XenoPort, Inc. (Nasdaq: XNPT) announced today that it will present data on its investigational and marketed therapies for neurological diseases at the 66 th Annual Meeting of the American Academy of Neurology (AAN) in Philadelphia. Data being presented include the results from a clinical trial evaluating the safety, tolerability and pharmacokinetics of XP23829, an investigational prodrug of monomethyl fumarate (MMF). XP23829 is currently being evaluated as a potential treatment for moderate-to-severe chronic plaque type psoriasis and may be a potential treatment for relapsing forms of multiple sclerosis (MS).

Additionally, data will be presented for gabapentin enacarbil, the active ingredient in HORIZANT ® (gabapentin enacarbil) Extended-Release Tablets. HORIZANT is approved by the U.S. Food and Drug Administration (FDA) for the treatment of moderate-to-severe primary restless legs syndrome (RLS) in adults and for the management of postherpetic neuralgia (PHN) in adults. These data include new post-hoc analyses of results from the gabapentin enacarbil clinical trial program.

“At XenoPort, we are committed to providing novel therapies for patients who continue to be in need of effective treatment options,” said Richard Kim, M.D., senior vice president of clinical development and medical affairs, and chief medical officer of XenoPort, Inc. “The data being presented at AAN support the treatment benefits of HORIZANT, demonstrate the potential for XP23829 and reinforce our dedication to people living with chronic, debilitating diseases. In particular, we are excited that the data for XP23829 support the advancement of this product candidate into potential Phase 2 development in moderate-to-severe chronic plaque type psoriasis patients, a program that we believe will ultimately guide selection of doses for a potential Phase 3 program in moderate-to-severe chronic plaque type psoriasis and/or relapsing forms of MS.”

The titles and presentation times for XenoPort’s abstracts are as follows:

  • Steady State Pharmacokinetics of Formulations of XP23829, a Novel Prodrug of Monomethyl Fumarate (MMF), in Healthy Subjects;
    • Poster P1.188; Monday, April 28; 3:00 p.m.
  • Lymphocyte and Eosinophil Responses in Healthy Subjects Dosed with Tecfidera and XP23829, a Novel Fumaric Acid Ester (FAE);
    • Poster P1.201; Monday, April 28; 3:00 p.m.

  • The Efficacy of Gabapentin Enacarbil (GEn) in Adult Patients with Severe Primary Restless Legs Syndrome (RLS): Pooled Analyses From 3 Randomized Trials
    • Poster I3-1.009; Monday, April 28; 8:00 a.m.
    • Poster P5.290; Wednesday, April 30; 3:00 p.m.
  • Peripheral Edema and Weight Gain in Adult Patients with Painful Diabetic Peripheral Neuropathy (DPN) Receiving Gabapentin Enacarbil (GEn) or Pregabalin Enrolled in a Randomized Phase 2 Trial
    • Poster I6-1.004; Tuesday, April 29; 1:00 p.m.
    • Platform S20.005; Tuesday, April 29; 3:15 p.m.
  • The Effect of Prior Exposure to Dopamine Agonists (DA) on Response to Treatment with Gabapentin Enacarbil (GEn) in Adult Patients with Moderate-to-Severe Primary Restless Legs Syndrome (RLS): Pooled Analyses from 3 Randomized Trials
    • Poster P5.289; Wednesday, April 30; 3:00 p.m.

About XP23829

XP23829, an experimental drug discovered and currently under development by XenoPort, is a fumaric acid ester compound that is a prodrug of MMF. Fumaric acid ester compounds have shown immuno-modulatory and neuroprotective effects in cell-based systems and preclinical models of disease. XP23829 is in the fumaric acid ester class of compounds that 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 in Germany and widely used for the treatment of patients with psoriasis. XenoPort has completed Phase 1 development of XP23829 and plans to initiate a Phase 2 clinical trial in patients with moderate-to-severe chronic plaque type psoriasis by mid-year.

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


HORIZANT, discovered and developed by XenoPort, was approved in the United States in July 2011 for the treatment of moderate-to-severe primary RLS in adults and in June 2012 for the management of PHN in adults. The most common adverse reactions for adult patients with moderate-to-severe primary RLS receiving HORIZANT were somnolence/sedation, dizziness, headache, nausea and fatigue. The most common adverse reactions for adult patients with PHN taking HORIZANT were dizziness, somnolence/sedation, headache, nausea and fatigue.

HORIZANT is protected by a composition-of-matter patent that runs to 2022, with patent term extension likely into 2025.

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 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 pipeline of product candidates also includes potential treatments for patients with spasticity related to spinal cord injury and Parkinson's disease. To learn more about XenoPort, please visit the website at www.XenoPort.com.

