Protox announces positive 12 month Phase 2 BPH results
TORONTO, Sept. 10 /CNW/ - Protox Therapeutics Inc. (TSX: PRX), a leader in the development of receptor targeted fusion proteins, today announced positive 12 month data from its open-label Phase 2 study of PRX302 in males with moderate to severe benign prostatic hyperplasia (BPH). The study results indicate that those patients who received an optimal dose of PRX302 continued to demonstrate significant symptomatic relief at 12 months following a single treatment. "We are very excited to see a twelve point improvement in IPSS in this patient group even after twelve months following a single treatment," said Dr. Fahar Merchant, President and Chief Executive Officer of Protox. "This level of symptomatic improvement is almost double that seen with oral therapies and comparable to many surgical procedures, further strengthening our belief in the immense commercial opportunity of PRX302. We look forward to sharing these data as well as the upcoming results from our 92 patient double-blinded placebo controlled Phase 2b BPH study with our potential commercial partners." "The results from this study are impressive and demonstrate the durable impact that this novel therapeutic has on potentially improving the quality of life of patients suffering with BPH," commented Dr. Peter Pommerville, co-principal investigator at Can-Med Clinical Research in Victoria, B.C. "PRX302 continues to demonstrate the ability to improve urinary tract symptoms while maintaining a good safety profile. Based on the results to date, I believe that PRX302 has definite potential to address a number of the inadequacies seen with existing BPH therapies, namely sexual dysfunction and other treatment related side effects."
Study Results: --------------
The International Prostate Symptom Score (IPSS) is a validated accepted clinical end-point used to assess the treatment benefit in BPH clinical studies. This index is measured on a 0-35 scale with 0 defined as having no problems and 35 defined as the high end of severe symptoms. In this Phase 2 open-label volume optimization study, 13 of the 18 patients received the optimum PRX302 dosing of (greater than)-1mL per deposit. A total of 11 of the 13 patients were evaluable at 12-months and continued to show a statistically significant and sustained improvement in IPSS of 12.1 points (p= 0.0003) representing a 55% improvement when compared to screening. In addition to IPSS, Quality of Life (QoL) scores improved significantly by an average of 3.18 points or 67% (p(less than)0.0001) at 12 months post-treatment. Furthermore, prostate volume at 12 months post-treatment decreased significantly by 29% (p=0.02). Finally, the average maximum urine flow rate (Qmax) increased from 10.7mL/sec at screening to 15.2 mL/sec at 12 months for a 42% improvement in patients receiving the optimum dose. No safety issues were identified in this study, as increasing volumes of PRX302 were seen to be well tolerated. No PRX302 related serious adverse events or Grade 3 or greater adverse events have been reported to date. The 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 has been reported in any of the subjects dosed to date. Detailed 12-month results from this Phase 2 open-label clinical trial will be presented by Dr Pommerville at the 30th World Congress of the Societe Internationale d'Urologie to be held in Shanghai from November 1-5, 2009.
Study Design: -------------
This was a single-arm, open-label, multi-centre, Phase 2 study in which increasing volumes of PRX302, at a fixed concentration (3 mg/mL), was administered into the prostates of men with moderate to severe BPH. Three cohorts of six subjects each received PRX302 at volumes equivalent to 10%, 20% or 30% of prostate volume. The intended volume for each subject was administered via a single injection consisting of three deposits into each lobe of the prostate under ultrasound guidance. Therapeutic activity was measured by the change in IPSS when compared to screening. In addition, changes in QoL scores and prostate volume, Qmax were also monitored. A total of 18 patients who were refractory, intolerant or unwilling to use alpha-blockers were enrolled in this study. Patient parameters at screening were as follows: age - 66.1 years (range: 49-80); prostate size - 49.2 cc (range: 30.0-74.0 cc); IPSS - 20.2 (range: 13-30); QoL - 4.5 (range: 3-6).
PRX302 is the lead drug in the company's PORxin(TM) technology platform. PORxin drugs are pore-forming pro-drugs that are activated by specific proteases produced at elevated levels on the surface of target cells. PRX302 has been generated by engineering the naturally occurring toxin proaerolysin so that it is activated by prostate-specific antigen (PSA), an enzyme that is overproduced in patients suffering from prostate cancer and BPH. Once activated, the drug punches holes in the cells causing the contents to leak out and ultimately cell death.
BPH is a common urological condition characterized by painful and bothersome symptoms that include difficulty in initiating a urine stream, a sense of urgency, dribbling, incomplete emptying of the bladder, waking several times during the night to urinate and sometimes the presence of blood in the urine. More than half of all men will have symptoms of BPH by the age of 60 and as many as 90% may suffer from BPH after the age of 80. Current oral therapies mainly provide symptomatic relief, may take months before they take effect and can trigger a range of side effects including sexual dysfunction and hypotension. It is estimated that in the seven largest global markets approximately 10 million men are treated annually with oral therapies and these products encompass approximately U.S. $3 billion of sales each year. Surgical options, including minimally invasive procedures, can cause sexual dysfunction, incontinence as well as other more serious procedure-related effects. Surgical measures can require significant recovery time and may require catheterization for up to several weeks post-treatment. Nearly 600,000 surgical procedures are conducted annually in the seven largest markets.
Protox Therapeutics is a leader in advancing novel, receptor targeted fusion proteins. Two novel drug candidates derived from the company's INxin(TM) and PORxin(TM) platforms are being developed in three clinical programs. Protox's lead program, PRX302 (PORxin), is currently being studied in a Phase 2b placebo controlled trial to treat benign prostatic hyperplasia (BPH or enlarged prostate). Positive Phase 2a results treating BPH patients were released at the end of 2008 and a phase 2a clinical trial evaluating PRX302 for the treatment of localized prostate cancer is ongoing. A Phase 2a clinical trial evaluating PRX321 (INxin) for the treatment of primary brain cancer has been completed and the drug has received Fast Track Designation and Orphan Drug Status from the US FDA and EMEA. Protox is also collaborating with the U.S. National Institutes of Health (NIH) on a research program focused on the discovery of next generation fully human targeted therapeutics.
Certain statements included in this press release may be considered forward-looking. Such statements involve known and unknown risks, uncertainties and other factors that may cause actual results, performance or achievements to be materially different from those implied by such statements, and therefore these statements should not be read as guarantees of future performance or results. All forward-looking statements are based on Protox' current beliefs as well as assumptions made by and information currently available to Protox and relate to, among other things, anticipated financial performance, business prospects, strategies, regulatory developments, market acceptance and future commitments. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release. Due to risks and uncertainties, including the risks and uncertainties identified by Protox in its public securities filings; actual events may differ materially from current expectations. Protox disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.
Posted: September 2009