"Patients treated with PRX302 continue to show a good response to treatment with stabilization of symptoms and maintenance of voiding pattern," commented Dr. Peter Pommerville, co-principal investigator at Can-Med Clinical Research Centre in Victoria, B.C. "The fact that symptom improvement has been maintained to 9 months indicates the lasting effect of PRX302 on prostate tissue."
Therapeutic activity of PRX302 was assessed using standardized symptom indices, namely, International Prostate Symptom Score (IPSS) and Quality of Life Scores (QoL). IPSS assesses the severity of seven key symptoms of BPH, (incomplete emptying, frequency, intermittency, urgency, weak stream, straining and nocturia). The QoL score is measured on a scale from 0-6 with 0 defined as "delighted" and 6 defined as "terrible" with respect to patient quality of life due to BPH.
At 6-months post-treatment the mean IPSS values improved by an average of 6.4 points from 19.1 +/- 4.3 at screening to 12.7 +/- 5.2 at day-180 post treatment (p= 0.0009), with 6 of 15 patients showing a 10 point or greater improvement in IPSS values. In the 6 men for whom 9-month data are available at this time, IPSS values improved by an average of 6.1 points. QoL scores improved by 2.0 points from an average of 4.5 +/- 1.1 at screening to 2.5 +/- 1.4 by day-180 (p= 0.0002). In the 6 men for whom 9-month data is available, QoL scores improved by an average of 2.3 points by day-270. The mean prostate volume decreased by over 22%, from 46.4 cc at screening to 35.8 cc at day-180 post-treatment and by 20% from 49.6 cc at screening to 39.7 cc at day-270 post-treatment.
As reported on January 3, 2008, despite a 14-fold escalation in dose, no safety issues were identified and the maximum tolerated dose was not reached in this study.
"We are very pleased to see that the majority of men treated in this study continue to show very impressive results even 9-months post-treatment," said Dr. Fahar Merchant, President and Chief Executive Officer of Protox. "The sustained symptomatic improvement is compelling especially when a reduction in IPSS by greater than four points is deemed to be highly clinically significant. These results further substantiate our belief that PRX302 represents a significant opportunity for the treatment of a condition that affects the quality of life of approximately 50 percent of men over the age of 60."
Based on the encouraging data from this study, Protox has initiated a Phase 2 clinical trial in men with moderate to severe BPH. The intent of this Phase 2 study will be to optimize dosing in order to fully exploit the therapeutic potential of PRX302, while maintaining its excellent safety profile.
About the Study
This study was an open-label, multi-centre, dose escalation study where the primary endpoint was safety and tolerability following a single intra-prostatic administration of PRX302. The secondary endpoint was to determine therapeutic activity as measured by the change in IPSS throughout the study, when compared to screening. In addition, changes in QoL scores and prostate volume were also monitored. A total of 15 patients with moderate to severe BPH were treated in this trial. The dose was increased 14-fold between cohort 1 and cohort 4, keeping the dosing volume constant, whereas one additional cohort received cohort 1 dose at a 4-fold higher volume. Patient parameters at screening were as follows: age - 64.8 years (range: 52-82); prostate size - 41.3 mL (range: 30.0-80.1); IPSS - 19.1 (range: 12-26); QoL - 4.3 (range: 3- 6). Most patients treated in this study were either refractory or intolerant to oral therapy.
About BPH
BPH is a common urological condition characterized by painful and bothersome symptoms that include difficulty in initiating a urine stream, a sense of urgency, leaking, dribbling and presence of blood in the urine. The condition affects over 50 million men throughout North America, Europe and Japan. More than half of all men will have symptoms of BPH by age 60 and as many as 90% may suffer from BPH after the age of 70. Current drug therapies only provide symptomatic relief and may trigger a range of side effects including impotence and hypotension. Surgical options such as TURP (transurethral resection of the prostate), which constitute the second-largest item in the US Medicare budget, can cause impotence, incontinence as well as other more serious procedure-related effects. According to Wood Mackenzie (2007), the market opportunity for therapies used to treat BPH was US $5.5 billion in drug therapies and US $4 billion in surgical procedures.
About Protox
Protox Therapeutics is a leader in advancing novel, receptor targeted fusion proteins. Two novel drug candidates derived from the company's INxinTM and PORxinTM platforms are being developed in three clinical programs. 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. Phase 2a clinical trials evaluating PRX302 (PORxin) for the treatment of localized prostate cancer and benign prostatic hyperplasia (enlarged prostate) have also been initiated. 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.
For further information
James Beesley, Director, Investor Relations, Protox Therapeutics, (604) 484-0975, jbeesley@protoxtherapeutics.com Michael Moore, Investor Relations, Equicom Group, (416) 815-0700 x 241, mmoore@equicomgroup.com
Source: Protox Therapeutics Inc.
