In the Notice Letter, Teva alleges that three patents associated with Tenofovir Disoproxil – US Patent numbers 5922695, 5977089 and 6043230, and one patent associated with Tenofovir Disoproxil Fumarate – US Patent number 5935946 – owned by Gilead Sciences are invalid, and/or will not be infringed by Teva’s manufacture for use or sale of the product described in its ANDA submission.
Gilead is currently reviewing the Notice Letter and has 45 days from the date of receipt to commence a patent infringement lawsuit against Teva. Such a lawsuit would restrict the FDA from approving Teva’s ANDA for up to 30 months or until a district court decision that is adverse to Gilead, whichever occurs first.
Viread is currently protected by four patents, which are listed in the FDA’s approved drug products list, and all four patents would need to be invalidated or expired before a generic version of Viread could be marketed. The US Patent & Trademark Office (PTO) confirmed the patentability of these four Viread patents in 2008.
Gilead currently has a lawsuit pending against Teva in response to the latter’s attempts to seek approval for generic versions of Truvada (emtricitabine and tenofovir disoproxil fumarate) and Atripla (efavirenz 600mg/emtricitabine 200mg/tenofovir disoproxil fumarate 300mg). It is based on allegations that two emtricitabine patents are invalid, unenforceable and/or will not be infringed by Teva’s manufacture for use or sale of its generic product.