License and Option Agreements	12 Months Ended
Dec. 31, 2024
License and Option Agreements
License and Option Agreements	8.License and Option Agreements Xencor, Inc. 2020 Xencor Agreement In September 2020, the Company entered into a license agreement (the “2020 Xencor Agreement”) with Xencor, Inc. (“Xencor”), to obtain (i) an exclusive, royalty-bearing, sublicensable worldwide license under certain patent rights controlled by Xencor and (ii) a non-exclusive payment bearing license under certain know-how controlled by Xencor to research, develop, manufacture, market and sell three antibody product candidates, including ZB002. The 2020 Xencor Agreement became effective in November 2020, upon the Company’s issuance of 5,041,542 shares of its Series A Preferred Stock, which had a fair value of $16.1 million to Xencor as initial consideration. The Company concluded that as no processes or other activities that would constitute a business were acquired, and the acquired assets did not have an alternative future use, the upfront consideration was expensed to acquired IPR&D during the year ended December 31, 2020. The Company is required to pay Xencor tiered royalties on annual net sales of successfully commercialized products utilizing the licensed assets. The royalty percentage rates vary by geographic areas as defined in the 2020 Xencor Agreement and range from the mid-single digits to the mid-teens. The Company is also obligated to reimburse Xencor for third-party costs incurred by Xencor for certain patent filings, prosecution and maintenance as further specified in the 2020 Xencor Agreement. During the year ended December 31, 2024 no costs were incurred related to the 2020 Xencor Agreement. During the year ended December 31, 2023, the Company incurred immaterial costs related to the 2020 Xencor Agreement. 2021 Xencor Agreement In May 2021, the Company entered into a license agreement (the “2021 Xencor Agreement”) with Xencor to obtain an (i) exclusive, royalty-bearing, sublicensable worldwide license under certain patent rights controlled by Xencor and (ii) a non-exclusive payment bearing license under certain know-how controlled by Xencor to research, develop, manufacture, market and sell obexelimab. The 2021 Xencor Agreement became effective in November 2021, upon the execution of an amendment to the 2021 Xencor Agreement and the Company’s concurrent issuance of a warrant to Xencor (the “Xencor Warrant”) as initial consideration, which entitled Xencor to receive a number of the Company’s convertible preferred stock in the Company’s next “qualified financing”. The Company concluded that as no processes or other activities that would constitute a business were acquired, and the acquired assets did not have an alternative future use, the upfront consideration of $20.7 million was expensed to acquired IPR&D during the year ended December 31, 2021. The Company is obligated to make specified development, regulatory and commercial milestone payments of up to $10.0 million at Xencor’s option either in cash or fully-paid newly issued shares. The Company is obligated to make regulatory milestone payments up to $75.0 million. The Company is also obligated to make one-time sales milestone payments up to $385.0 million upon achieving milestone events of net sales in a given calendar year in the territory equal to certain threshold amounts. In addition, the Company is required to pay Xencor tiered royalties on annual net sales of successfully commercialized products utilizing obexelimab, with the royalty rates varying based on regions and ranging from the mid-single digits to the mid-teens. In April 2023, the Company incurred a $10.0 million development milestone pursuant to the 2021 Xencor Agreement, which Xencor elected to receive in the form of the Company’s Series B Preferred Stock. See Note 9, Convertible Preferred Stock, for details. The milestone was recorded as acquired IPR&D expense in the Company’s consolidated statements of operations and comprehensive loss. The Company did not record any expenses related to reimbursable patent-related costs during the year ended December 31, 2024. The Company recorded an immaterial amount to general and administrative expenses in the consolidated statements of operations and comprehensive loss during each of the year ended December 31, 2023, relating to reimbursable patent-related costs owed to Xencor. During the year ended December 31, 2024 no milestone expense was incurred. Dianthus Therapeutics Inc. In September 2020, the Company entered into an agreement (the “Dianthus Option Agreement”) with Dianthus Therapeutics Inc. (“Dianthus”), a therapeutic antibody company. Under the terms of the Dianthus Option Agreement, the Company obtained an exclusive option to negotiate and enter into exclusive license agreements with Dianthus for the rights to research, develop, manufacture, market and sell products related to either or both of two antibody product candidates based on Dianthus’ proprietary technology in China, Hong Kong, Macau and Taiwan (the “Zenas Territories”). Dianthus retains all rights to develop and commercialize the product candidate subjects of the two options outside of the Zenas Territories. Upon execution of the Dianthus Option Agreement, the Company issued 18,063 shares of its common stock to Dianthus as initial consideration, which was recorded to acquired IPR&D expense during the year ended December 31, 2020. Under the Dianthus Option Agreement, Dianthus will notify the Company when it has identified each of two antibody product candidates, and the Company will then have sixty (60) days to notify Dianthus if the Company intends to exercise each of the options. In September 2021, Dianthus notified the Company that it had identified the first lead antibody product candidate pursuant to the Dianthus Option Agreement, ZB005 (also known as DNTH103). In October 2021, the Company notified Dianthus of its intention to