid price requirement pursuant to Nasdaq Listing Rule 5550(a)(2) (the “Minimum Bid Requirement”).

Nasdaq’s Minimum Bid Requirement notice has no immediate effect on the listing or trading of our common stock. Pursuant to Nasdaq Listing Rule 5810(c)(3)(A), we are provided an initial compliance period of 180 calendar days, or until November 12, 2025, to regain compliance with the Minimum Bid Requirement. To regain compliance, the closing bid price of our common stock must meet or exceed $1.00 per share for a minimum of 10 consecutive business days prior to November 12, 2025.

If we do not achieve compliance with the Minimum Bid Requirement by November 12, 2025, we may be eligible for an additional 180 calendar days to regain compliance. To qualify, we would be required to meet the continued listing requirement for market value of publicly held shares and all other Nasdaq initial listing standards, with the exception of the Minimum Bid Requirement, and provide written notice of its intention to cure the minimum bid price deficiency during the second compliance period by effecting a reverse stock split if necessary. If the Staff determines that we will not be able to cure the deficiency, or if we are otherwise not eligible for such additional compliance period, Nasdaq will provide notice that our common stock will be subject to delisting. In the event we receive notice that its common stock is being delisted, Nasdaq rules permit us to appeal any delisting determination by the Staff.

We intend to monitor the closing bid price of our common stock and may, if appropriate, consider implementing available options to regain compliance with the Minimum Bid Requirement.

On May 2, 2025, our stockholders granted discretionary authority to our board of directors to (i) amend our Certificate of Incorporation to combine outstanding shares of our common stock into a lesser number of outstanding shares, or a “reverse stock split,” at a specific ratio within a range of one-for twenty five (1-for-25) to a maximum of one-for-two hundred fifty (1-for-250), with the exact ratio to be determined by the board of directors in its sole discretion; and (ii) effect the reverse stock split, if at all, within twelve (12) months of the date the proposal is approved by stockholders.

In addition, on August 7, 2025, the stockholders granted discretionary authority to the Company’s board of directors to (i) amend the Company’s Certificate of Incorporation to combine outstanding shares of the Company’s common stock into a lesser number of outstanding shares, or a “reverse stock split,” at a specific ratio within a range of one-for two (1-for-2) to a maximum of one-for-two

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hundred fifty (1-for-250), with the exact ratio to be determined by the board of directors in its sole discretion; and (ii) effect the reverse stock split, if at all, within twelve (12) months of the date the proposal is approved by stockholders.

On June 3, 2025, the Staff notified the Company that it was not in compliance with the Minimum Stockholders’ Equity Requirement (the “June 3 Letter”). The Company reported stockholders’ equity (deficit) of ($23,641,000) in its Quarterly Report on Form 10-Q for the period ended March 31, 2025, and, as a result, did not satisfy the Minimum Stockholders’ Equity Requirement pursuant to Listing Rule 5550(b)(1). As a result, the Staff determined to delist the Company’s securities from Nasdaq, unless the Company timely requests an appeal of the Staff’s determination to a Hearings Panel (the “Panel”), pursuant to the procedures set forth in the Nasdaq Listing Rule 5800 Series. The Company timely requested a hearing, which hearing took place as scheduled on July 15, 2025.

On July 22, 2025, the Panel issued a decision (the “July 2025 Decision”) granting the Company’s request for continued listing on Nasdaq, subject to the Company demonstrating compliance with (1) the Minimum Stockholders’ Equity Requirement pursuant to Listing Rule 5550 (b)(1) by August 14, 2025 by filing a timely public disclosure describing the transactions undertaken by the Company to achieve compliance and demonstrate long-term compliance of the Minimum Stockholders’ Equity Requirement, and by providing an indication of its equity following those transactions, with the option by including in the public filing a balance sheet not older than 60 days with pro forma adjustments for any significant transactions or events occurring on or before the report date; and (2) the Minimum Bid Requirement by September 8, 2025.

