San Diego specialty drugmaker Somaxon Pharmaceuticals, (NASDAQ: SOMX said today the FDA turned down its application to market a new drug for insomnia. Somaxon says the FDA raised a number of issues related to the interpretation of the efficacy data in its new drug application.
The company says the FDA did not specifically ask it to conduct additional clinical trials of its drug candidate, doxepin (Silenor). But the FDA asked the company to address the possibility that the drug may prolong the heart’s QT interval—a key measure of the heart’s electrical rhythm.
Somaxon says it plans to collect additional data from already completed clinical trials that evaluated the drug’s potential effect on the heart’s electrical cycle. Results of the test previously disclosed by Somaxon show doxepin had no effect on prolonging the QT interval when administered at doses of 6 milligrams or 50 milligrams.
The company noted that doctors have been prescribing doxepin for more than 35 years for the treatment of depression and anxiety at dosages of 75 milligrams to 300 milligrams a day. Somaxon is seeking approval for a low-dose oral tablet formulation at 1 milligram, 3 milligrams, and 6 milligrams for treating insomnia.
Somaxon says a discussion with the FDA will be necessary to gain a complete understanding of the concerns raised by the agency. “As we continue to seek approval of Silenor, we will continue to take measures to conserve our cash and will evaluate financing alternatives available to us,” Chief Executive Richard Pascoe said in a statement.
Somaxon shares dropped more than 50 percent after the bell, losing $1.12 in after-hours trading before settling at $1.02 at 6:20 pm ET.