Xilio Therapeutics, Inc.

In the normal course of business, we enter into agreements that contain contractual obligations, of which the most significant to date include an operating lease for our corporate headquarters and certain license agreements.

Lease Agreement

We lease building space for our corporate headquarters at 828 Winter Street in Waltham, Massachusetts under a non-cancellable operating lease that expires in March 2030. Our operating lease includes the option to extend the term for a period of five years at the then-market rental rate. As of December 31, 2025, the remaining required payments for our operating lease, not including the optional extension period, are approximately $8.2 million. For further information regarding our operating lease agreement, please see Note 7, Leases, to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K.

Other Contractual Obligations

We are party to certain agreements that require us to pay third parties upon achievement of certain development, regulatory or commercial milestones or upon the consummation of specified transactions. Amounts related to contingent payments are not considered contractual obligations as they are contingent on the successful achievement of certain development, regulatory and commercial milestones that may not be achieved or upon the consummation of specified transactions that may not occur. We have not included payments contingent upon the achievement of certain development, regulatory or commercial milestones on our consolidated balance sheets. For further information regarding certain of our license agreements and amounts that could become payable in the future under those agreements, please see Note 6, Collaboration and License Agreements, to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K.

In addition, we are party to certain agreements with contract research organizations for clinical trials and clinical supply manufacturing and with vendors for preclinical research studies and other services and products for operating purposes. Such contracts are generally cancellable by us for convenience with up to 90 days of notice. We may be subject to certain termination fees or wind-down costs upon termination of these agreements. The exact amount of such costs are generally not fixed or estimable.