On August 22, 2025, the Company received a letter (the “August 2025 Letter”) from Nasdaq confirming its compliance with Nasdaq Listing Rule 5550(b). Specifically, the August 2025 Letter confirmed that the Company was in compliance with both (1) the Market Value of Listing Securities standard under 5550(b)(2), which requires certain companies to maintain a market value of listed securities of at least $35 million as well as compliance with (2) the alternative stockholders’ equity threshold under 5550(b)(1) or the Minimum Stockholders’ Equity Requirement. Accordingly, the Company satisfied two alternative criteria under Nasdaq Listing Rule 5550.

As a result of such compliance, Nasdaq permitted the Company the remainder of the previously announced grace period to regain compliance with the $1.00 bid price rule under Nasdaq Listing Rule 5550(a)(2), through November 12, 2025. Nasdaq previously required that the Company remedy the bid price deficiency by September 8, 2025, a deadline that no longer applies.

The August 2025 Letter also provided that, solely with respect to the Equity Standard, the Company remains subject to a one-year panel monitoring period, through August 22, 2026. If, within that one-year monitoring period, the Staff determines that the Company no longer satisfies the Equity Standard (and the Company is not then in compliance with one of the alternative standards under Rule 5550(b)), the Company will not be permitted to provide the Staff with a plan of compliance and the Staff is not permitted to grant additional time to regain compliance with the Equity Standard nor will the Company be afforded an applicable cure or compliance period. Instead, the Staff will issue a delist determination letter, and the Company will have an opportunity to request a new hearing before the Nasdaq Hearings Panel, which request would stay any further action by the Staff pending the ultimate outcome of the hearing.

There can be no assurance that the Company will be able to regain compliance with the Minimum Bid Requirement or maintain compliance with the Equity Standard.

Funding and Material Cash Requirements

To date, our operating losses have been funded primarily from outside sources of invested capital from issuance of shares of our common and preferred equity, warrants, proceeds from the now-repaid in full term loan with Oxford, the margin loan facility under a line of credit with Pershing and grant funding. However, we have had, and will continue to have, an ongoing need to raise additional cash from outside sources through a combination of equity offerings, debt financings and potential collaboration, license or development agreements to fund our future clinical development programs, commercialization of CNSide, and other operations in the next twelve months from the filing of this Quarterly Report. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures, or declaring dividends. There can be no assurance that we will be able to continue to raise additional capital in the future. Our inability to raise additional cash would have a material adverse impact on our operations, implementation of our strategy and ability to maintain compliance with applicable requirements, including Nasdaq listing rules.

Our present and future funding and cash requirements will depend on many factors, including, among other things:

•
the progress, timing and completion of our ongoing and planned clinical trials and nonclinical studies;
•
our ability to receive, and the timing of receipt of, future regulatory approvals for our product candidates and the costs related thereto;
•
the development and utility of the CNSide Test;
•
the scope, progress, results and costs of our ongoing and planned operations;
•
the costs associated with expanding our operations and building our sales and marketing capabilities;
•
our ability to establish strategic collaborations;
•
the cost and timing of preparing, filing and prosecuting patent applications, maintaining and enforcing our intellectual property rights and defending any intellectual property-related claims;

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•
the revenue, if any, received from commercial sales of our product candidates, if approved; and
•
potential new product candidates that we identify and attempt to develop.

The accompanying condensed consolidated financial statements have been prepared assuming that we will continue to operate as a going concern, which contemplates the realization of assets and settlement of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classifications of liabilities that may result from uncertainty related to our ability to continue as a going concern.

Cash (used in) provided by operating, investing, and financing activities for the nine months ended September 30, 2025 and 2024 is summarized as follows (in thousands):

|  | Nine Months Ended September 30, |
Net cash provided by (used in): |  | 2025 |  |  | 2024 |
Operating activities |  | $ | (14,518 | ) |  | $ | (9,343 | )
Investing activities |  |  | 223 |  |  |  | (4,175 | )
Financing activities |  |  | 27,508 |  |  |  | 6,187 |
Net change in cash and cash equivalents |  | $ | 13,213 |  |  | $ | (7,331 | )

Material Cash Obligations

Under the CPRIT Contract, we receive matching funds for approximately two-thirds of the development costs for the development of REYOBIQ for the treatment of patients with LM, subject to various funding conditions. The CPRIT Contract is effective for three years, unless otherwise terminated pursuant to the terms of the contract. CPRIT may require us to repay some or all of the disbursed CPRIT Grant proceeds (with interest not to exceed 5% annually) in the event of the early termination of the CPRIT Contract.

