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XenoPort and the NIAAA Announce Clinical Trial Agreement to Study HORIZANT as a Potential Treatment for Alcohol Use Disorder

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XenoPort, Inc. (Nasdaq:XNPT) and the National Institute on Alcohol Abuse and Alcoholism (NIAAA) announced today that they have entered into an agreement to conduct a clinical trial of HORIZANT(R) (gabapentin enacarbil) Extended-Release Tablets as a potential treatment for alcohol use disorder (AUD). Under the terms of the agreement, XenoPort will supply clinical trial material and the NIAAA will conduct and pay all other expenses associated with the proposed clinical trial of HORIZANT. XenoPort will have access to study results generated under the proposed clinical trial to support potential regulatory filings for HORIZANT.

“Current medications for alcohol dependence are effective for some, but not all, patients. New medications are needed to provide effective therapy to a broader spectrum of alcohol dependent individuals,” said George F. Koob, Ph.D., director of the NIAAA, a part of the National Institutes of Health. “Prior clinical studies of gabapentin, the active metabolite of the molecule called gabapentin enacarbil, have shown positive results in patients with AUD. We believe that the time is right to conduct a multi-site, well-controlled clinical trial.”

The study is planned to be a randomized, double-blind, placebo-controlled clinical trial of the safety and efficacy of HORIZANT in patients who have AUD but are abstinent at treatment initiation. The study is expected to have a treatment period of six months and to enroll approximately 350 patients beginning in the first half of 2015.

XenoPort and the NIAAA are planning to meet with the U.S. Food and Drug Administration (FDA) Division of Anesthesia, Analgesia and Addiction Products in the fourth quarter of 2014 to discuss the trial design and the possibility of utilizing the results of this trial as the basis for a potential supplemental new drug application (sNDA) submission for HORIZANT for the maintenance of abstinence from heavy drinking of alcohol in patients with AUD.

Ronald W. Barrett, Ph.D., chief executive officer of XenoPort, Inc., stated, “Our goal in designing gabapentin enacarbil was to address the pharmacokinetic limitations of gabapentin. We are hopeful that the predictable high bioavailability, rapid titration and low fluctuating gabapentin blood levels with twice-daily administration associated with HORIZANT may enable successful treatment of AUD and look forward to working with the NIAAA on this important study.”

Background of Gabapentin in AUD Clinical Studies

Data from clinical trials indicate that oral gabapentin may reduce alcohol craving and alcohol withdrawal symptoms. In addition, single-site clinical trials have also shown that in alcohol dependent patients who are abstinent at treatment initiation, gabapentin delayed the onset to heavy drinking and improved the symptoms of insomnia. In these studies, gabapentin was generally well-tolerated.


Discovered and developed by XenoPort, gabapentin enacarbil is a prodrug of gabapentin. In the United States, XenoPort has six issued patents listed in the FDA’s Orange Book for HORIZANT that have expiration dates between 2022 and 2029.

About Alcohol Use Disorder (AUD)

AUD affects about 17 million people in the United States and has an estimated societal cost of approximately $225 billion each year, primarily from lost productivity, but also from healthcare and property damage costs.

About XenoPort

XenoPort, Inc. is a biopharmaceutical company focused on developing and commercializing a portfolio of internally discovered product candidates for the potential treatment of neurological disorders. XenoPort is currently commercializing HORIZANT in the United States and developing its novel fumaric acid ester product candidate, XP23829, as a potential treatment for patients with moderate-to-severe chronic plaque-type psoriasis and/or relapsing forms of multiple sclerosis. REGNITE(R) (gabapentin enacarbil) Extended-Release Tablets is being marketed in Japan by Astellas Pharma Inc. XenoPort recently granted exclusive world-wide rights for the development and commercialization of its clinical-stage oral product candidate, arbaclofen placarbil, to Reckitt Benckiser Pharmaceuticals, Inc. for all indications. XenoPort’s pipeline of product candidates also includes a potential treatment for patients with Parkinson’s disease.

To learn more about XenoPort, please visit the website at

Forward-Looking Statements

This press release contains “forward-looking” statements, including, without limitation, all statements related to the potential clinical development of HORIZANT; the suitability of gabapentin enacarbil as a potential treatment of AUD; planned regulatory discussions and the timing thereof; the possibility of utilizing the proposed study as the basis for an sNDA filing for HORIZANT for the maintenance of abstinence from alcohol in patients with alcohol dependence; the expected study design and enrollment in the proposed clinical trial of gabapentin enacarbil, and the timing thereof; XenoPort’s expectation that top-line results of the proposed clinical trial of gabapentin enacarbil would be available in the second half of 2016; and the therapeutic and commercial potential of gabapentin enacarbil. Any statements contained in this press release that are not statements of historical fact may be deemed to be forward-looking statements. Words such as “believe,” “expected,” “goal,” “hopeful,” “may,” “planning,” “possibility,” “potential,” “proposed,” “will” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon XenoPort’s current expectations. Forward-looking statements involve risks and uncertainties. XenoPort’s actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, the difficulty and uncertainty of pharmaceutical product development and the uncertain results and timing of clinical trials and other studies, including the risk that success in preclinical testing and early clinical trials do not ensure that later clinical trials will be successful, and that the results of clinical trials by other parties may not be indicative of the results in trials that XenoPort or its partners may conduct; XenoPort’s and the NIAAA’s ability to successfully advance gabapentin enacarbil development and to conduct clinical trials in the anticipated timeframes, or at all; the risk that the completion of clinical trials for gabapentin enacarbil may be delayed or terminated as a result of many factors, including delays in patient enrollment; that gabapentin enacarbil may require significant additional clinical testing prior to any possible additional regulatory approvals; the uncertainty of the FDA’s review process and other regulatory requirements; the uncertainty of protecting and expanding XenoPort’s intellectual property rights, including the risk that patent rights may not provide XenoPort with sufficient protection against competitive products or otherwise cover commercially valuable products or processes; XenoPort’s dependence on collaborative partners; and the uncertain therapeutic and commercial value of XenoPort’s product candidates. These and other risk factors are discussed under the heading “Risk Factors” in XenoPort’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2014 filed with the Securities and Exchange Commission on August 7, 2014. XenoPort expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in the company’s expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.

HORIZANT, REGNITE and XENOPORT are registered trademarks of XenoPort, Inc.

Source code: XNPT2C

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