FDA Halts Vyne Therapeutics' Psoriasis Trial Due to Safety Concerns

On April 25, 2025, the U.S. Food and Drug Administration (FDA) issued a clinical hold on Vyne Therapeutics' Phase 1b trial evaluating VYN202, an investigational oral bromodomain and extra-terminal domain (BET) inhibitor being developed for moderate to severe plaque psoriasis25. This regulatory action was prompted by the discovery of testicular toxicity in dogs during a non-clinical toxicology study of the drug1.

Key Facts

• The FDA verbally informed Vyne Therapeutics about the clinical hold decision after testicular toxicity was observed in canines during toxicology studies5
• Vyne has suspended all patient screening, enrollment, and dosing in the Phase 1b trial as a precautionary measure25
• No serious adverse events have been reported in human subjects participating in the study to date25
• The clinical hold comes approximately two months after Vyne announced the launch of this Phase 1b study2
• This hold does not affect Vyne's separate ongoing Phase 2b trial of repibresib gel for nonsegmental vitiligo, as repibresib is a distinct compound from VYN2025
• Top-line results from the vitiligo trial are still expected by mid-year 20255

David Domzalski, president and CEO of Vyne Therapeutics, expressed disappointment about this unexpected development but emphasized that patient safety remains their top priority2. The company plans to work closely with the FDA to address the clinical hold as quickly as possible and will provide additional updates after further engagement with the regulatory agency25.

Sources:

1. https://www.fiercebiotech.com/biotech/fda-puts-vyne-twist-slapping-hold-psoriasis-trial-over-testicular-toxicity

2. https://www.dermatologytimes.com/view/fda-places-clinical-hold-on-vyne-s-vyn202-phase-1b-trial-for-plaque-psoriasis

5. https://www.globenewswire.com/news-release/2025/04/25/3068263/0/en/VYNE-Therapeutics-Provides-Update-on-VYN202-Program.html