Other than as described above, we have no purchase commitments or long-term contractual obligations, except for lease obligations as of September 30, 2025. In addition, we have no off-balance sheet arrangements (as defined in the rules and regulations of the SEC) that have or are reasonably likely to have a current or future effect on our financial condition, changes in financial condition, revenues or expenses, results of operations, liquidity, capital expenditures or capital resources that is material to investors.

Operating activities

Net cash used in operating activities for the nine months ended September 30, 2025 of $14.5 million was primarily related to the net loss of $16.7 million and $4.7 million of changes to operating assets and liabilities, partially offset by $3.1 million of noncash financing expenses, $0.8 million of stock-based compensation expense, and $2.6 million of changes to the fair value of derivative instruments.

Net cash used in operating activities for the nine months ended September 30, 2024 of $9.3 million was primarily related to the net loss of $9.1 million and a $5.7 million change to the fair value of derivative instruments, partially offset by $3.5 million of noncash financing expenses and $0.8 million of changes to operating assets and liabilities.

Investing activities

Net cash provided by investing activities for the nine months ended September 30, 2025 of $0.2 million was primarily related to the redemption of short-term investments of $11.3 million which was partially offset by the purchase of short-term investments of $11.1 million.

Net cash used in investing activities for the nine months ended September 30, 2024 of $4.2 million was related to the purchase of Biocept assets of $0.5 million, short-term investments of $7.1 million and purchase of fixed assets of $0.1 million, partially offset by the redemption of short-term investments of $3.7 million.

Financing Activities

Net cash provided by financing activities for the nine months ended September 30, 2025 of $27.5 million was related to $19.6 million in proceeds from the sale of common stock under the Lincoln Park Purchase Agreement, $15.9 million of proceeds from sale of common stock, Pre-Funded Warrants and warrants in connection with the March 2025 Private Placement, and $3.7 million of net proceeds from the issuance of notes payable and warrants, partially offset by $3.3 million repayment on the Pershing Credit Facility, $3.7 million repayment of Notes payable, $2.3 million of costs paid to investors pursuant to the Letter Agreement, $0.2 million of costs related to the sale of common stock, and $2.3 million of financing costs related to the return and cancellation of Private Placement Shares and Pre-Funded Warrants.

Net cash provided by financing activities for the nine months ended September 30, 2024 of $6.2 million was related to net proceeds of $7.3 million from the exercise of Series B Warrants from the May 2024 Private Placement and the drawdown of $3.3 million from the Pershing Credit Facility, partially offset by the repurchase of treasury stock for approximately $0.4 million and repayment of the principle balance under the Oxford loan of $4.0 million.

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Critical Accounting Policies and Significant Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires us to make estimates and assumptions that affect the reported amounts of our assets, liabilities, revenues and expenses, and that affect our recognition and disclosure of contingent assets and liabilities.

While our estimates are based on assumptions we consider reasonable at the time they were made, our actual results may differ from our estimates, perhaps significantly. If results differ materially from our estimates, we will make adjustments to our consolidated financial statements prospectively as we become aware of the necessity for an adjustment.

We believe it is important for you to understand our most critical accounting policies. Our critical accounting policies and estimates are discussed in our Annual Report on Form 10-K for the fiscal year ended December 31, 2024 and there have been no material changes during the nine months ended September 30, 2025, other than what was disclosed in Note 2 of the accompanying condensed consolidated financial statements.

Item 3. Quantitative and Qualitat ive Disclosures about Market Risk

Not applicable.

Item 4. Controls and Procedures

Evaluation of Disclosure Controls and Procedures

We maintain “disclosure controls and procedures,” as such term is defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act of 1934, as amended (the “Exchange Act”), that are designed to ensure that information required to be disclosed in our reports that we file or furnish pursuant to the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to our management, including our Chief Executive Officer (our principal executive officer) and Chief Financial Officer (our principal financial officer and principal accounting officer), as appropriate, to allow for timely decisions regarding required disclosure. In designing and evaluating the disclosure controls and procedures, management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives, and management necessarily is required to apply its judgment in evaluating the cost-benefit relationship of possible controls and procedures.