exercise its option to ZB005 pursuant to the Dianthus Option Agreement. This notification resulted in a $1.0 million milestone obligation to Dianthus, which was expensed in 2021 upon exercise and subsequently paid during the year ended December 31, 2022. The Company and Dianthus executed a license agreement for ZB005 in June 2022 (the “Dianthus License Agreement”). The Company is also required to reimburse Dianthus for a specified percentage of certain third-party costs which Dianthus incurs in its initial discovery and development activities related to each of the two options. To date, the Company has only exercised its option with respect to the ZB005 program, and as a result, it has only reimbursed Dianthus with respect to costs associated with the ZB005 program. During the years ended December 31, 2024 and 2023, the Company incurred $5.1 million and $3.0 million of reimbursable expenses, respectively, which are recorded within research and development expenses in the consolidated statements of operations and comprehensive loss. Of these amounts, $0.5 million and an immaterial amount were recorded in accounts payable, and $0.3 million and $0.4 million were recorded in accrued expenses on the Company’s consolidated balance sheets as of December 31, 2024 and 2023, respectively. The binding key terms included in the Dianthus License Agreement, and that would be included in a future license agreement if the Company exercises its option with respect to a second research program, also include the Company’s obligation to make specified development milestone payments to Dianthus, one time only, regardless of the number of assets the Company in-licenses from Dianthus with respect to such research program. The milestone obligations for each research program would total up to $11.0 million, based on achievement of each of the specified milestone events. If the Company successfully commercializes a product(s) under a license agreement, the Company will be obligated to make tiered royalty payments, on a product-by-product basis, to Dianthus on annual net sales of such products. Royalties will be calculated as specified percentages of annual net sales, ranging from the mid-single digits to the low-double digits, with each specified tiered level of annual net sales having a specified percentage. In October 2024, the Company entered into the Tenacia Agreement. Pursuant to the Tenacia Agreement, the Company transferred its rights, and obligations under the Dianthus Option Agreement and the Dianthus License Agreement to Tenacia. As a result, Zenas has no further obligations to Dianthus under the Dianthus Option Agreement and the Dianthus License Agreement. For additional information on our Tenacia Agreement, please see Note 7, License and Collaboration Revenue, to these consolidated financial statements. Viridian Therapeutics, Inc. In October 2020, the Company entered into a license agreement with Viridian Therapeutics, Inc. (“Viridian”), to obtain an exclusive, royalty-bearing, sublicensable license to research, develop, manufacture, market and sell certain antibody product candidates based on Viridian’s proprietary technology (the “Viridian Agreement”). The Company’s license rights are limited to non-oncology indications and to the Zenas Territories. Viridian retains its rights to develop and commercialize such product candidates outside of the Zenas Territories. Upon execution of the Viridian Agreement, the Company issued 38,707 shares of its common stock to Viridian as initial consideration which was recorded as acquired in-process research and development expense in its consolidated statements of operations and comprehensive loss for the year ended December 31, 2020. The Company is obligated to make development milestone payments to Viridian, totaling up to $12.0 million, based on achievement of each of the specified milestone events. The Company is also required to pay Viridian tiered royalties on annual net sales of successfully commercialized products utilizing the licensed technology. The royalty percentage rates range from the mid-single digits to the low-double digits. During the year ended December 31, 2024 and 2023, the Company did not incur or pay any milestones to Viridian. During the year ended December 31, 2021, the Company and Viridian entered into two letter agreements to authorize initiation of certain manufacturing and development activities related to the licensed product candidate, ZB001 (also known as VRDN-001). In each of the letter agreements the Company requested, and Viridian agreed, to engage a third-party contract manufacturer (the “CMO”) to initiate certain work with respect to activities pursuant to one or more statements of work under existing agreements between Viridian and the two CMOs. In May 2022, the Company entered into a manufacturing development and supply agreement with Viridian. The Company pays Viridian for all amounts the CMOs invoice to Viridian for the specified activities. The first letter agreement subsequently was amended three times to add further activities and costs to those detailed in the original letter agreement. During the years ended December 31, 2024 and 2023, the Company recognized an immaterial amount of expenses, respectively, which were recorded in research and development expenses in the consolidated statements of operations. As of December 31, 2024, and 2023, immaterial amounts were recorded in accounts payable and accrued expenses. Viridian has agreed to reimburse the Company for certain services it performs on Viridian’s behalf, with reimbursements being recorded as a reduction in research and development expenses. During the year ended December 31, 2024, the Company recorded $1.7 million in reimbursable expenses. During the year ended December 31, 2023, the Company had no reimbursable expenses. As of December 31, 2024, Viridian had not notified the Company of any additional antibody product candidate.

