Protox Announces Positive Final Results from BPH Study
VANCOUVER, Jan. 3 /CNW/ - Protox(TM) Therapeutics Inc. (TSX-V:
PRX), a leader in advancing novel, targeted protein toxin
therapeutics for the treatment of cancer and other proliferative
diseases, today announced positive final results from its Phase 1
study evaluating PRX302 in patients with benign prostatic
hyperplasia (BPH), a common condition among the aging male
population. The trial results indicate that PRX302 is safe and well
tolerated and shows very promising signs of therapeutic activity
for the treatment of BPH.
"The impact of PRX302 in the quality of life of most patients has
been dramatic," commented Dr. Peter Pommerville, co-principal
investigator at Can-Med Clinical Research Centre in Victoria, B.C.
"In addition to the rapid treatment response, the effect of PRX302
continued to improve with time and showed that symptomatic relief
was sustained over time. Furthermore, patient satisfaction with the
single ten minute office-based minimally invasive treatment for BPH
is high."
"We are very pleased with these data as PRX302 continues to deliver
impressive results in the clinic," said Dr. Fahar Merchant,
President and
Chief Executive Officer of Protox. "In addition to the excellent
safety and tolerability profile, PRX302 has demonstrated
substantial symptomatic benefit in most patients who failed
existing oral therapies."
Study Design:
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
International Prostate Symptom Score (IPSS) throughout the study,
when compared to screening. In addition, changes in Quality of Life
(QoL) scores, prostate volume and uroflow parameters 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.
Study Results:
Despite a 14-fold escalation in dose, no safety issues were
identified and the maximum tolerated dose was not reached in this
study. Results indicate that PRX302 was well tolerated with no
serious adverse events observed. Treatment related adverse events
were generally reported as being mild, local and transient in
nature.
Therapeutic activity of PRX302 was evaluated at day-30 and day-90
post-treatment using standardized symptom indices, namely, IPSS and
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.
Treatment related symptomatic relief was rapid and substantial
benefits were noticed by day-30 post-treatment. Both symptom scores
(IPSS and QoL) continued to show further improvements in all
cohorts at the end of the active study period (day-90
post-treatment) indicating a potential for sustained benefit
following a single treatment with PRX302.
Across all treatment groups, IPSS scores showed a statistically
significant improvement from screening to Day 30 (p (less than)
0.01) and
continued to Day 90 post-treatment (p (less than) 0.001). The mean
IPSS values improved by an average of 5.8 points from 19.1 +/- 4.3
at screening to 14.3 +/- 5.7 at day-30 post treatment. By day-90,
IPSS improved by an average of 8.5 points (10.6 - 5.9) with 8 of 15
patients showing a 10 point or greater improvement in IPSS values.
The improvements were observed across all seven symptom sub-scores,
each decreasing by at least 30%. Although early, these results are
compelling especially when a reduction in IPSS by greater than four
points is deemed to be highly clinically significant.
Improvement in QoL scores were observed in all five cohorts.
Independent of the treatment group, QoL scores improved from an
average of 4.3 +/- 1.1 at screening to 2.5 +/- 1.6 by day-30 (p
(less than) 0.01) and continued to show a 50% improvement by day-90
(QoL = 2.1 - 1.6; p (less than) 0.01)).
Furthermore, prostate volume decreased in all cohorts. Irrespective
of cohort assignment, the mean prostate volume decreased by over
26% from 41.6 cc at screening to 30.5 cc at day-90 post-treatment
(p (less than) 0.05).
Based on the encouraging data from this study, plans are currently
underway to commence a Phase 2 BPH clinical trial in the first
quarter of
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 (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 PRX302
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 (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. 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).
NO REGULATORY AUTHORITY HAS APPROVED OR DISAPPROVED THE CONTENT OF
THIS RELEASE. THE TSX VENTURE EXCHANGE DOES NOT ACCEPT
RESPONSIBILITY FOR THE ADEQUACY OR ACCURACY OF THIS
RELEASE.
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.
-30-
/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/
Posted: January 2008
