Cellegy Pharmaceuticals has announced that it has received an approvable letter from the FDA for Cellegesic (nitroglycerin ointment). The letter stated that before the company's new drug application (NDA) may be approved, Cellegy must conduct another clinical trial to demonstrate efficacy at a level deemed statistically significant by the agency. The letter indicated that the agency is requiring an additional study because it believes the results of the three trials conducted to date do not provide substantial evidence that the drug is effective, and provides a number of comments on the results previously presented and recommendations concerning the design and protocol of the additional required study.

Cellegesic, for the treatment of anal fissures, was the subject of an FDA not approvable letter in December 2004. An amended NDA, containing new analyses, was resubmitted in April 2005, which resulted in a review by the FDA's Cardio-Renal Advisory Committee in April 2006. Cellegesic has been under review at the FDA since then.