Syndax ends axatilimab development in IPF after the Phase 2 MAXPIRe trial missed its primary endpoint of annualised FVC decline.
Written By: Charvi Kalal, PharmD
Reviewed By: Pharmacally Editorial Team
Syndax Pharmaceuticals announced on October 12, 2026, that its Phase 2 MAXPIRe trial of axatilimab in idiopathic pulmonary fibrosis (IPF) did not meet its primary endpoint of annualised decline in forced vital capacity (FVC). The company reported a safety and tolerability profile comparable to placebo, with no new safety signals, but said it does not plan further development of axatilimab in IPF. The decision does not affect its ongoing development programmes in other indications.
Trial Design and Primary Endpoint
MAXPIRe (NCT06132256) was a 26-week, randomised, double-blind, placebo-controlled, multicentre Phase 2 trial involving 145 patients across 62 sites in 14 countries. Participants were randomised in a 2:1 ratio to receive axatilimab 0.3 mg/kg or placebo every two weeks. Randomisation was stratified according to background antifibrotic therapy.
The primary endpoint was the annualised rate of FVC decline, expressed as a 52-week rate and estimated using FVC measurements collected over 26 weeks through a linear mixed-effects model. Secondary endpoints included time to disease progression, annualised decline in percent-predicted FVC, quality-of-life measures and changes in percent-predicted diffusing capacity for carbon monoxide.
FVC measures the volume of air a person can forcibly exhale after taking a deep breath. In IPF, a progressive decline in FVC is an important indicator of worsening lung function.
Efficacy Results Remain Limited by Data Disclosure
Syndax confirmed that MAXPIRe failed to meet its primary endpoint but did not disclose numerical efficacy results, including the between-group difference in annualised FVC decline, confidence intervals or p-values. The company also did not report the outcomes of the secondary endpoints in its topline announcement.
Consequently, the available information does not establish the magnitude or precision of any treatment effect, nor does it explain why the trial failed to meet its primary endpoint. The result establishes that axatilimab did not achieve the trial’s prespecified primary efficacy objective, but the undisclosed data prevent a more detailed assessment of its performance against placebo.
The decision to stop further development in IPF represents the immediate development consequence of the negative topline result.
Safety Findings Do Not Offset the Efficacy Outcome
According to Syndax, axatilimab’s safety profile was comparable to placebo, and no new safety signals were identified. Treatment-emergent adverse events leading to discontinuation were infrequent in both groups, while the most common adverse events in the axatilimab arm were generally consistent with findings from earlier studies. No treatment-related fatal adverse events occurred in either group.
These findings provide reassurance regarding the reported safety experience but do not establish clinical benefit in IPF. Without detailed adverse-event data and the numerical efficacy results, the overall benefit-risk profile in this indication cannot be fully assessed.
Axatilimab Development Continues in cGVHD
Axatilimab is a monoclonal antibody that blocks the colony-stimulating factor 1 receptor (CSF-1R). Marketed as Niktimvo, it is approved by the US Food and Drug Administration for chronic graft-versus-host disease (cGVHD) after failure of at least two prior lines of systemic therapy in adult and paediatric patients weighing at least 40 kg.
Syndax continues to develop axatilimab in cGVHD, including a Phase 2 trial in combination with ruxolitinib (NCT06388564) and a Phase 3 trial in combination with corticosteroids (NCT06585774). The company has indicated that topline results from the Phase 2 programme are expected in the fourth quarter of 2026, with results from the Phase 3 programme anticipated in early 2028.
The MAXPIRe outcome does not establish whether axatilimab will succeed or fail in cGVHD, where the treatment is being evaluated in a different disease setting. The ongoing trials will provide separate evidence regarding its potential role in frontline treatment.
Development Outlook
MAXPIRe adds a negative efficacy outcome to axatilimab’s development history, ending its advancement in IPF despite a reported safety profile comparable to placebo. The absence of numerical efficacy results limits interpretation of the treatment effect and the reasons for the endpoint failure.
For Syndax, attention now remains on axatilimab’s established cGVHD indication and its frontline clinical programmes, alongside the company’s broader oncology portfolio, including revumenib. The upcoming cGVHD readouts will be important in determining whether axatilimab can demonstrate additional clinical value in that setting.
Reference
Syndax Announces Topline Results from MAXPIRe Phase 2 Trial of Axatilimab in Idiopathic Pulmonary Fibrosis, Syndax Pharmaceuticals, October 12, 2026
MAXPIRe: Study to Evaluate Axatilimab in Participants with Idiopathic Pulmonary Fibrosis (IPF), ClinicalTrials.gov ID NCT06132256
About the Writer
Charvi Kalal (LinkedIn) is a Pharm.D intern and aspiring medical writer with hands-on experience in medical writing, clinical research, pharmacovigilance, and clinical pharmacy. She has experience in medical content writing through CliMed, along with exposure to ADR monitoring, prescription analysis, patient counselling, literature review, and research documentation. Her research focuses on ADR monitoring and reporting in breast cancer patients receiving targeted therapy. With certifications in GCP, biomedical research, scientific writing, and clinical research, she is passionate about transforming scientific evidence into accurate, engaging, and accessible healthcare content.