Subsequent Events	12 Months Ended
Dec. 31, 2024
Subsequent Events.
Subsequent Events	14. Subsequent Events Collaboration, License and Option Agreement and Issuance of Common Stock On February 10, 2025, Xilio Development entered into a collaboration, license and option agreement with AbbVie Group Holdings for up to four programs leveraging the Company’s proprietary tumor-activation technology and platform, consisting of (i) an exclusive option for (a) an initial program to discover, develop and commercialize masked T cell engager molecules for an agreed upon initial target and backup target, and (b) subject to the terms of the agreement, up to two additional programs to discover, develop, and commercialize masked T cell engager molecules for an initial target and backup target determined at the time of program initiation and (ii) an exclusive license for a program to develop and commercialize a masked antibody-based immunotherapy. Under the collaboration, license and option agreement, the Company received an upfront cash payment of $42.0 million in February 2025. In addition, the Company will be eligible to receive up to approximately $2.1 billion in additional contingent payments and tiered royalties ranging in the mid to high single digits on annual global net product sales. In connection with the execution of the collaboration, license and option agreement, on February 10, 2025, the Company entered into a stock purchase agreement with AbbVie Inc. pursuant to which the Company issued and sold 4,347,826 shares of its common stock to AbbVie Inc. in a private placement at a purchase price of $2.30 per share for an aggregate purchase price of $10.0 million.

Subsequent Events

12 Months Ended

Dec. 31, 2024

14. Subsequent Events

Collaboration, License and Option Agreement and Issuance of Common Stock

On February 10, 2025, Xilio Development entered into a collaboration, license and option agreement with AbbVie Group Holdings for up to four programs leveraging the Company’s proprietary tumor-activation technology and platform, consisting of (i) an exclusive option for (a) an initial program to discover, develop and commercialize masked T cell engager molecules for an agreed upon initial target and backup target, and (b) subject to the terms of the agreement, up to two additional programs to discover, develop, and commercialize masked T cell engager molecules for an initial target and backup target determined at the time of program initiation and (ii) an exclusive license for a program to develop and commercialize a masked antibody-based immunotherapy.

Under the collaboration, license and option agreement, the Company received an upfront cash payment of $42.0 million in February 2025. In addition, the Company will be eligible to receive up to approximately $2.1 billion in additional contingent payments and tiered royalties ranging in the mid to high single digits on annual global net product sales.

In connection with the execution of the collaboration, license and option agreement, on February 10, 2025, the Company entered into a stock purchase agreement with AbbVie Inc. pursuant to which the Company issued and sold 4,347,826 shares of its common stock to AbbVie Inc. in a private placement at a purchase price of $2.30 per share for an aggregate purchase price of $10.0 million.