License and Option Agreements

12 Months Ended

Dec. 31, 2024

8.License and Option Agreements

Xencor, Inc.

2020 Xencor Agreement

In September 2020, the Company entered into a license agreement (the “2020 Xencor Agreement”) with Xencor, Inc. (“Xencor”), to obtain (i) an exclusive, royalty-bearing, sublicensable worldwide license under certain patent rights controlled by Xencor and (ii) a non-exclusive payment bearing license under certain know-how controlled by Xencor to research, develop, manufacture, market and sell three antibody product candidates, including ZB002. The 2020 Xencor Agreement became effective in November 2020, upon the Company’s issuance of 5,041,542 shares of its Series A Preferred Stock, which had a fair value of $16.1 million to Xencor as initial consideration. The Company concluded that as no processes or other activities that would constitute a business were acquired, and the acquired assets did not have an alternative future use, the upfront consideration was expensed to acquired IPR&D during the year ended December 31, 2020.

The Company is required to pay Xencor tiered royalties on annual net sales of successfully commercialized products utilizing the licensed assets. The royalty percentage rates vary by geographic areas as defined in the 2020 Xencor Agreement and range from the mid-single digits to the mid-teens.

The Company is also obligated to reimburse Xencor for third-party costs incurred by Xencor for certain patent filings, prosecution and maintenance as further specified in the 2020 Xencor Agreement. During the year ended December 31, 2024 no costs were incurred related to the 2020 Xencor Agreement. During the year ended December 31, 2023, the Company incurred immaterial costs related to the 2020 Xencor Agreement.

