XenoPort, Inc. (Nasdaq: XNPT) announced today that additional data from
a Phase 2 clinical trial demonstrated that arbaclofen placarbil
(AP), also known as XP19986, significantly reduced symptoms in
gastroesophageal reflux disease (GERD) patients who previously
experienced at least a partial response to proton pump inhibitor (PPI)
therapy. The data were presented today by Nimish B. Vakil, M.D., FACG,
of the University of Wisconsin Medical School at the Digestive Disease
Week 2009 annual meeting in Chicago, IL.
The new data demonstrated that AP monotherapy in GERD patients who had
previously experienced at least a partial response to a PPI provided
statistically significant benefits versus placebo on a number of
important endpoints, including reduction in regurgitation episodes and
complete relief of heartburn and/or regurgitation symptoms during the
final week of the trial.
“We are pleased that this proof-of-concept study demonstrated that AP
monotherapy reduces heartburn and regurgitation episodes in a relevant
population of GERD patients,” said Ronald W. Barrett, Ph.D., XenoPort’s
chief executive officer. “Given these encouraging results, we plan to
initiate in 2009 a Phase 2 clinical trial of AP as adjunctive therapy in
patients who remain symptomatic while on PPI therapy.”
In many GERD sufferers, the lower esophageal sphincter (a combination of
muscles located between the stomach and esophagus) does not function
appropriately, allowing reflux of stomach contents into the esophagus.
Acid-suppressing treatments such as PPIs do not treat this underlying
cause of GERD, and patients on these drugs may continue to experience
symptoms. Reflux can cause discomfort and a diminished quality of life;
over time, inadequate treatment of reflux can lead to esophageal damage
and, in rare cases, cancer.
“Despite the widespread use of acid-suppressing therapies, many GERD
patients continue to experience troublesome symptoms. A new medicine
with a different mechanism of action could address the unmet medical
needs of GERD patients who remain symptomatic while on PPI therapy,”
said Dr. Vakil, a clinical professor of medicine and a principal
investigator of the AP trial. “Inhibiting reflux by modulating the lower
esophageal sphincter, the mechanism by which AP treatment leads to
symptom reduction, holds great promise, and the results of this trial
are encouraging both in terms of efficacy and tolerability.”
Study Design
The four-week, randomized, double-blind, placebo-controlled clinical
trial enrolled 156 subjects at 16 sites in the United States. Enrolled
subjects had GERD symptoms occurring at least three days a week and had
either no history of taking PPIs (PPI-naïve patients; N=58) or a history
of at least a partial symptom response to PPI therapy (PPI-experienced
patients; N=98). Enrolled subjects were required to discontinue prior
therapy for GERD.
