(Research Triangle Park, N.C.) GlaxoSmithKline (NYSE: GSK) and XenoPort, Inc. (Nasdaq: XNPT) today announced that the U.S. Food and Drug Administration (FDA) has extended the original Prescription Drug User Fee Act (PDUFA) goal date for its review of the New Drug Application (NDA) for GSK1838262/XP13512 (gabapentin enacarbil) to February 9, 2010. The original PDUFA date for this NDA review was November 9, 2009.

The FDA determined that a Risk Evaluation and Mitigation Strategy (REMS) was necessary for GSK1838262. In response to FDA’s request, GSK submitted a proposed REMS. The FDA accepted this submission as a solicited major amendment to the GSK1838262 NDA. The FDA has the option to extend the PDUFA goal date when a sponsor submits a major amendment that provides a substantial amount of new data not previously reviewed by the FDA.

GlaxoSmithKline – one of the world’s leading research-based pharmaceutical and healthcare companies – is committed to improving the quality of human life by enabling people to do more, feel better and live longer. For further information please visit www.gsk.com.

XenoPort is a biopharmaceutical company focused on developing a portfolio of internally discovered product candidates that utilize the body’s natural nutrient transport mechanisms to improve the therapeutic benefits of existing drugs. XenoPort is developing its lead product candidate in partnership with Astellas Pharma Inc. and GSK. XenoPort’s product candidates are being studied for the potential treatment of restless legs syndrome, gastroesophageal reflux disease, migraine headaches, neuropathic pain, spasticity related to spinal cord injury and Parkinson’s disease. To learn more about XenoPort, please visit the Web site at www.XenoPort.com.