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Protox Announces Positive Clinical Data from Prostate Cancer Study

VANCOUVER, British Columbia, July 10, 2007 /CNW/ - Protox Therapeutics Inc. (TSX-V:PRX) today  announced positive top-line results from its Phase 1 clinical trial evaluating  PRX302 in patients with localized, recurrent prostate cancer following  radiation failure. The trial results indicate that PRX302 is safe and well  tolerated and shows promising signs of therapeutic activity following a single  intra-prostatic treatment.      

"The completion of the PRX302 Phase 1 trial is encouraging from two  perspectives," said Dr. Scott Coffield, Principal Investigator from the lead  site, Scott and White Memorial Hospital. "First, there was therapeutic benefit  demonstrated through overall PSA reduction in study patients, as well as a  reduction in the number of positive biopsies after treatment. Second, there  was no significant adverse side effect profile at the highest dose of PRX302  given to patients in this trial."      

"It is heartening to see promising results at this stage of the clinical  development program in a patient population which has limited therapeutic  options," said Dr. Fahar Merchant, President and Chief Executive Officer of  Protox. "These data support our heightened confidence regarding the potential  of PRX302 for the treatment of not only prostate cancer, but also BPH, which  is currently being evaluated in an ongoing Phase I trial."      

This study is intended to examine the safety, tolerability and  therapeutic activity of PRX302 in patients with localized recurrent prostate  cancer who show signs of disease progression as evidenced by rising levels of  PSA (prostate specific antigen) following radiation treatment. Using a  well-established, image-guided technique, PRX302 was administered directly  into the prostate. A total of 24 patients were treated in this trial. Protox  has concluded that despite a 100-fold escalation in dose, the maximum  tolerated dose (MTD) was not reached in this study while encouraging signs of  therapeutic activity were observed.      

No significant safety issues relating to PRX302 treatment were  encountered in this clinical trial. One patient in the study, who met  inclusion criteria in spite of having borderline liver abnormalities, showed a  transient rise in liver enzymes (Grade 3 on the National Cancer Institute's  5-stage grading scale) that quickly returned to screening levels. An expanded  cohort was enrolled at this dose in order to collect additional safety data.  No safety issues were observed in any patients within the expanded cohort or  in further cohorts that received higher doses. In summary, no serious adverse  events were reported relating to PRX302 and all other adverse events reported  were mostly associated with the injection procedure, rating no higher than  Grade 1 (mild).      

Assessment of potential therapeutic activity was determined by measuring  PSA levels throughout the study and conducting prostate biopsies at 30 days  post-treatment. PSA is one of the most widely recognized disease markers in  prostate cancer and levels of PSA in the blood are used in the diagnosis of  prostate cancer, monitoring cancer progression and tracking patient responses  to its treatment.      

A comparison of prostate biopsies taken at baseline and at 30 days  post-treatment shows that 18 of the 24 patients tested in this trial had a  decrease in the percentage of cancer-positive biopsies. Three of the patients  showed a complete absence of cancer in their day 30 biopsy.      

Two specific measurement indicators, PSA doubling time (PSADT) and PSA  velocity (PSAV), are key parameters in predicting clinical progression,  metastasis and mortality in patients with prostate cancer. Of the 24 patients  tested in this study, 90 day PSA data is available for 15 patients at this  time. Comparison of PSA levels pre- and post-treatment shows a clear and  desirable trend towards an increase in PSADT (15 of 15 patients) and a  decrease in PSAV (11 of 15 patients), both of which are very positive outcomes  for the patient. Results show that in 10 of 15 patients PSA levels were below  baseline at 90 days or longer post-treatment. In 14 of the 15 patients, a  decrease in PSA levels was observed during at least one of the, 30-, 60- or  90-day follow-up intervals.      

The company expects that a final report that will include top-line PSA  data with expanded analysis of PSADT and PSAV will be available for release in  October. Plans are underway to commence a Phase 2 study before the end of the  year.   

Conference call   

Protox will host a conference call and live webcast today at 12:00 p.m.  E.T. to discuss these results. To access the conference call by telephone,  dial 416-644-3414 or 1-800-732-9307. Please connect approximately ten minutes  prior to the beginning of the call to ensure participation. The conference  call will be archived for replay until August 10, 2007 at midnight. To access  the archived conference call, dial 416-640-1917 or 1-877-289-8525 and enter  the reservation number 21240373 followed by the number sign. A live audio webcast of the conference call will be available at Please connect at least ten minutes prior to the  conference call to ensure adequate time for any software download that may be  required to join the webcast. The webcast will be archived at the above  website for 30 days.   

About Protox   

Protox Therapeutics is a leader in advancing novel, targeted protein  toxin therapeutics for the treatment of cancer and other proliferative  diseases. The company is actively developing two distinct but complementary  platforms, INxin(TM) and PORxin(TM), and currently has four programs in  clinical development. A Phase 2a clinical trial evaluating PRX321 (INxin) for  the treatment of primary brain cancer has been completed and the product  candidate has received Fast Track Designation and Orphan Drug Status from the  US FDA. In addition, a Phase 1 clinical trial evaluating PRX321 for the  treatment of patients with renal cell carcinoma and non-small cell lung cancer  has been completed. Patient enrollment has been completed for a Phase 1  clinical trial evaluating PRX302 (PORxin) for the treatment of localized  prostate cancer. A Phase 1 clinical trial evaluating PRX302 for the treatment  of benign prostatic hyperplasia (enlarged prostate) is ongoing.   


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) 688-0199,; Michael  Moore, Investor Relations, Equicom Group, (416) 815-0700 x 241,


Posted: July 2007