Xenon Pharmaceuticals' acne drug XEN801 fails in mid-stage trial

Xenon Pharmaceuticals announced Friday that a Phase II study of the experimental drug XEN801 for the treatment of moderate to severe facial acne failed to meet its primary endpoint. Shares in the company fell as much as 45 percent on the news.

Top-line results from the trial showed that the SCD1 inhibitor did not demonstrate a significant difference from vehicle placebo for the main goal of the percent change in total lesion count from baseline to week 12. Xenon added that XEN801 did not also demonstrate significance relative to key secondary efficacy endpoints.

CEO Simon Pimstone remarked "despite the good scientific and preclinical rationale to pursue SCD1 as a novel acne target, the...results do not support this hypothesis or the continued development of XEN801."