Under the recently passed Leahy-Smith America Invents Act (“AIA”), generic drug manufacturers will be able to use post grant review (“PGR”) to effectively invalidate or constrain pharmaceutical patents. The efficiency of PGR and the lower burden of proof for the PGR process in comparison to patent litigation makes PGR an attractive new tool for generic drug manufacturers. Furthermore, generic drug manufacturers can effectively avoid estoppel under a counterclaim exception for PGR. The primary constraint on PGR, with respect to pharmaceutical litigation, is that patents must be challenged under PGR within nine months of their issuance. At that early stage, it could be uncertain if a particular pharmaceutical patent is valuable and worth challenging, as the compounds and treatment methods described in the patent may only be in the early stages of clinical trials.
The Post Grant Review Process
PGR is a process where a third party can challenge patent claims within nine months of their issuance using evidence on a broad range of grounds, such as subject matter, novelty, nonobviousness, enablement and written description. 35 USC § 321(b),(c). Continue reading


