Arena's lead drug misses on PhII in AD, thwacking stock, but company soldiers on into Phase III

On Monday, the company announced a failure: Its lead drug, the S1P inhibitor etrasimod, missed the primary endpoint on a Phase II trial for atopic dermatitis, failing to reduce symptoms on a standard clinical scale better than placebo. Yet they will continue on with a Phase III, betting that aberrations at one trial site thwarted that endpoint and that they can repeat success on a metric the FDA uses to evaluate approval.