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Shares of Pliant Therapeutics PLRX have plunged 88.5% in the past three months following recent setbacks in the clinical development program of its lead product candidate, bexotegrast (PLN-74809), for treating idiopathic pulmonary fibrosis (IPF). Bexotegrast is an oral, small-molecule, dual selective inhibitor of αvß6 and αvß1 integrins.
IPF is the most prevalent and severe type of progressive pulmonary fibrosis, impacting around 150,000 patients in the United States and more than three million worldwide.
PLRX’s Recent Setbacks Concerning the IPF Study
In early February 2025, Pliant announced voluntarily pausing enrollment and dosing in the ongoing phase IIb BEACON-IPF study of bexotegrast in IPF patients, following a prespecified data review and recommendations by the study’s independent Data Safety Monitoring Board (DSMB).
Enrollment and dosing were temporarily put on hold as data was being reviewed to assess the DSMB's reasoning for its recommendation. The study remained blinded to uphold its integrity. However, Pliant has been unable to identify the rationale behind the DSMB's recommendation to pause enrollment and dosing in the BEACON-IPF study through a review of blinded data.
As a result, PLRX convened an external expert panel to review unblinded data from the ongoing phase IIb BEACON-IPF study of bexotegrast in IPF patients. Comprising world-renowned experts in pulmonary diseases and biostatistics, the panel was tasked to provide an independent recommendation to Pliant regarding the study.
In the past six months, shares of PLRX have plummeted 86.9% compared with the industry’s 9.9% decline.
Image Source: Zacks Investment Research
In March, following the subsequent secondary review by the external expert panel, Pilant announced its decision to discontinue the phase IIb BEACON-IPF study evaluating bexotegrast in IPF patients. An imbalance in unadjudicated IPF-related adverse events between the treatment and placebo groups drove the decision. However, early signs of efficacy were also observed on the forced vital capacity endpoint.
Management stated that BEACON-IPF is the first late-stage IPF study that was discontinued for safety reasons despite showing strong evidence of efficacy.
PLRX to Focus on Other Clinical Pipeline Candidates
Following the discontinuation of the mid-stage IPF study of its lead candidate, Pliant has shifted its focus to its two other clinical-stage pipeline candidates, which are being developed for oncology and neuromuscular indications.
PLRX is evaluating PLN-101095 as a monotherapy and in combination with Merck’s Keytruda (pembrolizumab) in a phase I dose-escalation study to treat patients with solid tumors that are resistant to immune checkpoint inhibitors. The company is currently dosing the fourth of five planned dose cohorts in the early-stage study. It recently reported interim data from the first three cohorts of the phase I study, where the combo therapy exhibited anti-tumor activity.