Syndax Drops 15% After Axatilimab IPF Trial Fails Primary Goal

Syndax Pharmaceuticals shares fell 15% after-hours following the failure of its Phase 2 MAXPIRe trial for axatilimab in treating idiopathic pulmonary fibrosis (IPF), prompting the company to halt further development in that indication.

The trial missed its primary endpoint measuring the annualized rate of decline in forced vital capacity, leading Syndax Pharmaceuticals to abandon additional research for the drug in this specific respiratory disease.

"Feeling really quite confident in both the design and the outcome" of the trial, said Chief Medical Officer Botwood during Syndax's fourth quarter fiscal 2025 earnings call on February 26, 2026, where he previously described the study as having the "potential to provide proof-of-concept data for axatilimab in IPF," according to a PR Newswire release.

Clinical Trial Design and Safety Profile

The MAXPIRe study evaluated 145 patients across 62 sites in 14 countries. Participants were randomized in a 2:1 ratio to receive either axatilimab at a dose of 0.3 mg/kg or a placebo administered every two weeks over a 26-week period.

Despite failing to meet its primary efficacy target, axatilimab was reported to be well tolerated by participants. According to the Investing.com report, the drug's safety profile remained comparable to the placebo arm, with no new safety signals identified and low rates of treatment-emergent adverse events leading to discontinuation across both groups.

Core Indications and Ongoing Operations

The halt of the IPF program narrows the immediate clinical focus for axatilimab back to its approved commercial uses. The drug is currently FDA approved for treating chronic graft-versus-host disease (cGVHD) in adult and pediatric patients weighing at least 40 kg who have experienced failure after at least two prior lines of systemic therapy.

Idiopathic pulmonary fibrosis is a severe and progressive lung disease characterized by scarring of lung tissue, causing a gradual and irreversible decline in lung function. The abrupt termination of the MAXPIRe trial eliminates a potential label expansion for the drug into fibrosis indications, shifting investor attention back to Syndax's core hematology and oncology pipeline performance.