Forward-Looking Statements

This press release contains “forward-looking” statements, including, without limitation, all statements related to our current strategy for advancing the XP23829 clinical development program, including the initiation or conduct of planned or potential future clinical trials and the timing thereof; the suitability of XP23829 as a potential treatment for moderate-to-severe chronic plaque type psoriasis and/or relapsing forms of MS; potential immuno-modulatory and neuroprotective effects for fumaric acid ester compounds; the potential for HORIZANT patent term extension; and other statements that are not historical facts. 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,” “likely,” “plans,” “may,” “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: risks related to 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 does 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 or initiate clinical trials in the anticipated timeframes, or at all; the uncertainty of the FDA’s review process and other regulatory requirements, including with respect to obtaining regulatory clearance to initiate planned or potential clinical trials; the risk that XenoPort may be unable to obtain patent term extension for HORIZANT; XenoPort's dependence on potential future collaborative partners; XenoPort’s need for and the availability of resources to develop XP23829 and support XenoPort’s operations; the uncertain therapeutic and commercial value of HORIZANT and XP23829; as well as risks related to future opportunities and plans, including the inherent uncertainty of pharmaceutical product development. These and other risk factors are discussed under the heading "Risk Factors" in XenoPort’s Annual Report on Form 10-K for the year ended December 31, 2013, filed with the Securities and Exchange Commission on February 28, 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.


HORIZANT ® (gabapentin enacarbil) Extended-Release Tablets


HORIZANT ® (gabapentin enacarbil) is a prescription medicine used to:
  • treat adults with moderate-to-severe primary Restless Legs Syndrome (RLS). HORIZANT is not for people who need to sleep during the daytime and stay awake at night.
  • manage pain from damaged nerves (postherpetic neuralgia) that follows healing of shingles (a painful rash that comes after a herpes zoster infection) in adults.

  • Do not drive after taking your dose of HORIZANT until you know how it affects you, including the morning after you take it. Do not operate heavy machinery or do other dangerous activities until you know how HORIZANT affects you. HORIZANT can cause sleepiness, dizziness, slow thinking, and can affect your coordination. Ask your healthcare provider when it is okay to do these activities.
  • Do not take other medicines that make you sleepy or dizzy while taking HORIZANT without talking to your healthcare provider. Taking HORIZANT with these other medicines may make your sleepiness or dizziness worse.
  • HORIZANT may cause suicidal thoughts or actions in a very small number of people (about 1 in 500). Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings. Call your healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you:
    • thoughts or actions about suicide, self-harm, or dying; attempt to commit suicide
    • new or worsening depression or anxiety; or feeling agitated
    • new or worse restlessness or panic attacks
    • new or worse trouble sleeping (insomnia); or irritability
    • acting aggressive, being angry, or violent; acting on dangerous impulses
    • an extreme increase in activity or talking (mania); other unusual changes in mood or behavior
  • Do not stop taking HORIZANT without first talking to your healthcare provider.Suicidal thoughts or actions can be caused by things other than medicines. If you have these thoughts or actions, your healthcare provider may check for other causes.
  • HORIZANT may cause a serious or life-threatening allergic reaction that may affect your skin or other parts of your body such as your liver or blood cells. You may or may not have a rash with these types of reactions. Call a healthcare provider right away if you have any of the following symptoms: skin rash, hives, fever, swollen glands that do not go away, swelling of your lips or tongue, yellowing of your skin or eyes, unusual bruising or bleeding, severe fatigue or weakness, unexpected severe muscle pain, or frequent infections. These symptoms may be the first signs of a serious reaction. A healthcare provider should examine you to decide if you should continue taking HORIZANT.
  • HORIZANT is not the same medicine as gabapentin (for example, Neurontin® and Gralise®). HORIZANT should not be used in their place. Do not take these or other gabapentin products while taking HORIZANT.
  • Before taking HORIZANT, tell your healthcare provider if you:
    • have or have had kidney problems or are on hemodialysis
    • have or have had depression, mood problems, or suicidal thoughts or behavior
    • have or have had seizures
    • have a history of drug abuse
    • have any other medical conditions
    • are pregnant or plan to become pregnant. It is not known if HORIZANT will harm your unborn baby. Talk to your healthcare provider if you are pregnant or plan to become pregnant while taking HORIZANT. You and your healthcare provider will decide if you should take HORIZANT while you are pregnant
    • are breastfeeding or plan to breastfeed. Your body turns HORIZANT into another drug (gabapentin) that passes into your milk. It is not known if this can harm your baby. You and your healthcare provider should decide if you will take HORIZANT or breastfeed
    • drink alcohol
  • Do not drink alcohol while taking HORIZANT because it may increase the risk of side effects.
  • Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Taking HORIZANT with certain other medicines can cause side effects or affect how well they work. Do not start or stop other medicines without talking to your healthcare provider.
  • Do not stop taking HORIZANT without talking to your healthcare provider first. If you stop taking HORIZANT suddenly, you may develop side effects.
  • The most common side effects of HORIZANT include dizziness, sleepiness, and headache. Tell your healthcare provider about any side effect that bothers you or does not go away. These are not all the possible side effects of HORIZANT. For more information, ask your healthcare provider or pharmacist.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088. See Medication Guide.

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