Actavis confirms generic Exelon Patch patent challenge; InnoPharma debuts generic Vistide in USA

US generics drugmaker Actavis (NYSE: ACT, formerly trading as Watson) confirmed that it has filed with the US Food and Drug Administration an amendment to its Abbreviated New Drug Application for rivastigmine Transdermal System to include the 13.3mg per 24 hours dosage strength. Actavis' ANDA product is a generic version of Swiss drug major Novartis' (NOVN: VX) Exelon Patch, a prescription medicine used to treat people with mild to moderate dementia associated with Alzheimer's or Parkinson's disease.

Novartis filed suit against Watson on March 7, in the US District Court for the District of Delaware seeking to prevent Actavis from commercializing its 13.3mg/ 24-hour strength product prior to the expiration of certain US patents. The law suit was filed under the provisions of the Hatch-Waxman Act, resulting in a stay of final FDA approval of Watson's 13.3mg/ 24 hr strength ANDA product for up to 30 months from the date that Novartis received notice of Actavis' ANDA amendment filing or until final resolution of the matter before the court, whichever occurs sooner, subject to any other exclusivities.

Actavis previously filed an ANDA with the FDA seeking approval to market Rivastigmine Transdermal System patch 4.6mg/24 hr and 9.5mg/24 hr, and was subsequently sued by Novartis in November 2011. That application is subject to a separate 30-month stay.