Exhibit 10.3

AMENDMENT No. 2 TO

MANAGEMENT SERVICES AGREEMENT

This Amendment dated as of March 25, 2026, (the “Amendment”), is by and between DiamiR Biosciences Corp. a Delaware, U.S., incorporated company (the “Service Provider”) and Aptorum Therapeutics Limited (“Aptorum Therapeutics,” a Cayman Islands exempted company with limited liability, Service Provider and Aptorum Therapeutics, each a “Party” and collectively, the “Parties”).

BACKGROUND

WHEREAS, the Parties entered into that certain Management Services Agreement dated July 14, 2025 (as amended on December 2, 2025, the “MSA”). Capitalized terms used but not otherwise defined herein shall have the meanings ascribed to them in the MSA.

WHEREAS, the Parties seek to extend the term of the MSA;

WHEREAS, this Amendment constitutes a written agreement signed by the necessary parties in order to effectuate the amendments to the MSA specified below.

NOW, THEREFORE, in consideration of the foregoing and the respective covenants and agreements set forth herein, the parties hereto agree as follows:

“The Agreement shall commence on the date hereof and shall continue until the earlier (i) the closing of the transaction(s) contemplated by the Definitive Agreements; or (ii) June 30, 2026.”

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