Sophiris Bio shares slide on Phase III results of PRX302

Biotech company Sophiris Bio (Nasdaq: SPHS) saw shares in the company fall up to almost 80% following an announcement of disappointing results for its PRX302.

Its interim analysis of a Phase III trial indicated that PRX302 would not meet a predefined efficacy threshold as a treatment for lower urinary tract symptoms of benign prostatic hyperplasia. Sophiris said the ongoing PLUS-1 study is unaffected by this, and that the trial will continue until the primary endpoint, the change in the International Prostate Symptom Score (IPSS) from baseline, is evaluated at 52 weeks.

The study was designed to assess safety and efficacy of a single PRX302 dose for the treatment of benign prostatic hyperplasia, with the interim analysis based on the change in PISS from baseline to 12 weeks in all 479 patients treated in the study. The independent data monitoring committee found no safety concerns.