A phase 2 clinical trial has started recruiting participants to test the safety and efficacy of PLN-74809 at a dose of 320 mg per day for at least 6 months in patients with idiopathic pulmonary fibrosis (IPF). The moves comes after a positive review from an independent data safety monitoring board.

“We are pleased that the favorable safety and tolerability profile seen with PLN-74809 to date supports the advancement of our Phase 2a program to evaluate a higher dose at a longer treatment duration,” Bernard Coulie, MD, PhD, president and chief executive officer of Pliant Therapeutics, the developer of PLN-74809, said in a press release.

PLN-74809 is a small molecule, dual-selective inhibitor of αVβ1 and αVβ6, which normally activate transforming growth factor beta 1 (TGF-β1) in actively fibrotic tissues. Inhibiting these integrins should block the activation of TGF-β1 and thus prevent the growth of fibrotic tissues. 

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So far, PLN-74809 has been used in more than 450 people, including both healthy volunteers and patients, and it has not resulted in any drug-related serious or severe adverse events.

The phase 2a clinical trial is a randomized, double-blind, placebo-controlled study in an estimated 28 patients with IPF. The primary outcome measure is the safety and tolerability of PLN-74809. The secondary outcome measure is the pharmacokinetics of the treatment. Exploratory endpoints include changes in forced vital capacity (FVC), Quantitative Lung Fibrosis (QLF) score based on high-resolution computed tomography, and selected biomarkers over 6 months of treatment.

The trial is using the same sites and protocol as the phase 2a INTEGRIS-IPF clinical trial, for which recruitment was recently completed. INTEGRIS-IPF is testing PLN-74809 at daily doses of 40, 80, and 160 mg and will continue without modifications based on the recommendation of the independent data safety monitoring board. Topline data from that trial are expected in mid-2022.

PLN-74809 is also being tested for the treatment of primary sclerosing cholangitis.


Pliant Therapeutics announces positive DSMB safety review and commencement of enrollment of phase 2a trial of PLN-74809 at 320 mg dose in idiopathic pulmonary fibrosis. News release. Pliant Therapeutics, Inc.; February 24, 2022.