Glenmark Pharmaceuticals and Sun Pharmaceutical Industries have received approval to sell generic versions of Novartis’ epilepsy drug Trileptal with a 180-day shared exclusivity in the US market. 

Trileptal, chemically known as oxcarbazepine, recorded sales of around $643 million in the US alone in the year to June 2007, according to IMS Health.  Trileptal is Novartis' blockbuster drug indicated for use as monotherapy or adjunctive therapy in the treatment of partial seizures. The product generated annual revenues of USD640 million in the USA (IMS–2006). The patent for Trileptal had expired in 2005, following which the innovator Novartis had filed for a new patent for the product, which is set to expire only in 2018. 

 Sun has received the final approval from the USFDA for its ANDA to manufacture and market its generic version of Novartis' Trileptal (oxcarbazepine). Being one of the first to file an ANDA for generic Trileptal® with a para IV certification, Sun has been awarded a 180-day marketing exclusivity for the product to be shared with Glenmark and Roxane. Trileptal has annual revenues of USD640 million in the USA. Sun is planning to launch the product shortly, while Glenmark has already launched the product  in three strengths — 150 mg, 300 mg and 600mg  in the USA on October 9, 2007.