Eli Lilly Acquires Ajax Therapeutics for $2.3 Billion to Advance Novel JAK2 Inhibitor for Blood Cancers
Key Insights
Eli Lilly announced the acquisition of Ajax Therapeutics (search) for up to $2.3 billion to gain access to AJ1-11095, a first-in-class Type II JAK2 inhibitor currently in Phase 1 development.
AJ1-11095 represents a novel approach to treating myelofibrosis (search) and polycythemia vera (search) by targeting a different JAK2 (search) binding site than all currently approved therapies, potentially offering deeper and more durable disease control.
The investigational drug is designed to address treatment resistance issues with existing Type I JAK2 (search) inhibitors, with proof-of-concept clinical data expected to be presented in late 2026.
Eli Lilly and Company announced a definitive agreement to acquire Ajax Therapeutics (search) for up to $2.3 billion in cash, gaining access to a potentially transformative treatment for patients with myeloproliferative neoplasms (search) (MPNs). The acquisition centers on Ajax's lead asset, AJ1-11095, a first-in-class Type II JAK2 inhibitor that offers a novel mechanism of action for treating myelofibrosis (search) and polycythemia vera (search).
Novel Mechanism Addresses Treatment Limitations
AJ1-11095 represents a significant departure from existing therapies in the MPN treatment landscape. All currently approved JAK2 (search) inhibitors for patients with MPNs bind to the Type I conformation of JAK2. While these inhibitors provide clinical and symptomatic relief, many patients discontinue Type I JAK2 treatment due to lack of durable benefit or loss of response over time.
Ajax designed AJ1-11095 as a selective Type II JAK2 inhibitor to address these limitations. Based on its unique mode of binding JAK2 (search), the investigational drug has the potential to deliver deeper and more durable disease control than approved therapies. The compound is also positioned to provide a novel treatment option for patients who become resistant to Type I JAK2 inhibitors.
Clinical Development Progress
AJ1-11095 is currently being evaluated in a Phase 1 clinical trial, AJX-101, in patients with myelofibrosis (search) who have previously been treated with a Type I JAK2 inhibitor. The Phase 1 trial began in late 2024, and dose selection for future clinical development is expected in 2026. First proof-of-concept clinical data will be presented later in 2026.
The once-daily oral formulation is designed with a tolerability profile that would allow patients to remain on therapy longer and be used across both first- and second-line treatment settings.
Strategic Rationale and Leadership Perspectives
Jacob Van Naarden, executive vice president and president of Lilly Oncology and head of corporate business development, emphasized Lilly's long-standing confidence in Ajax's approach. "As a founding strategic investor in Ajax, Lilly has long believed in the approach and is excited about the potential for AJ1-11095 to deliver deeper and more durable efficacy than available treatments," Van Naarden stated. He noted that the company looks forward to presenting clinical proof-of-concept data later in 2026 and rapidly advancing AJ1-11095 into registrational clinical trials.
Martin Vogelbaum, co-founder and chief executive officer of Ajax Therapeutics (search), highlighted the scientific foundation underlying the development program. "We started Ajax to build on the work of its five scientific founders, including Ross Levine, MD, chief scientific officer at Memorial Sloan Kettering Cancer Center and chair of Ajax's scientific advisory board, who sought to develop a novel class of selective and more potent JAK2 (search) inhibitors to address the significant unmet need of patients with MPNs," Vogelbaum explained.
Transaction Details and Timeline
Under the terms of the agreement, Ajax shareholders could receive up to $2.3 billion in cash, inclusive of an upfront payment and subsequent payments upon achievement of certain clinical and regulatory milestones. The transaction is subject to customary closing conditions, including approval under the Hart-Scott-Rodino Antitrust Improvements Act of 1976.
The acquisition builds on Lilly's established capabilities in blood cancers (search) and represents a strategic expansion of the company's oncology portfolio. Ajax Therapeutics (search) developed its approach by combining deep cancer and structural biology insights from its founding scientists with advanced computational structure-based drug discovery platforms from its founding collaboration partner, Schrödinger, Inc.