Preclinical data of new acamprosate prodrug to be presented at International Fragile X Conference

XenoPort, Inc. (Nasdaq:XNPT) announced today that it has discovered a novel prodrug that has the potential to improve significantly the blood concentration of acamprosate compared with the currently approved formulation of acamprosate. Preclinical data on this new product candidate will be presented tomorrow at the National Fragile X Foundation's 12^th International Fragile X Conference in Detroit, Michigan.

“Our financial resources are limited and prevent immediate advancement of this preclinical product candidate. However, we are exploring options for further development, including corporate partners or grants from private or public institutions.”

Acamprosate calcium has been marketed under the trade name Campral since 2004 for the maintenance of abstinence in alcoholics. A recently published open-label study of acamprosate calcium in three adult Fragile X syndrome patients with co-occurring autism spectrum disorder was conducted by Craig A. Erickson, M.D., Assistant Professor of Psychiatry at the Indiana University School of Medicine. This study showed evidence of therapeutic benefit in all patients as measured by the Clinical Global-Impression of Improvement Scale. Treatment with acamprosate calcium was also associated with reported improvement in linguistic communication. Two of the three patients experienced gastrointestinal (GI) disturbances, which affected the dosing regimen and led to temporary drug discontinuation in one patient.

Poor absorption from the GI tract is thought to contribute to GI disturbance associated with oral dosing of acamprosate calcium. Low oral bioavailability (~10%) and variable exposure may also limit its efficacy.

Preclinical trial results that will be presented tomorrow indicate that oral dosing of XenoPort's new acamprosate prodrug has the potential to significantly improve blood concentrations of acamprosate compared with oral dosing of acamprosate calcium. In addition, efficient absorption of the prodrug from the colon was observed and suggests that an extended-release oral formulation would be possible. XenoPort's prodrug of acamprosate could offer the potential for meaningful improvements over oral acamprosate calcium that may include a decrease in GI disturbance, reduced dosing frequency and more consistent (and potentially higher) blood levels of acamprosate.

Ronald W. Barrett, Ph.D., chief executive officer of XenoPort, stated, "Further studies of XenoPort's acamprosate prodrug are required, but we are hopeful that improved bioavailability and tolerability could prove useful in treating the symptoms of patients with Fragile X syndrome." Barrett continued, "Our financial resources are limited and prevent immediate advancement of this preclinical product candidate. However, we are exploring options for further development, including corporate partners or grants from private or public institutions."

XenoPort has filed patent applications directed to the acamprosate prodrug's composition of matter, methods of synthesis and uses in the United States and other jurisdictions.

SOURCE XenoPort, Inc.