Maintaining the Balance: An Empirical Study on Inter Partes Review Outcomes of Orange Book Patents and its Effect on Hatch-Waxman Litigation

Abstract

The Hatch-Waxman Act intended to strike a delicate balance between encouraging pioneer drug innovation and promoting market entry of affordable generic versions of pioneer drugs by providing a streamlined pathway to challenge validity of Orange Book patents in federal district courts. In 2012, the America Invents Act introduced Inter Partes Review (IPR) proceedings which provide a faster, cheaper pathway to challenge Orange Book patents than Hatch-Waxman district court litigation. IPRs also have a lower evidentiary burden of proof and broader claim construction standard, which should make it easier, in theory, to obtain patent invalidation in IPRs as compared to Hatch-Waxman litigation. This empirical study of all 412 IPRs filed against 230 Orange Book patents between 03/16/2012 and 03/16/2018 shows that both generic manufacturers and patent owners obtain more favorable final decisions in IPRs as compared to their Hatch-Waxman litigation outcomes because the rate of settlement in IPRs is much lower than in Hatch-Waxman litigation. Moreover, generic manufacturers do not appear to be targeting Orange Book patents in IPRs during their drug exclusivity period. Only 2 out of more than 400 IPRs against Orange Book patents were filed by generic petitioners during the patents’ New Chemical Entity exclusivity period. About 90% of the 230 Orange Book patents challenged in IPR proceedings were also challenged in Hatch-Waxman litigation. It is likely that generic manufacturers are not deterred from Hatch-Waxman litigation because of the lucrative 180-day exclusivity period, which gives the first generic filer 180 days to exclusively market their generic version without competition from other generics when the Orange Book drug patent is successfully invalidated in a subsequent district court proceeding. Therefore, IPR proceedings do not appear to be disrupting the delicate balance sought by the Hatch-Waxman Act. Instead, the IPR process has provided generic manufacturers a dual track option for challenging Orange Book patents by initiating Hatch-Waxman litigation in district courts and also pursuing patent invalidity in IPRs before the Patent Trial and Appeal Board, which has reduced rate of settlements resulting in more patents being upheld and invalidated.

Keywords: AIA, IPR, Orange Book Patents, Hatch-Waxman, ANDA

JEL Classification: K23, K41, O31, O32, O34, O38