Transcept Pharmaceuticals Inc., of Point Richmond, Calif., said it received the official complete response letter (CRL) from the FDA, two days after a phone call with the agency indicating there were still outstanding safety issues related to insomnia candidate Intermezzo (zolpidem tartrate sublingual tablet), specifically the drug's next-day residual effects. Transcept, which is seeking to market Intermezzo specifically for middle-of-the-night awakenings, previously conducted a next-day driving study to address the agency's concerns, but said the latest CRL raised concerns relating to differing blood levels of zolpidem among patients and how those might translate into next-day impairment.