Horizant is an investigational treatment for moderate-to-severe primary Restless Legs Syndrome developed by Xenoport and licensed to GlaxoSmithKline.
Depomed noted that unlike Horizant, its proprietary extended release formulations of gabapentin are not new chemical entities that require additional carcinogenicity or other toxicology studies.
Depomed also expects to file an NDA for DM-1796 in the first quarter of this year under Section 505(b) of the Federal Food, Drug and Cosmetic Act. The company has received final meeting minutes from the FDA for a pre-NDA meeting related to DM-1796 for postherpetic neuralgia (PHN) held in December 2009.
The firm is of the opinion that no additional carcinogenicity studies will be required for the DM-1796 NDA because it will reference the same toxicology package that formed the basis of the approval of Neurontin (gabapentin) for epilepsy and postherpetic neuralgia.
Depomed said that Gabapentin is a well-characterised compound that has been marketed for epilepsy since 1993 and PHN since 2002. The compound has not shown a carcinogenicity signal in post-marketing experience involving approximately 20 million prescriptions annually.