Pliant Therapeutics has discontinued a phase 2b/3 trial after recording at least a 7% higher rate of adverse events tied to idiopathic pulmonary fibrosis (IPF) in the treatment arms compared to placebo.
The trial, dubbed BEACON-IPF, was assessing the biotech’s lead candidate, an oral small molecule called bexotegrast. The study had an estimated enrollment of 350 patients and a readout slated for mid-2026, according to ClinicalTrials.gov.
In February, after a prespecified review of the study’s data and at the recommendation of an independent safety committee, Pliant halted dosing and enrollment of the trial. At the time, the California-based biotech didn’t share further information about the voluntary pause.
Now, the company has said “an imbalance in unadjudicated IPF-related adverse events between the treatment and placebo groups” prompted the early trial termination, according to a March 3 release.
The decision to end the study was made at the recommendation of an outside expert panel after Pliant conducted a secondary review, according to the release.
The study was designed to include 52 weeks of treatment, but the mean exposure duration for patients was about 17 weeks before the study was stopped.
The percentage of IPF-related adverse events among two treatment groups—participants receiving bexotegrast were given doses of either 160-mg or 320-mg—was about 10%. That’s compared to a lower than 3% rate of IPF-related adverse events for patients in the placebo arm.
Specifics regarding the severity or type of adverse events were not shared.
Pliant will determine the next steps for bexotegrast, a dual selective inhibitor of αvß6 and αvß1 integrins, after analyzing the trial’s complete dataset. Depending on the full findings, the biotech said it may consider launching other phase 2b studies with lower doses in pulmonary fibrosis and possibly other indications, such as liver disease.
Despite the safety signals, the biotech said that early evidence of efficacy on the main endpoint—forced vital capacity—was observed.
Bexotegrast has has received fast track and orphan drug tags from the FDA in IPF and primary sclerosing cholangitis (PSC), and is Pliant’s most clinically advanced asset.
Since the discontinuation was announced this morning, Pliant’s stock has nearly halved, dropping 49% from $3.10 per share to $1.60 by 11 a.m. ET.