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XenoPort Announces Initiation of a Phase 2 Clinical Trial of XP23829 in Patients With Psoriasis

SANTA CLARA, Calif.--(BUSINESS WIRE)--June 23, 2014 XenoPort, Inc. announced today that it has initiated a Phase 2 clinical trial of XP23829, its proprietary investigational next-generation fumaric acid product candidate. The trial is a multi-center, randomized, double-blind, placebo-controlled study designed to assess the efficacy and safety of XP23829 as a potential treatment of patients with moderate-to-severe chronic plaque-type psoriasis.

Richard Kim, M.D., XenoPort's chief medical officer, stated, "We are excited to take this next step in the advancement of the development of XP23829. From this Phase 2 trial, we hope to further our understanding of the efficacy, safety and tolerability of XP23829. In addition, the study is designed to generate information on the effect of dose and treatment duration on potential reduction in psoriatic lesions and modulation of sub-populations of blood immune cells. Based on historical enrollment rates of psoriasis studies conducted in the U.S., we expect top-line results of the trial in the third quarter of 2015."

XenoPort expects to enroll approximately 200 subjects in this trial, which is being conducted in the United States. The study will include a screening and washout phase of up to four weeks, a 12-week treatment phase and a four-week post-treatment phase. Eligible study subjects will be randomized to placebo or one of three treatment arms of XP23829: 400 mg or 800 mg once daily or 400 mg twice daily. The primary endpoint of the study will examine the percent change in Psoriasis Area and Severity Index (PASI) score from baseline at the end of week 12. Secondary endpoints will include the proportion of subjects who achieve a reduction of 75% or greater from baseline in PASI (PASI-75) score and subjects who achieve a Static Physicians Global Assessment (sPGA) score of "clear" or "almost clear."

Ronald W. Barrett, Ph.D., XenoPort's chief executive officer, further commented, "Fumaric acid ester drugs have been previously shown to be effective in psoriasis, although there are no products in the class that are approved by the U.S. Food and Drug Administration (FDA) for this indication. We believe that this trial will begin to define the distinguishing attributes of XP23829 as a potential best-in-class drug. These attributes could potentially include convenient once-a-day dosing, reduced flushing and gastrointestinal side effects and possibly more rapid onset and increased magnitude of efficacy. We believe that the results from this trial, if positive, could allow advancement of XP23829 directly into Phase 3 studies as a potential treatment for psoriasis. In addition, based on the strong correlation of results in psoriasis and relapsing forms of multiple sclerosis (MS) observed for other fumaric acid based drugs, we believe that this study could also form a basis for moving XP23829 into Phase 3 studies as a potential treatment for relapsing forms of MS."

About XP23298

XP23829, an investigational drug discovered and currently under development by XenoPort, is a fumaric acid ester compound that is a prodrug of monomethyl fumarate (MMF). Fumaric acid ester compounds have shown immuno-modulatory and neuroprotective effects in cell-based systems and preclinical models of disease. The fumaric acid ester class of compounds includes TECFIDERA, which was approved in March 2013 by the FDA for the treatment of patients with relapsing forms of MS, and FUMADERM, which is approved and widely used in Germany for the treatment of patients with psoriasis.

XP23829 is protected by a U.S. composition-of-matter patent currently has an expiration date of 2029.

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® (gabapentin enacarbil) Extended-Release Tablets 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 MS. REGNITE® (gabapentin enacarbil) Extended-Release Tablets is being marketed in Japan by Astellas Pharma Inc. XenoPort's product candidate, arbaclofen placarbil, has been licensed to Reckitt Benckiser Pharmaceuticals Inc., who plans to initially test arbaclofen placarbil for its ability to suppress alcohol cravings, reduce alcohol intake and to possibly facilitate maintenance of abstinence in alcohol dependent people. 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 advancing the development of XP23829; the suitability of XP23829 as a potential treatment for moderate-to-severe chronic plaque-type psoriasis and/or relapsing forms of MS; the potential for XP23829 to be developed into a best-in-class drug; XenoPort's belief regarding potential distinguishing attributes of XP23829; expected enrollment in the Phase 2 clinical trial of XP23829; XenoPort's expectation that it will obtain top-line results of the Phase 2 clinical trial of XP23829 in the third quarter of 2015; XenoPort's belief that the results of the Phase 2 clinical trial could allow the advancement of, or form a basis for moving, XP23829 into Phase 3 studies; and the therapeutic and commercial potential of XP23829. 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," "could," "expect," "hope," "may," "possibly," "potential," "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 may conduct; XenoPort's ability to successfully advance XP23829 development and to conduct clinical trials in the anticipated timeframes, or at all; the risk that the completion of clinical trials for XP23829 may be delayed or terminated as a result of many factors, including delays in patient enrollment; the risk that XenoPort's belief regarding potential distinguishing attributes of XP23829 may not be observed or validated in clinical testing; that XP23829 will require significant additional clinical testing prior to any possible regulatory approvals and failure could occur at any stage of its development; 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 potential future collaborative partners; the availability of resources to develop XenoPort's product candidates and to support XenoPort's operations; 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 March 31, 2014 filed with the Securities and Exchange Commission on May 9, 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.

Source: XenoPort, Inc.

Posted: June 2014