Syndax Pharmaceuticals is ending development of axatilimab, sold as Niktimvo, in idiopathic pulmonary fibrosis. The randomized, double blind, placebo controlled Phase 2 MAXPIRe trial failed its primary endpoint, the annualized rate of decline in forced vital capacity over 26 weeks, and the company said it will not pursue the indication further. Shares fell about 17 percent in extended trading on October 12.
The 26 week study ran at 62 sites in 14 countries. Safety was not the problem: Syndax said the drug was well tolerated with a profile comparable to placebo, no new safety concerns, no treatment related deaths in either arm and few discontinuations for side effects. The drug simply did not slow lung function decline, which is a clean primary endpoint miss rather than a near miss rescued by secondary measures. The company disclosed no effect size in the topline reporting.
Niktimvo itself is not at risk. It is approved in the United States for chronic graft versus host disease after failure of at least two prior therapies, and Syndax and partner Incyte continue two studies in newly diagnosed chronic GVHD, a Phase 2 combination with ruxolitinib with topline data expected in the fourth quarter of 2026 and a pivotal Phase 3 combination with corticosteroids expected in early 2028. Syndax said the IPF result does not affect those programs.
The read for investors is about optionality. IPF was the credible route to a much larger market for a drug whose approved use is a transplant complication. With that route closed on a primary endpoint failure, the valuation case rests on GVHD line expansion and on Revuforj, the company’s other commercial product.