As required by Rule 13a-15(b) under the Exchange Act we carried out an evaluation, under the supervision and with the participation of our management, including our Chief Executive Officer (our principal executive officer) and Chief Financial Officer (our principal financial officer and principal accounting officer), of the effectiveness of our disclosure controls and procedures, as such term is defined under Rule 13a-15(e) and 15d-15(e) promulgated under the Exchange Act as of the end of the period covered by this Quarterly Report. Based on the foregoing, our Chief Executive Officer (our principal executive officer) and Chief Financial Officer (our principal financial officer and principal accounting officer) concluded that our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act) were effective at the reasonable assurance level as of the end of the period covered by this Quarterly Report.

Changes in Internal Control over Financial Reporting

There have been no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) during the quarter ended September 30, 2025, that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

PART II. OTHE R INFORMATION

Item 1. Legal Proceedings

None.

Item 1A. Ris k Factors

There have been no material changes to the risk factors disclosed in Part I, Item 1A, “Risk Factors” of our Annual Report on Form 10-K for the year ended December 31, 2024, which are incorporated herein by this reference, other than as set forth below.

We could be delisted from Nasdaq for failure to comply with the Minimum Stockholders’ Equity Requirement, the Minimum Bid Requirement or other applicable continued listing requirements and standards of Nasdaq, which would seriously harm the liquidity of our stock and our ability to raise capital.

Our common stock is currently listed on The Nasdaq Capital Market. In order to maintain that listing, we must maintain compliance with Nasdaq's continued listing requirements and standards. The Company timely requested a hearing, which hearing took place as scheduled on July 15, 2025. On July 22, 2025, the Panel issued the July 2025 Decision granting the Company’s request for continued listing on Nasdaq, subject to the Company demonstrating compliance with (1) the Minimum Stockholders’ Equity Requirement pursuant to Listing Rule 5550 (b)(1) by August 14, 2025 by filing a timely public disclosure describing the transactions undertaken by the Company to achieve compliance and demonstrate long-term compliance of the Minimum Stockholders’ Equity Requirement, and by

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providing an indication of its equity following those transactions, with the option by including in the public filing a balance sheet not older than 60 days with pro forma adjustments for any significant transactions or events occurring on or before the report date; and (2) the Minimum Bid Requirement by September 8, 2025. On August 22, 2025, the Company received the August 2025 Letter from Nasdaq confirming its compliance with Nasdaq Listing Rule 5550(b). Specifically, the August 2025 Letter confirmed that the Company was in compliance with both (1) the Market Value of Listing Securities standard under 5550(b)(2), which requires certain companies to maintain a market value of listed securities of at least $35 million as well as compliance with (2) the alternative stockholders’ equity threshold under 5550(b)(1) or the Minimum Stockholders’ Equity Requirement. Accordingly, the Company satisfied two alternative criteria under Nasdaq Listing Rule 5550. As a result of such compliance, Nasdaq permitted the Company the remainder of the previously announced grace period to regain compliance with the $1.00 bid price rule under Nasdaq Listing Rule 5550(a)(2), through November 12, 2025. Nasdaq previously required that the Company remedy the bid price deficiency by September 8, 2025, a deadline that no longer applies. The August 2025 Letter also provided that, solely with respect to the Equity Standard, the Company remains subject to a one-year panel monitoring period, through August 22, 2026. If, within that one-year monitoring period, the Staff determines that the Company no longer satisfies the Equity Standard (and the Company is not then in compliance with one of the alternative standards under Rule 5550(b)), the Company will not be permitted to provide the Staff with a plan of compliance and the Staff is not permitted to grant additional time to regain compliance with the Equity Standard nor will the Company be afforded an applicable cure or compliance period. Instead, the Staff will issue a delist determination letter, and the Company will have an opportunity to request a new hearing before the Nasdaq Hearings Panel, which request would stay any further action by the Staff pending the ultimate outcome of the hearing.

There can be no assurances that we will be able to comply with the applicable listing requirements and standards of Nasdaq.

