In March 2017, we initiated a second Phase 2 clinical trial to confirm the dose and optimize the delivery of topsalysin for the treatment of clinically significant localized prostate cancer. This study utilizes previously obtained MRI images of each patient’s prostate mapped to real time 3D ultrasound to target the delivery of topsalysin directly into and around a pre-identified clinically significant tumor. The primary objective of the study is safety and tolerability of an injection of topsalysin and the key efficacy variable is focal ablation of a clinically significant lesion on biopsy after six months.
We have reported safety and biopsy findings from our Phase 2b clinical trial following a single administration of topsalysin. A single administration of topsalysin continues to be safe and well-tolerated and demonstrated an ability to ablate prostate cancer tumor cells with 10/37 patients (27%) demonstrating a clinical response of which 6 were complete ablations.
The Phase 2b prostate cancer clinical trial represents the first trial designed to allow qualified patients to receive a second administration of topsalysin six months after initial treatment. On December 17, 2018 we announced top-line safety and biopsy results from the ten patients who received a second administration of study drug, which appeared to be safe and generally well-tolerated. Additional benefit was not observed on targeted biopsy six months after re-treatment with a second administration of topsalysin. The decision to include a second administration of topsalysin in any future clinical studies is under review by the Company.