Positive top-line results from Protox Therapeutics' Phase 2b study of PRX302 announced

Protox Therapeutics Inc. (TSX: PRX), a leader in the development of receptor targeted fusion proteins, today announced positive top-line results from its double-blinded placebo controlled Phase 2b study of PRX302 (study name: TRIUMPH) in patients with moderate to severe benign prostatic hyperplasia (BPH), a painful and bothersome urological condition that affects more than 50 million men worldwide. The study achieved its primary clinical endpoint of a statistically significant improvement in International Prostate Symptom Score (IPSS) for patients treated with PRX302 versus subjects receiving placebo>

"We are very excited about the results of the TRIUMPH study," said Dr. Fahar Merchant, President and Chief Executive Officer of Protox. "We believe that PRX302 has an immense commercial opportunity and look forward to sharing these impressive data with our potential partners."

"The future for new drug development is to create molecules that target the organ or cell of interest and affect it as needed with minimal collateral damage. PRX302 is an excellent example of such a designer drug that targets cells producing PSA which is limited to the prostate gland," commented Dr. Mostafa M. Elhilali, OC, M.D., Ph.D. Chief Co-Principal Investigator and Stephen Jarislowsky Chair of Urology at McGill University. "The study results from this placebo controlled trial showed that injecting PRX302 in the prostate produced the desired effects with minimal side effects which is quite exciting. Furthermore, improvements in symptoms were also associated with improvements in flow rates and Quality of Life measures."

Study Design: -------------

TRIUMPH was a double-blinded, placebo-controlled, multi-centre Phase 2b study in subjects with moderate to severe BPH. Enrolment criteria included baseline IPSS scores greater than or equal to 15, a maximum urinary flow rate (Qmax) of less than 12 milliliters per second and prostate volume between 30 and 100 milliliters. Each subject was treated with either PRX302 (3 microgram/mL) or placebo at a volume equivalent to 20 percent of the total prostate volume via a single ultrasound guided injection into each lobe of the prostate.

The trial's primary clinical endpoint of the study was to determine the efficacy of PRX302, as demonstrated at 90 days post-treatment, by a statistically significant improvement in IPSS from baseline when compared to placebo. IPSS is a validated primary clinical endpoint used to assess the treatment benefit in BPH trials. This index is measured on a 0 to 35 scale with 0 being defined as having no problems and 35 defined as the high end of severe symptoms.

Study Results: --------------

Of the 73 per protocol efficacy evaluable subjects, 52 received PRX302 and 21 received placebo. The PRX302 arm showed an average IPSS improvement at 90 days of 9.1 (+/- 5.9) points versus an average IPSS improvement of 5.8 (+/- 5.4) points for the placebo arm, a statistically significant improvement of 3.3 points>

A sub-group analysis was performed for subjects with severe BPH (baseline IPSS(greater than)22,>

No significant safety issues were identified in this study. There were no drug related serious adverse events or Grade 3 or greater adverse events reported in the study. PRX302 related adverse events were mild to moderate, transient in nature (resolved within days) and localized to the urinary tract. In addition, no sexual dysfunction was reported in any of the subjects.

A total of 92 subjects were enrolled on a 2-to-1 basis (treatment to placebo) and randomized based on their baseline IPSS and prostate size. At 90 days, the number of per protocol efficacy evaluable subjects was 21 (mean age of 64.5 years) of the 31 that were dosed at baseline in the placebo arm and 52 (mean age of 63.7 years) of the 61 dosed at baseline in the PRX302 arm. The decrease in efficacy evaluable subjects was due to protocol violations, medical interventions, or patient withdrawal and included three subjects that needed surgery to treat BPH (all from the placebo arm).

Detailed results from this study will be presented by Professor Mostafa Elhilali during a podium session at the Annual Meeting of the American Urological Association to be held in San Francisco, May 29 - June 3, 2010.