Protox announces positive final data from prostate cancer study

    VANCOUVER, Nov. 1 /CNW/ - Protox Therapeutics Inc. (TSX-V:PRX) today
announced positive final results from its Phase 1 clinical trial evaluating
PRX302 in patients with localized, recurrent prostate cancer following
radiation failure. The trial results, an extension of those released on
July 10, 2007, indicate that PRX302 is well tolerated and shows promising
signs of therapeutic activity.
    "In addition to demonstrating that PRX302 was well tolerated, early signs
of therapeutic activity seen at this stage are promising," said Dr. Scott
Coffield, Principal Investigator from the lead site, Scott and White Memorial
Hospital. "These observations are encouraging and are suggestive of the
potential clinical benefit of PRX302, particularly in light of the recurrent
cancer seen in those patients who had progressive disease following radiation
    This study was intended to examine the safety and tolerability of PRX302
as a primary endpoint and therapeutic activity as a secondary endpoint in
patients with biopsy proven localized recurrent prostate cancer following
radiation therapy who showed signs of disease progression as evidenced by
rising levels of PSA (prostate specific antigen). A total of 24 patients were
treated in this trial. The average age of patients in the study was 69.6
(range: 58-86).
    Protox concluded that despite a 100-fold escalation in dose, the maximum
tolerated dose (MTD) was not reached in this study while evidence of
therapeutic activity was observed. As reported in July, no significant safety
issues were encountered in this clinical trial. No serious adverse events were
reported relating to PRX302 and most adverse events reported were associated
with the injection procedure, rating no higher than Grade 1 (mild). Assessment
of potential therapeutic activity was determined by prostate biopsies at 
day-30 post-treatment and by measuring serial PSA levels.
    A comparison of prostate biopsies taken at baseline and day-30
post-treatment showed 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 no detectable cancer in their day-30 biopsy. Results showed that in 21
of the 24 patients a decrease in PSA levels below screening levels were
observed at 30 days or longer post-treatment while in 15 of 24 patients PSA
levels continued to be below screening levels or stable at 90 days or longer.
Comparison of PSA levels pre- and post-treatment showed a desirable trend
towards an increase in PSA doubling time (PSADT) in 19 of 24 patients and a
decrease or stable PSA velocity (PSAV) in 17 of 24 patients, both of which are
positive outcomes for the patient.
    "We are very pleased that the results from this Phase 1 study of PRX302
demonstrate its potential as a treatment for localized prostate cancer," said
Dr. Samuel Denmeade, Chief Scientific Officer of Protox and co-inventor of
PRX302. "These data, taken together with the encouraging interim data on our
Phase 1 BPH study, further substantiate the promise of PRX302."
    The company anticipates that a Phase 2a study evaluating PRX302 for the
treatment of patients with locally recurrent prostate cancer following primary
radiation therapy will commence before the end of the year. The objective of
this study is to amplify the anti-cancer activity of PRX302 by using various
intra-prostatic injection regimens. The assessment of therapeutic activity
will be based on changes in PSA levels, PSAV, PSADT and tumor burden (prostate
biopsies) following treatment. The study will also evaluate the safety and
tolerability of the different regimens of injection.

    Conference call

    Protox will host a conference call and live webcast today at 11:00 a.m.
E.T. to discuss these results. To access the conference call by telephone,
dial 416-644-3420 or 1-800-733-7571. Please connect approximately ten minutes
prior to the beginning of the call to ensure participation. The conference
call will be archived for replay until November 8, 2007 at midnight. To access
the archived conference call, dial 416-640-1917 or 1-877-289-8525 and enter
the reservation number 21252499 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 Prostate Cancer

    Prostate cancer is a leading cause of cancer death in North American men.
One in every six men is diagnosed with prostate cancer during their lifetime.
The American Cancer Society estimates that during 2007 approximately 219,000
new cases of prostate cancer will be diagnosed and over 27,000 men will die
from the disease in the U.S. Current treatment options for localized prostate
cancer include surgery and radiation therapy. Serious side effects are
associated with these therapies including erectile dysfunction, incontinence,
urinary dysfunction and bowel problems.

    About Protox

    Protox Therapeutics is a leader in advancing novel, targeted protein
toxin therapeutics for the treatment of cancer and other proliferative
diseases. Two novel drug candidates derived from the company's INxin(TM) and
PORxin(TM) 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 1 clinical trials
evaluating PRX302 (PORxin) have been completed for the treatment of localized
prostate cancer and benign prostatic hyperplasia (enlarged prostate).


    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:

For further information: James Beesley, Director, Investor Relations,
Protox Therapeutics, (604) 688-0199,; Michael
Moore, Investor Relations, Equicom Group, (416) 815-0700 x 241,

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