SOUTH SAN FRANCISCO, Calif., Oct. 30 /PRNewswire-FirstCall/ —
Pain Therapeutics, Inc., (Nasdaq: PTIE), a medical research company, today
announced a pilot program directed at the treatment of irritable bowel
syndrome (IBS) with low-dose opioid antagonist. IBS is a common, chronic
disorder characterized by recurrent, unexplained abdominal pain. Each year,
up to 30 million Americans, mostly women, suffer from symptomatic pain
associated with IBS.
"There are no unrestricted prescription drugs on the market today to treat
patients with IBS," said Remi Barbier, president and chief executive officer
of Pain Therapeutics. "This pilot program offers hope to millions of
Americans who suffer from symptomatic pain associated with IBS and marks a
milestone in broadening the clinical use of the Company's technology."
Pain Therapeutics' new IBS program consists of an Investigational New Drug
(IND) application, plans to initiate a pilot clinical study and further
research into the pharmacology and mechanism of action of low-dose opioid
antagonist therapy for IBS patients. Two issued U.S. patents protect the
Company's rights specifically toward methods of treating IBS patients with
"IBS has traditionally been viewed as an abnormality in gastrointestinal
motility, but it is becoming increasingly clear that IBS patients may also be
suffering from neuronal dysfunction," said Nadav Friedmann, Ph.D., M.D., Pain
Therapeutics' chief operating officer. "We believe the use of specific,
non-toxic low-dose opioid antagonist could elicit broad clinical interest as
the neurology of IBS becomes more widely understood."
Pilot Study, December 2002
Pain Therapeutics has filed an IND application with the FDA to study the
use of low-dose opioid antagonist in IBS patients. As a next step, the
Company plans to conduct a pilot study in a large medical center in Israel.
This pilot study is aimed at validating the biological significance and the
safety of using low-dose opioid antagonist drug therapy in 50 patients
diagnosed with IBS. The Company expects to announce the initiation of this
pilot study in December 2002 and to complete patient enrollment in the second
quarter of 2003. If successful, the results of this study may allow the
Company to enter into a major drug development program aimed at product
approval. The cost to complete this pilot study is expected to be
Results of Independent Study
An independent clinical investigator at the Albert Einstein College of
Medicine evaluated the use of low-dose opioid antagonists in IBS patients. In
an open label study, 21 patients with IBS diagnosed by the Rome II criteria
received a single bedtime dose of low-dose opioid antagonist for six weeks.
Seventeen (17) of 21 patients reported an average reduction of 82 percent in
pain and all gastrointestinal indices of IBS as measured by visual analog
scales of pain and other symptoms. IBS related pain returned to responders in
14 to 45 days after termination of treatment. Each responder was subsequently
allowed to re-initiate therapy with low-dose opioid antagonist, and each again
demonstrated a positive response. Since then, some of the clinical
investigator's patients have remained on low-dose opioid antagonist therapy
for over two years.
Exclusive Rights to Issued Patents
Pain Therapeutics holds exclusive, worldwide commercial rights in a family
of patents and applications directed to the long-term treatment of IBS
patients with opioid antagonists, including issued U.S. Patent No. 6,194,382
and No. 6,395,705. The Company's patent portfolio now includes eight issued
U.S. patents that cover both composition of matter and use claims.
Novel Mechanism of Action
As with most disorders of central nervous system, the etiology of IBS
remains speculative. Academic research suggests that IBS represents an
abnormality of the intestinal opioid system. Opioid receptor cells that line
the intestinal wall normally present a balance of inhibitory and excitatory
responses to the presence of endogenous opioid agonists. In IBS patients,
this cellular balance may be degraded. In such cases, excitatory signals
predominate over inhibitory signals. Hyper-excitatory signaling in the gut
produces intense intestinal pain and other abdominal conditions commonly seen
in IBS patients. According to this putative mechanism of action, treating IBS
patients with low-dose opioid antagonists may block excessive excitatory
signals, thus alleviating the abdominal pain experienced by IBS patients.
About Irritable Bowel Syndrome (IBS)
IBS is a chronic, painful disorder of the intestines that leads to major
changes in bowel habits. IBS causes some patients to have constipation,
diarrhea, or in some cases both. The cause of IBS is not known, and as yet
there is no cure. People with chronic IBS may be unable to attend social
events, hold a job, or travel away from home. Over 10 percent of the U.S.
population suffers from IBS. For unknown reasons, IBS predominantly affects
About Pain Therapeutics, Inc.
We are a medical research company specializing in the discovery and
development of novel proprietary painkillers. We believe our lead drug
candidates, OxyTrex(TM) and MorViva(TM), may offer more pain relief (with no
increase in side-effects) and lower tolerance/dependence, withdrawal effects
or addiction potential compared to conventional forms of oxycodone and
morphine. Our proprietary painkillers are currently in various phases of
clinical testing, including Phase II trials. Pain Therapeutics is traded on
Nasdaq under the symbol PTIE.