2007-10-03
Protox Therapeutics Inc.

    VANCOUVER, Oct. 3 /CNW/ - Protox Therapeutics Inc. (TSX-V:PRX) today
announced that it has completed recruitment of patients for its Phase 1
clinical trial evaluating PRX302 in males with benign prostatic hyperplasia
(BPH) and reported positive interim data from this study. The findings to date
indicate that PRX302 is safe and well tolerated and shows promising signs of
therapeutic activity.
    "Patients with bladder outlet obstruction and lower urinary tract
symptoms due to BPH are keen to seek non-surgical options," said Dr. Peter
Pommerville, co-principal investigator at Can-Med Clinical Research Centre in
Victoria, B.C. "Very often they first choose oral medication to relieve their
symptoms. The current standard of care is a combination of an alpha-blocker
and a 5 alpha-reductase inhibitor. These medications, although effective, take
a long period of treatment time to show benefit and can cause significant side
effects, such as altering sexual function. The patients with BPH that I have
treated with PRX302 consider this to be an excellent alternative to prostate
surgery and better than the standard oral therapy because results are almost
immediate. PRX302 reduces symptoms without sexual side effects. Nocturia
(waking at night to urinate) has been reduced from up to 6 times a night to
less than once per night in some patients. The symptom reduction has been
maintained in these patients over the period of follow-up."
    "We are very pleased to have completed recruitment of this study ahead of
schedule and while it is still early in the clinical program we are very
encouraged by these results," said Dr. Fahar Merchant, President and Chief
Executive Officer of Protox.
    This study is intended to examine the safety, tolerability and
therapeutic activity of PRX302 in patients with moderate to severe BPH. Using
a well-established, image-guided technique, PRX302 was administered directly
into the prostate in a relatively simple procedure performed in the
urologist's office. A total of 12 patients in four cohorts (three patients per
cohort) were treated in this study protocol. The average age of the patients
in this study is 62.5 years (range: 52-82). Most of the patients treated in
this study were either refractory or intolerant to oral therapy. Protox has
concluded that despite a 14-fold escalation in dose, the maximum tolerated
dose was not reached in this study. Results indicate that PRX302 is safe and
well tolerated with no serious adverse events observed. Any adverse events
reported were mild in nature and all transient.
    In nine out of 12 patients for whom 30-day data is available at this
time, encouraging signs of therapeutic activity were observed. International
Prostate Symptom Scores (IPSS) are commonly used to assess the efficacy of
therapies used to treat BPH. This symptom index was developed and validated by
the American Urological Association and includes seven categories covering
frequency, nocturia, weak urinary stream, hesitancy, intermittence, incomplete
emptying and urgency. 30-day data has shown a clear and desirable trend
towards decreased (improved) IPSS scores. The patients treated at the lowest
dose in this study (cohort 1) showed an average one point (5%) decrease in
IPSS scores, while those treated at the intermediate doses (cohorts 2 and 3)
both averaged seven point decreases of 39% and 35% respectively. Quality of
life scores (QOL) are another symptom index used to assess the improvement of
patients that have undergone BPH therapy. This index is measured on a scale
from 0-6 with 0 defined as "delighted" and 6 defined as "terrible." At
screening, most subjects had QOL scores ranging from 4 to 6, suggesting mostly
"dissatisfied", "unhappy" and "terrible" feelings regarding the state of their
urinary symptoms. In all of the nine patients for whom 30-day data is
available, QOL scores decreased compared to screening. Patients in cohort 1, 2
and 3 showed an average 54%, 63% and 60% decrease respectively.
    Dr. Pommerville added, "The procedure is simple, safe, can be performed
in a physicians office and more importantly, the beneficial effects of
treatment are observed in less than two weeks. The marked reduction in
symptoms has had a profound improvement in patients' quality of life. The
avoidance of surgery and sexual side effects caused by oral therapy, the rapid
onset of improvement in obstructive symptoms and allowing patients to get back
to their regular routine the day after the procedure appeals to men suffering
from this disease. Two patients who are keen golfers were able to play the day
after PRX302 treatment, attesting to the simplicity of the procedure."
    The company anticipates that data from cohort 4 (the highest dose) and
top-line data from the study will be released before the end of the year and
plans to commence a Phase 2 study in early 2008.

    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. Left untreated, it can
result in serious and possibly irreversible bladder damage. 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
(2006), the market opportunity for therapies used to treat BPH was
US .9 billion.

    About PRX302

    PRX302 is the lead drug in the company's PORxin(TM) technology platform.
PORxin drugs are 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 to create a potent
agent with a distinct mode of action. The drug has been engineered so that it
is activated by prostate-specific antigen (PSA), an enzyme that is
overproduced in patients suffering from prostate cancer and BPH (benign
prostatic hyperplasia or enlarged prostate). Once activated, the drug punches
holes in the cells causing the contents to leak out and ultimately cell death.

    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 clinical programs
in development. A Phase 2a clinical trial into the use of 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. In
addition, a Phase 1 trial has been completed for PRX321 to treat patients with
renal cell carcinoma and non-small cell lung cancer. Patient enrollment has
been completed for a Phase 1 clinical trial into the use of PRX302 (PORxin)
for the treatment of localized prostate cancer and benign prostatic
hyperplasia (enlarged prostate).

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    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