EX-32.1 4 rlyb-20260630xex321.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 Rallybio Corporation (the “Company”) on Form 10-Q for the period ending June 30, 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 § 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 result of operations of the Company.

Date: August 6, 2026 | By: | /s/ Stephen Uden
|  | Stephen Uden, M.D.
|  | Chief Executive Officer, President and Director
|  | (Principal Executive Officer)