Syndax Ends Axatilimab IPF Development After Trial Miss

The MAXPIRe trial did not meet its primary endpoint. On October 12, 2026, as Syndax released the topline, Nick Botwood put the finding into plain words.

“The MAXPIRe trial did not meet its primary endpoint, and we are disappointed by this outcome given the promising scientific rationale in IPF,” he said.

The primary endpoint had been the annualized rate of decline in forced vital capacity. Forced vital capacity measures the volume of air a person can forcibly exhale after a full inhalation. Idiopathic pulmonary fibrosis is a progressive illness of irreversible lung scarring; the scar tissue thickens and stiffens the tissue around the air sacs, and that exhaled volume falls year by year. A drug able to slow the annualized loss would change the disease’s trajectory. MAXPIRe had asked whether axatilimab could do it. The answer was no.

MAXPIRe was a Phase 2 trial lasting 26 weeks. Randomized, double-blind, and placebo-controlled, the multicenter study enrolled 145 patients at 62 sites in 14 countries under the identifier NCT06132256. Patients were assigned two to one. Two received axatilimab at 0.3 mg per kilogram every two weeks; one received matching placebo on the same schedule. Randomization was stratified by background antifibrotic therapy so that any effect of existing drugs would not skew the comparison. Forced vital capacity readings taken across the 26 weeks fed a linear mixed effects model, a statistical method that estimates a trend from repeated measures, and that model projected the annualized rate of decline out to 52 weeks. The projected rate was the trial’s primary endpoint.

Secondary endpoints followed time to disease progression, the annualized decline in percent-predicted forced vital capacity, quality-of-life measures, and the change in percent-predicted diffusion capacity for carbon monoxide, the lung’s ability to move gas from air into blood.

Syndax does not plan to pursue further development of axatilimab in idiopathic pulmonary fibrosis. The company said the MAXPIRe result does not affect other ongoing axatilimab trials. No treatment-related fatal adverse events occurred in either arm. Rates of treatment discontinuation were low in both. The safety profile was comparable to placebo, with no new safety signals observed. The most frequent treatment-emergent adverse events in the axatilimab arm were generally consistent with previous studies of the antibody.

“We sincerely thank the patients, caregivers, clinicians and study teams who participated,” Botwood said. Chronic graft-versus-host disease is a syndrome that can follow bone marrow or stem-cell transplantation, when white blood cells from the donor recognize the recipient as foreign and attack the host’s tissues. “Axatilimab was well tolerated, with a safety profile consistent with prior studies supporting its continued development and use in cGVHD. There are multiple trials underway in cGVHD where axatilimab has shown remarkable results and we look forward to readouts from these trials later this year and in early 2028.”

Axatilimab reached Syndax in 2016 through a license of exclusive worldwide rights from UCB. The molecule is a first-in-class monoclonal antibody that blocks the colony-stimulating factor-1 receptor, a surface protein that helps regulate certain immune cells. In September 2021 Syndax and Incyte entered an exclusive worldwide co-development and co-commercialization agreement covering the antibody in chronic graft-versus-host disease and any future indications. The Food and Drug Administration has approved the same antibody as Niktimvo (axatilimab-csfr) for adults and for children weighing at least 40 kilograms whose chronic graft-versus-host disease has already failed at least two prior lines of systemic therapy.

Idiopathic pulmonary fibrosis typically brings a dry cough and breathlessness that worsens with exertion. Antifibrotic medicines already on the market can slow the decline in lung function; they do not reverse the scarring. The idiopathic pulmonary fibrosis path for the antibody is now closed. What remained was the Niktimvo label and the rest of the same calendar day.

Bristol Myers Squibb announced ALOFT-IPF results on the same October 12. That Phase 3 trial enrolled roughly 1,255 adults and measured absolute change in forced vital capacity at week 52; it met the endpoint at the 60-milligram twice-daily dose of admilparant, while the 120-milligram arm slowed decline without reaching statistical significance. Two idiopathic pulmonary fibrosis programs reported. Only one cleared its primary measure.

SNDX shares fell sharply in after-hours and overnight trading. The stock closed Monday’s session at $16.55 and traded overnight down 16.07 percent to $13.89. Idiopathic pulmonary fibrosis had contributed nothing to the commercial ledger. In the second quarter of 2026 Syndax narrowed its net loss to $49.36 million, or $0.55 per share, from $71.85 million, or $0.83 per share, a year earlier. The dates still open belonged to the frontline combination studies already running in chronic graft-versus-host disease.

A Phase 2 trial pairs axatilimab with ruxolitinib in newly diagnosed disease and is registered as NCT06388564. A Phase 3 trial pairs the same antibody with corticosteroids in the same frontline setting and is registered as NCT06585774.

“We remain highly focused on further advancing revumenib and axatilimab to frontline in the ongoing clinical trials which will unlock significant value for patients and shareholders. And we are well positioned to deliver breakthroughs for patients and build long-term value, with a robust pipeline, multiple upcoming catalysts, and strong financial position,” Michael A. Metzger said. “We look forward to working with our partner Incyte as we continue to build Niktimvo into a blockbuster franchise in cGVHD.”