Minimum Stockholders’ Equity Requirement

In March 2024, we received notice from the Listing Qualifications staff of Nasdaq (the “Staff”), notifying us that we no longer maintained at least $2.5 million in stockholders’ equity, as required under Nasdaq Listing Rule 5550(b)(1) (the “Minimum Stockholders’ Equity Requirement”).

On September 5, 2024, Nasdaq notified us that we had not regained compliance with the Minimum Stockholders’ Equity Requirement and that, as a result, unless we timely requested an appeal of this determination to a Nasdaq hearing panel, Nasdaq would move to suspend trading of our common stock and to have our shares of common stock delisted from The Nasdaq Capital Market. The Company timely requested a hearing before the panel, and the hearing was held on October 22, 2024. On October 30, 2024, Nasdaq provided us until March 4, 2025, to notify Nasdaq that we were in compliance with the Minimum Stockholders’ Equity Requirement. On March 7, 2025, the Company received notification from Nasdaq that it had regained compliance with the Minimum Stockholders’ Equity Requirement.

Pursuant to Nasdaq Listing Rule 5815(d)(4)(B), we will be subject to a Mandatory Panel Monitor until March 7, 2026. If the Staff finds we are again out of compliance with the Minimum Stockholders’ Equity Requirement before that date, we will not be permitted to provide the Staff with a plan of compliance with respect to that deficiency and the Staff would not be permitted to grant additional time for us to regain compliance with respect to that deficiency, nor would we be afforded an applicable cure or compliance period. Instead, the Staff would issue a “Delist Determination Letter” and we would have an opportunity to request a Nasdaq hearing panel regarding our continued listing.

On June 3, 2025, the Staff notified the Company that it was not in compliance with the Minimum Stockholders’ Equity Requirement. The Company reported stockholders’ equity (deficit) of ($23,641,000) in its Quarterly Report on Form 10-Q for the period ended March 31, 2025, and, as a result, did not satisfy the Minimum Stockholders’ Equity Requirement pursuant to Listing Rule 5550(b)(1). As a result, the Staff determined to delist the Company’s securities from Nasdaq, unless the Company timely requests an appeal of the Staff’s determination to a hearings panel, pursuant to the procedures set forth in the Nasdaq Listing Rule 5800 Series. The Company timely requested a hearing, which hearing took place as scheduled on July 15, 2025.

On July 22, 2025, the Panel issued the July 2025 Decision, granting the Company’s request for continued listing on Nasdaq, subject to the Company demonstrating compliance with (1) the Minimum Stockholders’ Equity Requirement pursuant to Listing Rule 5550 (b)(1) by August 14, 2025 by filing a timely public disclosure describing the transactions undertaken by the Company to achieve compliance and demonstrate long-term compliance of the Minimum Stockholders’ Equity Requirement, and by providing an indication of its equity following those transactions, with the option by including in the public filing a balance sheet not older than 60 days with pro forma adjustments for any significant transactions or events occurring on or before the report date; and (2) the Minimum Bid Requirement by September 8, 2025.

On August 22, 2025, the Company received a letter (the “August 2025 Letter”) from Nasdaq confirming its compliance with Nasdaq Listing Rule 5550(b). Specifically, the August 2025 Letter confirmed that the Company was in compliance with both (1) the Market Value of Listing Securities standard under 5550(b)(2), which requires certain companies to maintain a market value of listed securities of at least $35 million as well as compliance with (2) the alternative stockholders’ equity threshold under 5550(b)(1) or the Minimum Stockholders’ Equity Requirement. Accordingly, the Company satisfied two alternative criteria under Nasdaq Listing Rule 5550.

As a result of such compliance, Nasdaq permitted the Company the remainder of the previously announced grace period to regain compliance with the $1.00 bid price rule under Nasdaq Listing Rule 5550(a)(2), through November 12, 2025. Nasdaq previously required that the Company remedy the bid price deficiency by September 8, 2025, a deadline that no longer applies.

