Instil Bio Pulls Plug On Lead Drug Development

Instil Bio, Inc. (NASDAQ:TIL) stock is trading lower on Tuesday. Axion Bio Inc., a wholly-owned subsidiary of Instil, decided to discontinue clinical development of AXN-2510.

AXN-2510, Instil’s lead asset, is a PD-L1xVEGF bispecific antibody in development for multiple solid tumors.

Axion and ImmuneOnco Biopharmaceuticals have agreed to terminate the license and collaboration agreement for AXN-2510 and AXN-27M.

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All rights previously licensed to Axion, including global development and commercial rights outside Greater China, have reverted to ImmuneOnco, subject to a limited license to Axion to wind down its clinical development activities.

The company didn't offer any details about the rationale for this decision.

In August 2024, Instil Bio in-licensed ex-China development and commercial rights to ImmueOnco's IMM2510, as well as an anti-CTLA-4 antibody, IMM27M.

Under the agreement, ImmuneOnco was to receive an upfront payment and potential near-term payments of up to $50 million, as well as potentially additional development, regulatory, and commercial milestones exceeding $2 billion plus single-digit to low double-digit percentage royalties on global ex-China sales.

In July 2025, ImmuneOnco shared preliminary safety and efficacy data from the Phase 2 study of IMM2510/AXN-2510 in combination with chemotherapy for front-line patients with advanced non-small cell lung cancer (NSCLC) conducted in China.

Interim data showed partial responses in 80% of squamous NSCLC front-line patients and in 46% of non-squamous NSCLC front-line patients.

In October 2025, Axion Bio dosed the first patient in its U.S. Phase 1 trial of ‘2510 as monotherapy in patients with relapsed or refractory solid tumors.

TIL Price Action: Instil Bio shares were down 52.48% at $5.84 at the time of publication on Tuesday. The stock is trading at a new 52-week low, according to Benzinga Pro data.

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