The recent Federal Circuit Court of Appeals decision in Leo Pharmaceutical Products, Ltd. v. Rea (Appeal No. 2012-1530, 2013 U.S. App. LEXIS 16610, decided Aug. 12, 2013) provides patent applicants and owners with some valuable ammunition in rebutting “obvious to try” based obviousness assertions against patent claims under 35 U.S.C. §103, both during patent prosecution and patent invalidity proceedings.
In Leo, an appeal from an inter partes reexamination proceeding at the U.S. Patent and Trademark Office, the court reversed the Board of Patent Appeals and Interferences’ holding of obviousness of a pharmaceutical composition on the basis that a person of ordinary skill in the art would not have been motivated to try, let alone make, the claimed invention (*14).
The court found that a claimed storage stable pharmaceutical composition comprising (1) at least one vitamin D analogue, (2) at least one corticosteroid, and (3) at least one solvent selected from a specified group, was “not simply a combination of elements found in the prior art” (*11) (three prior art references relied upon by the Board in finding the compositions obvious), but, rather, the inventors recognized and solved a problem with the storage stability of certain formulations — a problem that the prior art did not recognize and a problem that was not solved for more than a decade:
“The problem was not known, the possible approaches to solving the problem were not known or finite, and the solution was not predictable. Therefore, the claimed invention would not have been obvious to try to one of ordinary skill in the art. Indeed ordinary artisans would not have thought to try at all because they would not have recognized the problem.” (*17-18).
The court observed that though two of the three prior art references disclosed combinations of (1) vitamin D and (2) a corticosteroid, with a different solvent than claimed, those references did not recognize or solve the storage stability problems associated with their combinations. On the other hand, while the third prior art reference disclosed (2) a corticosteroid and (3) the claimed solvent, combining this combination with (1) vitamin D is “only straightforward in hindsight” (*14). The court observed that this third reference was available for 22 years before the patent filing, yet there was no evidence that anyone sought to improve its disclosed composition.
Though the board’s decision found that, based on the prior art’s disclosure of additives and categories of formulations, an artisan would have been able to make choices about what ingredients to include, and which to exclude, in formulating a composition with a vitamin D analog and steroid, the court found, to the contrary, “the breadth of these choices and the numerous combinations indicate that these disclosures would not have rendered the claimed invention obvious to try” (*16), and held:
“Where the prior art, at best gives only general guidance as to the particular form of the claimed invention or how to achieve it, relying on an obvious-to-try theory to support an obviousness finding is impermissible…. Further, KSR did not create a presumption that all experimentation in fields where there is already a background of useful knowledge is ‘obvious to try,’ without considering the nature of the science or technology.” (internal citations and quotation marks omitted).
Interestingly, the court also found the age of the cited prior art references, which were published decades before the patent’s filing date, and the elapsed time between the prior art and the patent’s filing date, to be evidence of the nonobviousness of the claimed combination, and particularly that the invention was not obvious to try:
“If these discoveries and advances were routine and relatively easy, the record would undoubtedly have shown that some ordinary artisan would have achieved this invention within months of Dikstein or Serup. Instead this invention does not appear for more than a decade.” (*13).
This decision provides important and helpful precedent for responding to “obvious to try” based patent claim rejections or invalidity assertions, not only in the chemical field but other technology fields as well, where the claimed invention is based on both the discovery and solution of a problem and/or where a significant period of time has elapsed between the date of the asserted prior art and the claimed invention.