Lilly to Acquire Ajax Therapeutics in deal worth up to $2.3bn

Eli Lilly has agreed to acquire Ajax Therapeutics for up to $2.3 billion, gaining AJ1-11095, a Phase 1 first-in-class Type II JAK2 inhibitor for myelofibrosis patients who have failed or become resistant to existing Type I JAK2 therapies.

Eli Lilly and Company has entered into a definitive agreement to acquire Ajax Therapeutics, Inc., a biopharmaceutical company focused on next-generation JAK inhibitors for myeloproliferative neoplasms (MPNs), according to official disclosures. Ajax’s lead asset, AJ1-11095, is an investigational once-daily oral Type II JAK2 inhibitor currently in a Phase 1 trial (AJX-101) for myelofibrosis patients previously treated with Type I JAK2 inhibitors the class of all currently approved JAK2 therapies for MPNs including myelofibrosis and polycythemia vera.

This development matters because many patients discontinue Type I JAK2 treatment due to lack of durable benefit or loss of response. AJ1-11095 was designed as a selective Type II inhibitor to potentially deliver deeper, more durable efficacy while offering a novel option for resistant patients.

The Phase 1 trial began in late 2024, with dose selection expected in 2026 and proof-of-concept data anticipated later that year. Lilly, a founding strategic investor in Ajax, plans to rapidly advance the asset into registrational trials. Industries impacted include oncology drug development, hematology, and targeted small-molecule therapeutics.

Stakeholders include MPN patients, hematologists, and investors in JAK-inhibitor competitors.

For investors, the deal’s structure up to $2.3 billion including milestone payments, reflects typical risk-sharing in early-stage oncology acquisitions. Closing is subject to HSR approval.

Eli Lilly is a global pharmaceutical company headquartered in Indianapolis, focused on oncology, diabetes, and neuroscience.

Ajax Therapeutics is a biopharmaceutical company based in New York, developing Type II JAK inhibitors for MPNs.