Vyne's BET inhibitor ends psoriasis trial after FDA hold

Vyne Therapeutics has scrapped its phase 1b psoriasis trial for VYN202 after an FDA hold, but will continue developing the drug for other immune-related diseases.

Backstory: The FDA halted the trial in April after a separate test in dogs revealed testicular toxicity. The hold was partially lifted for female patients at low doses, but Vyne opted not to pursue the higher 1 mg dose or male patients.

Why it matters: VYN202 showed promise in the trial before the hold: a 90% reduction in psoriasis severity at Week 8 among treated patients. The drug is designed to selectively inhibit the BD2 protein domain, avoiding the broader toxicity seen with pan-BD BET inhibitors.

Big picture: BET inhibitors show therapeutic promise, yet they face persistent safety challenges, particularly systemic toxicity. Vyne’s decision highlights the ongoing challenge of balancing efficacy with acceptable risk, a significant obstacle to the broader adoption of this drug class.

What’s next: The decision to shut down the trial entirely frees up resources for Vyne’s broader pipeline while preserving VYN202’s future in immune disorders. Vyne’s stock dropped 13% following the announcement.