Even when certain elements in a claimed method are not expressly disclosed in the prior art, the claim can still be held obvious if the missing elements are supplied in the form of an inherent property. In the pharmaceutical context, the PTAB decision in Dr. Reddy's Laboratories, Inc. v. Pozen Inc. (IPR2018-00894; PTAB 2019) illustrates the continuing difficulty in claiming methods of administering a known two-drug pharmaceutical composition with an expected pharmacokinetic and pharmacodynamic (PK/PD) profile. The patent at issue covers methods of administering morning and afternoon daily doses of the arthritis pain reliever Vimovo®. Specifically, the claims recite particular PK/PD profiles, including the highest plasma concentration of the drug following administration, drug bioavailability, and amount of drug exposure for compositions of naproxen (a nonsteroidal anti-inflammatory drug “NSAID”) and esomeprazole (a proton pump inhibitor (PPI)). Esomeprazole is used in conjunction with naproxen to reduce the risk of gastrointestinal injury from naproxen by raising the gastrointestinal tract pH.
Prodrugs are inactive compounds designed to be converted into pharmaceutically active metabolites following delivery to a patient. Prodrugs have important pharmacokinetic advantages over traditional compounds, and a recent PTAB decision, Lupin Limited v. Vertex Pharmaceuticals Inc. (IPR2016-00558), illustrates how prodrugs can possess patent advantages as well. In its analysis of obviousness, the PTAB focuses on unpredictable results and whether a person of ordinary skill in the art has a reasonable expectation of success in view of the available art, as outlined in Procter & Gamble Co. v. Teva Pharm. USA, Inc., 566 F.3d 989 (Fed. Cir. 2009), frequently applied in pharmaceutical cases.