2021 Xencor Agreement

In May 2021, the Company entered into a license agreement (the “2021 Xencor Agreement”) with Xencor to obtain an (i) exclusive, royalty-bearing, sublicensable worldwide license under certain patent rights controlled by Xencor and (ii) a non-exclusive payment bearing license under certain know-how controlled by Xencor to research, develop, manufacture, market and sell obexelimab. The 2021 Xencor Agreement became effective in November 2021, upon the execution of an amendment to the 2021 Xencor Agreement and the Company’s concurrent issuance of a warrant to Xencor (the “Xencor Warrant”) as initial consideration, which entitled Xencor to receive a number of the Company’s convertible preferred stock in the Company’s next “qualified financing”. The Company concluded that as no processes or other activities that would constitute a business were acquired, and the acquired assets did not have an alternative future use, the upfront consideration of $20.7 million was expensed to acquired IPR&D during the year ended December 31, 2021.

The Company is obligated to make specified development, regulatory and commercial milestone payments of up to $10.0 million at Xencor’s option either in cash or fully-paid newly issued shares. The Company is obligated to make regulatory milestone payments up to $75.0 million. The Company is also obligated to make one-time sales milestone payments up to $385.0 million upon achieving milestone events of net sales in a given calendar year in the territory equal to certain threshold amounts. In addition, the Company is required to pay Xencor tiered royalties on annual net sales of successfully commercialized products utilizing obexelimab, with the royalty rates varying based on regions and ranging from the mid-single digits to the mid-teens.

In April 2023, the Company incurred a $10.0 million development milestone pursuant to the 2021 Xencor Agreement, which Xencor elected to receive in the form of the Company’s Series B Preferred Stock. See Note 9, Convertible Preferred Stock, for details. The milestone was recorded as acquired IPR&D expense in the Company’s consolidated statements of operations and comprehensive loss. The Company did not record any expenses related to reimbursable patent-related costs during the year ended December 31, 2024. The Company recorded an immaterial amount to general and administrative expenses in the consolidated statements of operations and comprehensive loss

during each of the year ended December 31, 2023, relating to reimbursable patent-related costs owed to Xencor. During the year ended December 31, 2024 no milestone expense was incurred.

Dianthus Therapeutics Inc.

In September 2020, the Company entered into an agreement (the “Dianthus Option Agreement”) with Dianthus Therapeutics Inc. (“Dianthus”), a therapeutic antibody company. Under the terms of the Dianthus Option Agreement, the Company obtained an exclusive option to negotiate and enter into exclusive license agreements with Dianthus for the rights to research, develop, manufacture, market and sell products related to either or both of two antibody product candidates based on Dianthus’ proprietary technology in China, Hong Kong, Macau and Taiwan (the “Zenas Territories”). Dianthus retains all rights to develop and commercialize the product candidate subjects of the two options outside of the Zenas Territories. Upon execution of the Dianthus Option Agreement, the Company issued 18,063 shares of its common stock to Dianthus as initial consideration, which was recorded to acquired IPR&D expense during the year ended December 31, 2020.

Under the Dianthus Option Agreement, Dianthus will notify the Company when it has identified each of two antibody product candidates, and the Company will then have sixty (60) days to notify Dianthus if the Company intends to exercise each of the options. In September 2021, Dianthus notified the Company that it had identified the first lead antibody product candidate pursuant to the Dianthus Option Agreement, ZB005 (also known as DNTH103). In October 2021, the Company notified Dianthus of its intention to exercise its option to ZB005 pursuant to the Dianthus Option Agreement. This notification resulted in a $1.0 million milestone obligation to Dianthus, which was expensed in 2021 upon exercise and subsequently paid during the year ended December 31, 2022. The Company and Dianthus executed a license agreement for ZB005 in June 2022 (the “Dianthus License Agreement”).

The Company is also required to reimburse Dianthus for a specified percentage of certain third-party costs which Dianthus incurs in its initial discovery and development activities related to each of the two options. To date, the Company has only exercised its option with respect to the ZB005 program, and as a result, it has only reimbursed Dianthus with respect to costs associated with the ZB005 program. During the years ended December 31, 2024 and 2023, the Company incurred $5.1 million and $3.0 million of reimbursable expenses, respectively, which are recorded within research and development expenses in the consolidated statements of operations and comprehensive loss. Of these amounts, $0.5 million and an immaterial amount were recorded in accounts payable, and $0.3 million and $0.4 million were recorded in accrued expenses on the Company’s consolidated balance sheets as of December 31, 2024 and 2023, respectively.

