Material Agreement, Financial Obligation (Form 8-K)

On September 5, 2025, Cogent Biosciences, Inc. ("Cogent") and BP THIRD AVENUE LLC, an affiliate of Boston Properties (the "Landlord"), entered into a lease agreement (the "Lease") pursuant to which Cogent will lease approximately 31,518 square feet of office space in the building known as 180 CityPoint and having an address at 180 Third Avenue, 4^th Floor, Waltham, Massachusetts 02451 (the "Leased Space"). The new office will serve as Cogent's corporate headquarters and replace its existing headquarters in Waltham, which is subject to a sublease that expires in September 2026.

The Leased Space will be newly built out by the Landlord with a fit-for-purposedesign under a turnkey model, and Cogent is not anticipating any material tenant improvement costs associated with the buildout. The term of the Lease will commence when Landlord has substantially completed all construction and the Leased Space is ready for occupancy, which is expected to be in May 2026 (the "Commencement Date"). The Lease will have a term of seven (7) years and ten (10) months from the Commencement Date, and Cogent has an option to extend the term of the Lease for an additional five-year period. Cogent's obligation to pay base rent begins five (5) months after the Commencement Date at an initial rate of $32.00 per square foot. Rent will be payable in equal monthly installments and subject to annual increases of $1.00 per square foot over the term. Additionally, Cogent is required to pay its share of operating expenses and property taxes as additional rent. In connection with the Lease, Cogent will deposit with the Landlord a letter of credit in the amount of approximately $336,000 as a security deposit.

The foregoing description of the terms of the Lease does not purport to be a complete description of the rights and obligations of the parties thereunder and is qualified in its entirety by reference to the Lease, which is filed as Exhibit 10.1 herewith.

The information set forth in Item 1.01 above is incorporated herein by reference.