The U.S. Food and Drug Administration (FDA) has verbally informed VYNE Therapeutics Inc. that it placed a clinical hold on its Phase 1b study evaluating VYN202 for the treatment of moderate-to-severe plaque psoriasis.

The clinical hold determination was made following a recent observation of testicular toxicity in dogs from a non-clinical toxicology study with VYN202.

VYNE has suspended all screening, enrollment and patient dosing in the Phase 1b trial of VYN202 and intends to work with the FDA to resolve the clinical hold as soon as possible. To date, there have been no serious adverse events observed in subjects that have been enrolled in the Phase 1b study.

Does Not Apply to Vitiligo Trial

The clinical hold does not apply to VYNE’s ongoing Phase 2b trial of repibresib gel in nonsegmental vitiligo. Repibresib is a distinct and unique compound from VYN202. Top-line results from the 24-week double-blind, vehicle-controlled portion of the Phase 2b trial are expected mid-year.

“While we are disappointed by this unexpected development, the safety and well-being of patients in our studies is our top priority,” says David Domzalski, President and Chief Executive Officer of VYNE, in a news release. “We intend to work closely with the FDA to address the clinical hold as expeditiously as possible, and we plan to provide additional updates pending continued engagement with FDA.”