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The August 2025 Letter also provided that, solely with respect to the Equity Standard, the Company remains subject to a one-year panel monitoring period, through August 22, 2026. If, within that one-year monitoring period, the Staff determines that the Company no longer satisfies the Equity Standard (and the Company is not then in compliance with one of the alternative standards under Rule 5550(b)), the Company will not be permitted to provide the Staff with a plan of compliance and the Staff is not permitted to grant additional time to regain compliance with the Equity Standard nor will the Company be afforded an applicable cure or compliance period. Instead, the Staff will issue a delist determination letter, and the Company will have an opportunity to request a new hearing before the Nasdaq Hearings Panel, which request would stay any further action by the Staff pending the ultimate outcome of the hearing.

There can be no assurance that the Company will be able to regain compliance with the Minimum Bid Requirement or that the Company will maintain compliance with the Equity Standard.

Minimum Bid Requirement

On May 16, 2025, we received notice from Nasdaq that, because the closing bid price for the our common stock has fallen below $1.00 per share for 30 consecutive business days, we no longer comply with the minimum bid price requirement pursuant to Nasdaq Listing Rule 5550(a)(2) (the “Minimum Bid Requirement”). Nasdaq’s notice has no immediate effect on the listing or trading of our common stock. Pursuant to Nasdaq Listing Rule 5810(c)(3)(A), we are provided an initial compliance period of 180 calendar days, or until November 12, 2025, to regain compliance with the Minimum Bid Requirement. To regain compliance, the closing bid price of our common stock must meet or exceed $1.00 per share for a minimum of 10 consecutive business days prior to November 12, 2025.

If we do not achieve compliance with the Minimum Bid Requirement by November 12, 2025, we may be eligible for an additional 180 calendar days to regain compliance. To qualify, we would be required to meet the continued listing requirement for market value of publicly held shares and all other Nasdaq initial listing standards, with the exception of the Minimum Bid Requirement, and provide written notice of our intention to cure the minimum bid price deficiency during the second compliance period by effecting a reverse stock split if necessary. If the Staff determines that we will not be able to cure the deficiency, or if we are otherwise not eligible for such additional compliance period, Nasdaq will provide notice that our common stock will be subject to delisting. In the event we receive notice that our common stock is being delisted, Nasdaq rules permit us to appeal any delisting determination by the Staff. Furthermore, any efforts we take to meet the Minimum Bid Requirement, including pursuing a reverse stock split, may not be sufficient.

Potential Consequences of Delisting

There is no assurance that we will be able to meet Nasdaq’s listing requirements or comply with the requisite Nasdaq requirements to maintain our listing of common stock on Nasdaq. In the event that our common stock is delisted from Nasdaq, as a result of our failure to comply with the Minimum Stockholders’ Equity Requirement or the Minimum Bid Requirement or as a result of our failure to continue to comply with any other requirement for continued listing on Nasdaq, and we are not able to list our securities on Nasdaq or any other national securities exchange, we could face significant material adverse consequences, including:

•
a decline of the market price of our common stock;
•
a limited availability of market quotations for our common stock;
•
reduced liquidity for our common stock;
•
a determination that our common stock is a “penny stock,” which will require brokers trading in our common stock to adhere to more stringent rules and possibly result in a reduced level of trading activity in the secondary trading market for our securities;
•
a limited amount of news and analyst coverage for us;
•
a decreased ability to issue additional securities or obtain additional financing in the future; and
•
the incurring of additional costs under state blue sky laws in connection with any sales of our securities.

As of the date of this Quarterly Report, we require additional funding to develop our product candidates, conduct future operations, and repay our outstanding debt obligations. If we are unable to obtain the funds necessary to do so because our common stock is not listed on any national securities exchange, we may be required to delay, scale back or eliminate our product development activities, and we may be unable to continue our business operations.

If our common stock is delisted by Nasdaq, our common stock may be eligible to trade on an over-the-counter quotation system where an investor may find it more difficult to sell our stock or obtain accurate quotations as to the market value of our common stock. In the event our common stock is delisted from Nasdaq, we may not be able to list our common stock on another national securities exchange or obtain quotation on an over-the-counter quotation system.

Item 2. Unregistered Sal es of Equity Securities and Use of Proceeds

2(a): Unregistered Sales of Equity Securities and Use of Proceeds

Information required by Item 701 of Regulation S-K as to all unregistered sales of equity securities of the Company during the period covered by this Quarterly Report has previously been included in Current Reports on Form 8-K filed with the SEC.

