Claim Construction Defeats CFAD’s Bid To Invalidate Patent On Controlled Release Compositions of 5-ASA

By J. Jason Williams and J. Patrick Elsevier, Ph.D.

In an October 5, 2016, Final Written Decision, the PTAB denied Coalition For Affordable Drugs II LLC’s (“CFAD’s”) request to invalidate a patent held by Cosmo Technologies Ltd. (“Cosmo”) that covers its commercial product Lialda. Coalition For Affordable Drugs II LLC v. Cosmo Techs. Ltd., IPR 2015-00988 (Paper 55) (Oct. 5, 2016). Specifically, the PTAB found that CFAD’s construction of the term “waxes” was not supported by the weight of the extrinsic evidence and thus the prior art did not disclose the patented composition. The PTAB further found that, even if the prior art disclosed the composition, a person of ordinary skill would not find it obvious to combine the recited references because CFAD did not provide a compelling reason to choose the teachings of the prior art over the many pH-independent alternatives for controlled release known in the field at the time of the invention.

The patent at issue in the proceeding—U.S. Patent No. 6,773,720—is directed to controlled release pharmaceutical compositions containing 5-amino salicylic acid (known as 5-ASA or mesalazine). The ’720 patent claims in part an inner lipophilic matrix comprised of substances “selected from the group consisting of unsaturated and/or hydrogenated fatty acid, salts, esters or amides thereof, fatty acid mono-, di- or triglycerids, waxes, ceramids, and cholesterol derivatives” and an outer hydrophilic matrix consisting of certain named polymer groups. The claimed formulation results in a controlled release of highly concentrated 5-ASA for treatment of ulcerative colitis and Crohn’s Disease.

CFAD argued that two prior art references—U.S. Patent No. 3,965,256 to Leslie and EP App. No. 0 375 063 to Groenendaal—rendered claims 1–4 of the ’720 patent obvious. Leslie disclosed slow release oral compositions in matrix form comprising a combination of a higher aliphatic alcohol, such as cetyl alcohol, and a hydrated hydroxyl-alkyl cellulose. Groenendaal disclosed controlled release formulations of oral compositions through solid dispersion which targeted parts of the intestine. Of importance to the determination, CFAD argued that higher aliphatic alcohols were considered “waxes” and thus met the limitations of the claimed inner lipophilic matrix of the ’720 patent. CFAD did not argue for such a construction, but rather indirectly provided a construction in making its obviousness argument. Cosmos countered that “waxes” were esters and did not include higher aliphatic alcohols.

The PTAB held that the context of the claims—as well as multiple treatises and dictionary definitions—supported Cosmos’ definition. Thus, because the disclosures in Leslie were not waxes, the PTAB found that CFAD could not demonstrate that the Leslie-Groenendaal combination would result in the claimed compositions.

The PTAB further noted that due to “the extraordinary variety of pH-independent controlled-release compositions known at the time” of the invention, CFAD’s argument that one would chose the specific reference in Leslie amounted to “merely throw[ing] metaphorical darts at a board filled with combinatorial prior art possibilities.” In particular, the PTAB noted that a formulator would look at many different factors to choose a controlled-release formulation, and that the large time between the two cited references (1976 and 1990) and the patent application (1999) was further evidence that the claimed combinations were not obvious to try.

The CFAD decision underscores the difficulties in establishing obviousness of formulation patents. Even if the cited references had disclosed combinations including “waxes,” it appears unlikely that CFAD would have convinced the PTAB that the claimed compositions would have been obvious to try over the many other potential combinations and alternatives for effecting controlled release. In this field of art, petitioners must clearly demonstrate that those of ordinary skill would have chosen the path disclosed in the cited prior art above other, viable options without undue experimentation.