Alumis And Acelyrin Issue Breach Notice To Climb Bio Over Unpaid $3M Milestone Due January 1, 2026

On January 2, 2026, Alumis Inc. (the "Company") and its wholly-owned subsidiary Acelyrin, Inc. ("Acelyrin") issued a Notice of Material Breach and Notification of Claim for Indemnification to Climb Bio, Inc. ("Climb Bio"), after Climb Bio knowingly and willfully refused to pay a $3,000,000 Development Milestone payment due January 1, 2026 under the Asset Purchase Agreement, dated as of January 11, 2024, between Acelyrin, WH2, LLC and Tenet Medicines, Inc. (a wholly owned subsidiary of Climb Bio, Inc.) (the "APA"). 

 

Climb Bio has previously stated in its filings with the Securities and Exchange Commission ("SEC") that it is "obligated to (i) make total payments of up to $157.5 million to Acelyrin upon the achievement of various development, regulatory and commercial milestones, (ii) pay royalties in the single-digit percentages, subject to specified reductions, to Acelyrin on worldwide net sales in a given calendar year, and (iii) make non-refundable and non-creditable payments to Acelyrin on sublicense income with rates ranging from the low single digit to mid-teen percent depending on the stage of development of the most advanced licensed product incorporating or comprising budoprutug at the time of such sublicense." Despite these statements, Climb Bio has not timely paid a Development Milestone and on December 31, 2025 Climb Bio filed a declaratory judgment action in Delaware Superior Court asserting that its drug candidate, budoprutug, does not constitute a "Product" as defined in the APA. The Company notes that budoprutug was the program acquired under the APA and believes Climb Bio's position is contrary to the plain terms and intent of the APA and Climb Bio's own prior statements to Acelyrin.

 

The Company intends to pursue available rights and remedies against Climb Bio for material and willful breach of the APA, including without limitation by seeking the $3,000,000 Development Milestone payment, with interest, indemnification for the Company's attorneys' fees and costs (including those costs incurred by Climb Bio's default in its payment obligations and its filing of a declaratory judgment action), and other available relief. All capitalized terms used and not otherwise defined herein, have their respective meanings provided in the APA.