No Pain Relief at the PTAB: Inherent Obviousness

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.

The Board found the claims to administering these pharmaceutical compositions to be obvious in view of the patent owner’s earlier ‘285 patent.  The prior patent disclosed the same two-drug pharmaceutical compositions, but did not include the dosage schedule or PK/PD profile. Specifically, the Board believed the missing element of twice daily doses (morning and afternoon) to be obvious because the ‘285 patent disclosed twice daily dosing of one drug (naproxen) alone, the long 12-15 hour half-life of naproxen, and the two-drug composition. This determination was based, at least in part, on the benefits for patient compliance and ease of scheduling. The Board next concluded that the ‘285 patent inherently disclosed the claimed PK/PD profile because a skilled artisan would ordinarily expect that administration of the composition via the claimed dosing schedule would result in the claimed PK/PD profile. This determination relied on Federal Circuit precedent holding that the natural results and properties of a prior formulation are inherent.

Lastly, the Board dismissed the objective indicia of nonobviousness as unpersuasive because the Board found this indicia was missing the required nexus to the novel PK/PD profile of the claims. Overall, the Board held that the claims to administering a previously disclosed two-drug pharmaceutical composition twice daily with a recited PK/PD profile were inherent and obvious in view of the ‘285 patent’s disclosure of the claimed composition and twice-daily administration of one drug.


Be aware that even if the prior art does not expressly disclose a claim element, inherency can be relied on to invalidate the claim as obvious. For example, inherency may be applied to supply claimed properties that are not expressly disclosed, such as dosing schedules and the PK/PD profiles. Accordingly, it may be difficult to claim methods that incorporate such properties, especially if the result would ordinarily be expected. However, patentees still should be able to obtain claims to methods reciting novel and surprising properties.