Senju Pharm. Co. v. Lupin Ltd.

Addressing the issue of obviousness, the U.S. Court of Appeals for the Federal Circuit adopted a deferential review stance toward the district court’s characterization of several prior art references and ultimately upheld its judgment that the asserted claims were obvious. Senju Pharm. Co. v. Lupin Ltd., Case No. 13-1630 (Fed. Cir., Mar. 20, 2015) (Plager, J.) (Newman, J., dissenting).

The claim at issue in Senju was drawn to a method of increasing corneal permeability to an ophthalmic antibiotic by using disodium edetate (EDTA) at a very low concentration and at a pH lower than that used in the cited prior art.  EDTA is a commonplace excipient in ophthalmic solutions, and at high concentrations EDTA is known to increase corneal permeability to help medicine in eye-drops reach the interior of the eye.  At the district court, the parties’ experts disputed whether several prior art references created an expectation of success or, to the contrary, taught away from using the claimed low concentrations of EDTA. The experts also disagreed over whether the results achieved by Senju with its low-concentration formula were unexpected or consistent with the prior art.  Ultimately, the district court credited Lupin’s expert over Senju’s and found that the patents were obvious as the prior art created an expectation of success with the low concentration and that the results achieved were consistent with the prior art.

At the Federal Circuit, the majority and dissent both reviewed the teachings of the various prior art references and reached opposite conclusions.  The majority, casting its decision as deference to the district court’s credibility determination as between the parties’ experts, upheld the judgment.

Judge Newman (who has a background in chemistry), in dissent, re-analyzed obviousness de novo.  She re-examined the prior art references, measured the consistency of the experts’ arguments with those references, and concluded that the disputed claim was not obvious based on what she viewed as a teaching away by the prior art and significant unexpected results at the claimed concentration.

Practice Note:  Practitioners who seek a review of a district court’s fact findings are advised to clearly highlight the alleged clear error(s) and forthrightly request a review of fact finding based on the clear-error standard.