Exhibit 10.15

CERTAIN INFORMATION HAS BEEN EXCLUDED FROM THIS AGREEMENT (INDICATED BY “[***]”) BECAUSE SLATE MEDICINES, INC. HAS DETERMINED SUCH INFORMATION (I) IS NOT MATERIAL AND (II) WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED.

FIRST AMENDMENT TO LICENSE AGREEMENT

This First Amendment (this “First Amendment”) to that certain License Agreement dated as of February 16, 2026 (the “Agreement”) by and between DARTSBIO PHARMACEUTICALS LTD., a corporation organized and existing under the laws of People’s Republic of China and having a place of business at Third Floor, East Sanwei GMP Building 3, Cuihai Ave, Cuiheng New District Zongshan City, Guangdong Province, China (“Dartsbio”), and SLATE MEDICINES, INC., a corporation organized and existing under the laws of Delaware and having a place of business at c/o RA Capital Management, L.P., 200 Berkeley Street, 18th Floor, Boston, MA 02116 USA (“Slate Medicines”) is dated as of August 11, 2026 (the “First Amendment Effective Date”). Slate Medicines and Dartsbio are sometimes referred to herein individually as a “Party” and collectively as the “Parties.” Capitalized terms used and not otherwise defined herein shall have the respective meanings given to them in the Agreement.

RECITALS

WHEREAS, Slate Medicines and Dartsbio previously entered into the Agreement; and

WHEREAS, the parties now wish to amend the Agreement to, among other things, remove the Subject Change of Control Payment set forth in Section 8.1(c) of the Agreement.

NOW, THEREFORE, in consideration of the foregoing, the covenants and premises contained in the Agreement and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Parties hereby agree as follows:

1. Amendment of License Agreement.

1.1. Amendment to Section 8.1(c). Section 8.1(c) of the Agreement is hereby deleted and of no further force and effect. In connection therewith, the defined terms “Subject Change of Control,” “Subject Change of Control Payment,” and “Qualified Financing Closing” are deleted from the Agreement in their entirety.

1.2. Amendment to Schedule 2.4. Schedule 2.4 of the Agreement is hereby amended and restated in its entirety as set forth on Annex I to this First Amendment.

2. Miscellaneous.

2.1. Full Force and Effect. This First Amendment amends the terms of the Agreement and is deemed incorporated into the Agreement. The provisions of the Agreement, as amended by this First Amendment, remain in full force and effect.

2.2. Entire Agreement. The Agreement and this First Amendment constitute the entire agreement, both written and oral, between the parties with respect to the subject matter hereof, and any and all prior agreements with respect to the subject matter hereof, either written or oral, expressed or implied, are superseded hereby, merged and canceled, and are null and void and of no effect.

2.3. Counterparts. This First Amendment may be executed in one (1) or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

[SIGNATURE PAGE TO FOLLOW]

 

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IN WITNESS WHEREOF, the parties have caused this First Amendment to be executed by their duly authorized representatives as of the First Amendment Effective Date.

 

DARTSBIO PHARMACEUTICALS LTD.		SLATE MEDICINES, INC.
By: /s/ Chunhe (Clay) Wang		By: /s/ Gregory Oakes
Name: Chunhe (Clay) Wang		Name: Gregory Oakes
Title: Chief Executive Officer		Title: Chief Executive Officer

 

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Annex I

Initial Technology Transfer Plan

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