Arena Pharma's Atopic Dermatitis Drug Fails To Meet Primary Endpoint, Stock Down 20%

(RTTNews) - Shares of Arena Pharmaceuticals, Inc. (ARNA) plunged 20% in extended session Monday after it skin inflammation drug failed to meet primary endpoint in a mid-stage trial.

Arena Pharmaceuticals announced topline results from the Phase 2b ADVISE clinical trial evaluating etrasimod, a highly selective, once-daily, oral sphingosine 1-phosphate receptor modulator, for the treatment of moderate-to-severe atopic dermatitis.

The company said etrasimod did not meet the trial's primary endpoint of Eczema Area and Severity Index change from baseline at week 12.

In the primary analysis of the trial, nearly one-third of participants in the 2 mg etrasimod group achieved clear or almost clear skin, as defined by the validated Investigator Global Assessment, which is the FDA endpoint for Phase 3 registration. The vIGA improvement was statistically significant compared to placebo at 12 weeks. Across the Eczema Area and Severity Index, EASI-75 and peak change in pruritis, etrasimod 2 mg demonstrated early and statistically significant effect at week 4.

Atopic dermatitis usually develops in early childhood and is more common in people who have a family history of the condition. The main symptom is a rash that typically appears on the arms and behind the knees, but can also appear anywhere. Treatment includes avoiding soap and other irritants. Certain creams or ointments may also provide relief from the itching.

ARNA closed Monday's trading at $87.42, up $0.78 or 0.90%, on the Nasdaq. The stock, however, slipped $17.42 or 19.93%, in the after-hours trade.