Pliant Therapeutics Halts Idiopathic Pulmonary Fibrosis Study, Stock Plummets

Pliant Therapeutics has suspended dosing and enrollment in its Phase IIb/III BEACON-IPF study for bexotegrast, a potential treatment for idiopathic pulmonary fibrosis (IPF). The decision, announced on Friday, follows a recommendation by an independent data safety monitoring board (DSMB) after a prespecified data review. The news sent Pliant's stock crashing by approximately 58% in aftermarket trading.

Bexotegrast: A Promising Candidate Faces Setback

Bexotegrast, an oral small-molecule dual-selective blocker of αvβ6 and αvβ1 integrins, had shown promise in earlier trials. These integrins play a crucial role in activating TGF-β, a profibrotic cytokine implicated in the progression of IPF. By inhibiting these integrins, bexotegrast aims to prevent the formation and growth of scar tissue in the lungs.

The drug candidate had previously received Fast Track and Orphan Drug designations from the FDA, highlighting its potential significance in addressing the unmet needs of IPF patients. In May 2024, Pliant reported encouraging topline Phase IIa data, demonstrating a notable reduction in lung collagen in treated patients, as measured by positron emission tomography scanning. The results also showed improvements in forced vital capacity and reduced cough severity compared to placebo.

Uncertain Future for BEACON-IPF Study

While the specific reasons for the DSMB's recommendation remain unclear, Pliant has stated that it is reviewing the BEACON-IPF data to understand the rationale behind the decision. The company has emphasized that patients already enrolled in the study will continue to participate, and the trial's blinding will be maintained to preserve its integrity.

The suspension of the BEACON-IPF study raises questions about the future of bexotegrast and Pliant's position in the competitive IPF treatment landscape. As the company works to analyze the data and determine next steps, the implications for both the drug's development timeline and Pliant's overall pipeline strategy remain uncertain.

Competitive Landscape in IPF Treatment

The setback for Pliant comes amid increasing activity in the IPF treatment space. In January, Eli Lilly entered into a $780 million licensing deal with Mediar Therapeutics for MTX-463, an anti-WISP1 antibody with first-in-class potential for IPF. The agreement, which includes $99 million upfront and up to $687 million in milestones, underscores the significant interest and investment in novel IPF therapies.

Additionally, in November 2024, Insilico Medicine reported positive results from a Phase IIa IPF study for its AI-developed asset ISM001-055. The trial demonstrated dose-dependent improvements in lung function, as measured by forced vital capacity.

As Pliant navigates the challenges presented by the BEACON-IPF study suspension, the competitive landscape continues to evolve, with multiple companies pursuing innovative approaches to address the significant unmet needs in IPF treatment.