EX-32.1 5 alxo-ex32_1.htm EX-32.1

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of ALX Oncology Holdings Inc. (the “Company”), on Form 10-Q for the period ended March 31, 2026, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to section 906 of the Sarbanes-Oxley Act of 2002, that:

(1)
The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and
(2)
The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: May 8, 2026 |  | By: | /s/ Jason Lettmann
|  |  | Jason Lettmann
|  |  | Chief Executive Officer and Director (Principal Executive Officer)