Syndax Stock Drops 15% After Axatilimab Trial Failure

Syndax Pharmaceuticals (NASDAQ: SNDX) shares plunged 15% in after-hours trading on Monday after the biotechnology company announced disappointing results from a Phase 2 clinical trial evaluating axatilimab as a treatment for idiopathic pulmonary fibrosis (IPF).

The company confirmed that its MAXPIRe trial failed to meet its primary endpoint, which measured the annualized rate of decline in forced vital capacity (FVC), a key indicator of lung function in patients with pulmonary fibrosis.

Following the unsuccessful trial, Syndax Pharmaceuticals said it would discontinue further development of axatilimab for IPF, marking a setback for the company's efforts to expand the drug's therapeutic applications.

The Phase 2 MAXPIRe study involved 145 patients recruited from 62 clinical sites across 14 countries. Participants were randomly assigned in a 2:1 ratio to receive either axatilimab at a dosage of 0.3 mg/kg or a placebo every two weeks for 26 weeks.

Although axatilimab failed to demonstrate the required clinical effectiveness, the treatment maintained a favorable safety profile. Syndax reported that the drug was generally well tolerated, with safety outcomes comparable to those observed in the placebo group.

No new safety concerns emerged during the study. Additionally, treatment-related adverse events resulting in discontinuation remained uncommon in both groups, while neither group recorded treatment-related fatalities.

Despite the disappointing IPF trial results, Syndax emphasized that the findings would not affect ongoing clinical studies investigating axatilimab for other medical conditions.

Axatilimab has already received approval from the U.S. Food and Drug Administration (FDA) for treating chronic graft-versus-host disease (cGVHD) in adults and pediatric patients weighing at least 40 kilograms who have previously failed at least two systemic therapies.

The company continues to evaluate axatilimab in several clinical trials targeting cGVHD, with additional study results anticipated later in 2026 and early 2028.

Syndax also reaffirmed its commitment to advancing its broader drug development pipeline, including revumenib and axatilimab in frontline treatment settings.

While the MAXPIRe trial failure limits axatilimab's potential in pulmonary fibrosis, Syndax remains focused on developing treatments for other indications. Investors will likely monitor upcoming clinical trial results as the company pursues additional opportunities for its pharmaceutical portfolio.