The binding key terms included in the Dianthus License Agreement, and that would be included in a future license agreement if the Company exercises its option with respect to a second research program, also include the Company’s obligation to make specified development milestone payments to Dianthus, one time only, regardless of the number of assets the Company in-licenses from Dianthus with respect to such research program. The milestone obligations for each research program would total up to $11.0 million, based on achievement of each of the specified milestone events. If the Company successfully commercializes a product(s) under a license agreement, the Company will be obligated to make tiered royalty payments, on a product-by-product basis, to Dianthus on annual net sales of such products. Royalties will be calculated as specified percentages of annual net sales, ranging from the mid-single digits to the low-double digits, with each specified tiered level of annual net sales having a specified percentage.

In October 2024, the Company entered into the Tenacia Agreement. Pursuant to the Tenacia Agreement, the Company transferred its rights, and obligations under the Dianthus Option Agreement and the Dianthus License Agreement to Tenacia. As a result, Zenas has no further obligations to Dianthus under the Dianthus Option Agreement and the Dianthus License Agreement.

For additional information on our Tenacia Agreement, please see Note 7, License and Collaboration Revenue, to these consolidated financial statements.

Viridian Therapeutics, Inc.

In October 2020, the Company entered into a license agreement with Viridian Therapeutics, Inc. (“Viridian”), to obtain an exclusive, royalty-bearing, sublicensable license to research, develop, manufacture, market and sell certain antibody product candidates based on Viridian’s proprietary technology (the “Viridian Agreement”). The Company’s license rights are limited to non-oncology indications and to the Zenas Territories. Viridian retains its rights to develop and commercialize such product candidates outside of the Zenas Territories. Upon execution of the Viridian Agreement, the Company issued 38,707 shares of its common stock to Viridian as initial consideration which was recorded as acquired in-process research and development expense in its consolidated statements of operations and comprehensive loss for the year ended December 31, 2020.

The Company is obligated to make development milestone payments to Viridian, totaling up to $12.0 million, based on achievement of each of the specified milestone events. The Company is also required to pay Viridian tiered royalties on annual net sales of successfully commercialized products utilizing the licensed technology. The royalty percentage rates range from the mid-single digits to the low-double digits. During the year ended December 31, 2024 and 2023, the Company did not incur or pay any milestones to Viridian.

During the year ended December 31, 2021, the Company and Viridian entered into two letter agreements to authorize initiation of certain manufacturing and development activities related to the licensed product candidate, ZB001 (also known as VRDN-001). In each of the letter agreements the Company requested, and Viridian agreed, to engage a third-party contract manufacturer (the “CMO”) to initiate certain work with respect to activities pursuant to one or more statements of work under existing agreements between Viridian and the two CMOs. In May 2022, the Company entered into a manufacturing development and supply agreement with Viridian. The Company pays Viridian for all amounts the CMOs invoice to Viridian for the specified activities. The first letter agreement subsequently was amended three times to add further activities and costs to those detailed in the original letter agreement.

During the years ended December 31, 2024 and 2023, the Company recognized an immaterial amount of expenses, respectively, which were recorded in research and development expenses in the consolidated statements of operations. As of December 31, 2024, and 2023, immaterial amounts were recorded in accounts payable and accrued expenses. Viridian has agreed to reimburse the Company for certain services it performs on Viridian’s behalf, with reimbursements being recorded as a reduction in research and development expenses. During the year ended December 31, 2024, the Company recorded $1.7 million in reimbursable expenses. During the year ended December 31, 2023, the Company had no reimbursable expenses. As of December 31, 2024, Viridian had not notified the Company of any additional antibody product candidate.