Sophiris Bio, Inc. announced the biopsy data at 6 months for the first seven patients to complete the Phase 2a proof-of-concept study in localized prostate cancer. A review of the biopsy data from the first seven men to complete the study showed that four patients experienced a response to treatment: One patient experienced complete ablation of the tumor where no evidence of the treated tumor remained on a targeted biopsy at 6 months; three patients experienced either a reduction in the maximum cancer core length or a reduction in Gleason pattern; three patients had no response to treatment. This one-time administration of topsalysin directly into a pre-identified clinically significant tumor appears to be well tolerated with no serious adverse events and no new safety signals being reported.

This is consistent with safety observed in the 365 patients that have been treated with topsalysin in the Company's BPH program to date. The ongoing Phase 2a proof of concept study is a single-center, open-label study at University College London, which is well known for the focal treatment of prostate cancer in the UK. In this study, previously obtained multiparametric magnetic resonance images (mpMRIs) of each patient's prostate tumor lesions are mapped to real-time three-dimensional transrectal ultrasound.

These images are used to guide the injection of topsalysin to treat a single, histologically-proven, clinically significant prostate cancer lesion. The primary objective of the study is safety and tolerability, and the key efficacy variable is the change in the treated lesion on targeted biopsy after 6 months. The study is designed to assess whether topsalysin has the potential to provide patients with clinically significant, localized, low to intermediate risk prostate cancer a tissue-sparing cancer treatment that carries little in the way of side effects.

A total of 18 patients were enrolled and treated in this study. Sophiris expects to have final data on all patients by the end of the second quarter of 2016.