2(b): Use of Proceeds from Registered Securities

None.

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2(c): Purchases of Equity Securities

The following table provides certain information with respect to the Company's purchases of its common stock for the three months ended September 30, 2025.

|  | Company Purchases of Common Stock |
Period |  | Total Number of Shares Purchased |  |  | Average Price Paid per Share |  |  | Total Number of Shares Purchased As Part of Publicly Announced Plans or Programs |  |  | Approximate Dollar Value of Shares That May Yet Be Purchased Under Plans or Programs(1) |
July 1 - 31, 2025 |  |  | - |  |  | $ | - |  |  |  | - |  |  | $ | - |
August 1 - 31, 2025 |  |  | 955,150 |  |  | $ | 0.66 |  |  |  | 955,150 |  |  | $ | - |
September 1 - 30, 2025 |  |  | 2,517,590 |  |  | $ | 0.66 |  |  |  | 2,517,590 |  |  | $ | - |
Total |  |  | 3,472,740 |  |  | $ | 0.66 |  |  |  | 3,472,740 |  |  | $ | - |

(1)
On March 4, 2025, the Company entered into a securities purchase agreement with various purchasers (the “Purchasers”), pursuant to which the Company issued to such Purchasers in a private placement (“March 2025 Private Placement”) common stock of the Company. On June 17, 2025, the Company and the Purchasers entered into a letter agreement (the “Letter Agreement”) with each of the Purchasers in an effort to, among other items, minimize the dilutive impact of the March 2025 Private Placement. The Letter Agreement provided for the return and cancellation of Private Placement Shares and Pre-Funded Warrants. Refer to Note 13. Stockholders’ Equity in Part I, Item 1 of this Quarterly Report on Form 10-Q for more information on the Letter Agreement.

Item 5. Other Information

On October 28, 2025, the Company entered into an amendment to the Letter Agreement and the Support Letters with certain March 2025 Private Placement Purchasers (the “Amendment Agreement”), pursuant to which (a) the Support Letters were terminated other than with respect to the participation rights granted therein, and (b) the repayment mechanism under the Letter Agreement was modified. As modified, the Company is no longer required to use 90% of the proceeds from any subsequent financing to repay the March 2025 Private Placement Purchasers. Instead, the Company is only required to retain sufficient funds in an interest bearing account to cover such repayment obligations and make such repayments upon request by any March 2025 Private Placement Purchaser who executed the Amendment Agreement until each such purchaser has received cash either from the Company or from reselling securities acquired in the March 2025 Private Placement in an amount equal to 115% of the purchase price such purchaser paid in the March 2025 Private Placement. If such requests are made, the requesting purchaser must return shares acquired in the March 2025 Private Placement at a value of $0.66 per share. The foregoing summary does not purport to be complete and is qualified in its entirety by reference to the full text of the Amendment Agreement, which is filed as Exhibit 10.3 to this Quarterly Report on Form 10-Q.

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Item 6. Exhibits

EXHIBIT INDEX

PLUS THERAPEUTICS, INC.

