Trial Placed on FDA Clinical Hold for Testicular Toxicity
Non-clinical toxicology study reveals worrying results
Stephanie Vine | | 1 min read | News

The FDA has placed a clinical hold on Vyne Therapeutics’ phase Ib study in moderate-to-severe plaque psoriasis after testicular toxicity in dogs was observed in a non-clinical toxicology study. The drug candidate, VYN202, is an oral BD2-selective BET inhibitor.
Screening, enrollment, and patient dosing has been suspended. No serious adverse events have been noted in any human study subjects so far.
“While we are disappointed by this unexpected development, the safety and well-being of patients in our studies is our top priority,” said David Domzalski, President and Chief Executive Officer of VYNE. “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.”
The trial was designed to evaluate the safety of VYN202, with secondary objectives to evaluate the pharmacokinetic profile and preliminary evidence of efficacy, including improvement from baseline in psoriasis area and severity index scores. Top-line data would have been anticipated by the end of 2025.
According to the company, the phase Ia trial showed “that VYN202 had a favorable safety profile and also demonstrated VYN202’s potential to inhibit the production of multiple inflammatory biomarkers related to Th17, TNF and Th1/myeloid dysregulated activity.”
The clinical hold does not apply to VYNE’s ongoing phase IIb trial of repibresib gel in nonsegmental vitiligo. Top-line results are expected mid-year.

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