Transcept Pharmaceuticals announced today that the FDA issued a Complete Response Letter regarding the New Drug Application (NDA) for Intermezzo® (zolpidem tartrate sublingual tablet). The NDA, submitted by Transcept in September 2008, seeks approval to market Intermezzo® for use as-needed for the treatment of insomnia when a middle of the night awakening is followed by difficulty returning to sleep. In the Complete Response Letter the FDA stated that it believes Transcept has submitted substantial evidence of effectiveness for the use of Intermezzo® in the as-needed treatment of insomnia characterized by difficulty returning to sleep after awakening in the middle of the night. The FDA further recognized that the Intermezzo® data submitted by Transcept did not indicate significant next day residual effects. However, the FDA indicated that the intended use of Intermezzo® in the middle of the night represents a unique insomnia indication and dosing strategy for which safety has not been previously established. The FDA requested additional data demonstrating that Intermezzo®, when taken as directed in the middle of the night, would not present an unacceptable risk of residual effects, with particular reference to next day driving ability. The FDA also expressed two concerns regarding the possibility of patient dosing errors in the middle of the night that could lead to next day residual effects. Specifically, the FDA has asked Transcept to address methods to avoid inadvertent dosing with less than four hours of bedtime remaining, and inadvertent re-dosing in a single night. Based upon the content of the letter, it is possible that Transcept will need to conduct one or more additional safety studies. Transcept will request a meeting with the FDA to discuss specific requirements for approval. Glenn A. Oclassen, President and Chief Executive Officer of Transcept, commented, "Transcept is committed to making this important new potential therapy available to insomnia patients. We will continue to work closely with the FDA to address their questions and define the path forward for Intermezzo®."