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IP: Is there a shelf life for invalidating prior art?

The Federal Circuit finds older prior art less reliable in attempting to show obviousness

In a somewhat rare reversal of an obviousness decision by the Board of Patent Appeals and Interferences, the Federal Circuit’s recent decision in Leo Pharmaceutical Products, Ltd. v. Rea provides important guidance in navigating the post-KSR landscape. In applying a common-sense evaluation of the facts, the court placed great emphasis on the passage of time between the asserted prior art and the claimed invention, which it found “sp[oke] volumes” against obviousness. The court also highlighted the importance of considering whether the prior art disclosed the problem solved by the inventors, and reminded litigants that objective indicia of nonobviousness must be more than a mere “afterthought” in an obviousness analysis.

The ’013 patent-at-issue claimed “storage stable” compositions for the treatment of skin conditions containing, inter alia, vitamin D and a corticosteroid. The prior art recognized the efficacy of vitamin D/corticosteroid treatment but did not disclose any storage-stable combinations of these two ingredients. Instead, the prior art largely recommended separate administration of these drugs, which led to patient-compliance issues.

At the outset, the Federal Circuit noted that the Board had ignored a critical fact in its obviousness analysis: The stability issue associated with vitamin D/corticosteroid formulations had gone unrecognized until the inventors solved this problem through the patented formulation. In the absence of a known problem, one of ordinary skill in the art would not have been motivated to combine the asserted prior art so as to arrive at a storage-stable combination treatment, particularly given that certain prior-art articles taught away from mixing topical vitamin D formulations with other drugs. The court further found that, despite recognizing the efficacy of a combination treatment, the prior art provided only “broad and general disclosures” as to possible combination formulations. Consequently, without enough clues as to promising combinations, the skilled artisan “could have spent years experimenting without success.”

Overarching this analysis was the Federal Circuit’s repeated reference to the decade or two that passed between the asserted prior art and the development of the claimed invention. In directly addressing the reach of the Supreme Court’s KSR decision, the court held that “The elapsed time between the prior art and the ’013 patent’s filing date evinces that the . . . claimed invention was not obvious to try.” Finally, the court emphasized the importance of objective indicia, noting that they constitute “‘independent evidence of nonobviousness’” that must be considered as “part of the whole obviousness analysis” whenever an issued patent is challenged. The Federal Circuit found that the presented objective indicia — including unexpected stability and the fulfillment of a “long felt but unsolved need” for an FDA-approved vitamin D/corticosteroid combination product — were crucial in enabling the court to “avert the trap of hindsight.” Once again emphasizing the importance of critically evaluating the credibility of vintage prior art, the court also relied upon the “length of the intervening time between the publication dates of the prior art and the claimed invention” as another objective indicium supporting nonobviousness.

Leo Pharmaceutical reminds litigants of the importance of remaining focused on a practical evaluation of the relevant facts and avoiding the all-too-common trap of combining prior art through general, hindsight-driven “obvious to try” approaches. Importantly, the decision also confirms that a patentee can rely upon the passage of time between the asserted prior art and the claimed invention in arguing both lack of motivation and objective indicia of nonobviousness. Although the particular delay at issue in Leo Pharmaceutical was fairly long, the general principle underlying court’s analysis provides a potential additional weapon to wield in attempting to ward off obviousness attacks.

Contributing Author

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Eric Dittmann

Eric W. Dittmann is a partner in the Litigation practice of Paul Hastings. Mr. Dittmann focuses his practice on intellectual-property litigation and client counseling in...

Additional Contributors: Elina Saviharju

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