FDA Rejects Insomnia Drug Suvorexant
Agency cites dosage and safety concerns (July 1)
The FDA has declined to approve the new drug application (NDA) for suvorexant, an investigational medicine for the treatment of insomnia.
In its Complete Response Letter, the agency stated that:
- 10 mg should be the starting dose for most patients, and must be available before suvorexant can be approved.
- 15-mg and 20-mg doses would be appropriate in patients in whom the 10-mg dose is well-tolerated but not effective.
- For patients taking concomitant moderate cytochrome P450 (CYP) 3A4 inhibitors, a 5-mg dose would be necessary.
In addition, the FDA determined that the safety data do not support the approval of suvorexant 30 mg and 40 mg.
Based on an initial review of the letter, the drug’s developer (Merck) has determined that additional clinical studies of suvorexant 10 mg will not be necessary. However, manufacturing studies will be required to advance the 10-mg dosage form. Merck will discuss with the FDA whether additional studies will be required to support the 5-mg dose.
If approved, suvorexant would be the first in a new class of drugs, called orexin receptor antagonists, for use in patients with insomnia.
Source: Merck; July 1, 2013.