VYNE Therapeutics (VYNE) said Friday that the FDA has placed a clinical halt on its phase 1b trial of its psoriasis drug due to signs of testicular toxicity found in a recent animal study.

The company also said suspended new enrollment and patient treatment in the study and said it plans to cooperate closely with regulators to lift the hold.

VYNE noted that no serious side effects have been observed in human participants enrolled so far.

The FDA action does not impact VYNE's phase 2b trial of repibresib gel, which involves a separate drug candidate, the company said.

Shares of VYNE were down more than 30% in recent Friday premarket activity.

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