Exhibit Number | Exhibit Title | Filed with this Form 10-Q | Incorporated by Reference
Form | File No. | Date Filed
3.1 | Composite Certificate of Incorporation |  | 10-K | 001-34375 Exhibit 3.1 | 03/11/2016
3.2 | Certificate of Amendment to Amended and Restated Certificate |  | 8-K | 001-34375 Exhibit 3.1 | 05/10/2016
3.3 | Certificate of Amendment to Amended and Restated Certificate |  | 8-K | 001-34375 Exhibit 3.1 | 05/23/2018
3.4 | Certificate of Amendment to Amended and Restated Certificate |  | 8-K | 001-34375 Exhibit 3.1 | 07/29/2019
3.5 | Certificate of Amendment to Amended and Restated Certificate |  | 8-K | 001-34375 Exhibit 3.1 | 08/06/2019
3.6 | Certificate of Amendment to Amended and Restated Certificate |  | 8-K | 001-34375 Exhibit 3.1 | 04/28/2023
3.7 | Certificate of Amendment to the Certificate of Incorporation, as amended |  | 8-K | 001-34375 Exhibit 3.1 | 05/02/2025
3.8 | Amended and Restated Bylaws of Plus Therapeutics, Inc. |  | 8-K | 001-34375 Exhibit 3.1 | 09/21/2021
3.9 | Certificate of Designation of Preferences, Rights and Limitations of Series B Convertible Preferred Stock |  | 8-K | 001-34375 Exhibit 3.1 | 11/28/2017
3.10 | Certificate of Designation of Preferences, Rights and Limitations of Series C Convertible Preferred Stock |  | 8-K | 001-34375 Exhibit 3.1 | 07/25/2018
4.1 | Description of Securities |  | 10-K | 001-34375 Exhibit 4.1 | 03/30/2020
4.2 | Form of Common Stock Certificate |  | 10-K | 001-34375 Exhibit 4.33 | 03/09/2018
4.3 | Form of Pre-Funded Warrant |  | 8-K | 001-34375 Exhibit 4.1 | 05/09/2024
4.4 | Form of Amendment and Restatement of the May 2024 Series A Warrant |  | 10-Q | 011-34375 Exhibit 4.7 | 08/14/2024
4.5 | Form of Amendment and Restatement of the May 2024 Series B Warrant |  | 10-Q | 011-34375 Exhibit 4.8 | 08/14/2024
4.6 | Form of Pre-Funded Warrant |  | 8-K | 011-34375 Exhibit 4.1 | 02/18/2025
4.7 | Form of Warrant issued pursuant to the Securities Purchase and Exchange Agreement, dated February 13, 2025, by and among Plus Therapeutics, Inc. and the purchasers named therein |  | 8-K | 001-34375 Exhibit 4.2 | 02/18/2025
4.8 | Form of Pre-Funded Warrant |  | 8-K | 001-34375 Exhibit 4.1 | 03/04/2025
4.9 | Form of Amended March 2025 Series B Warrant |  | 8-K | 001-34375 Exhibit 4.1 | 06/17/2025

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10.1 | Form of Support Letter, dated July 11, 2025, by and between Plus Therapeutics, Inc. and certain holders |  | S-1 | 333-289526 Exhibit 10.41 | 08/12/2025
10.2 | Amended & Restated 2020 Stock Incentive Plan, amended August 7, 2025 | X |  |  |
10.3 | Form of Amendment Agreement, dated October 28, 2025 | X |  |  |
31.1* | Certification of Principal Executive Officer Pursuant to Securities Exchange Act Rule 13a-1.04(a), as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 | X |  |  |
31.2* | Certification of Principal Financial and Accounting Officer Pursuant to Securities Exchange Act Rule 13a-14(a), as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 | X |  |  |
32.1* | Certifications Pursuant to 18 U.S.C. Section 1350/ Securities Exchange Act Rule 13a-14(b), as adopted pursuant to Section 906 of the Sarbanes - Oxley Act of 2002 | X |  |  |
101.INS | Inline XBRL Instance Document – the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document | X |  |  |
101.SCH | Inline XBRL Taxonomy Extension Schema With Embedded Linkbase Documents | X |  |  |
104 | Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101) | X |  |  |

* In accordance with Item 601(b)(32)(ii) of Regulation S‑K and SEC Release No. 34‑47986, the certifications furnished in Exhibits 31.1, 31.2 and 32.1 hereto are deemed to accompany this Form 10‑Q and will not be deemed “filed” for purposes of Section 18 of the Exchange Act or deemed to be incorporated by reference into any filing under the Exchange Act or the Securities Act of 1933 except to the extent that the Company specifically incorporates them by reference.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

|  | PLUS THERAPEUTICS, INC.
|  | By: |  | /s/ Marc H. Hedrick
Dated: October 30, 2025 |  |  |  | Marc H. Hedrick
|  |  |  | President & Chief Executive Officer (Duly Authorized Officer and Principal Executive Officer)
|  | By: |  | /s/ Andrew Sims
Dated: October 30, 2025 |  |  |  | Andrew Sims
|  |  |  | Chief Financial Officer (Duly Authorized Officer and Principal Financial Officer and Principal Accounting Officer)

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