In the spirit of “if at first you don’t succeed, try, try again,” the Coalition for Affordable Drugs (CFAD) challenged a fourth Orange Book-listed patent relating to VIVOMO®, Horizon Pharma’s naproxen/ esomeprazole product. While denying CFAD’s previous three petitions, the PTAB instituted inter partes review for U.S. Patent No. 8,945,621. Despite CFAD’s success at the institute phase, the PTAB ultimately determined in its Final Written Decision that the Petitioner did not meet its burden in proving the unpatentability of the challenged claims.

The ‘621 patent is directed to methods of reducing the incidence of NSAID-associated gastric ulcers in patients taking low dose aspirin (LDA), comprising administering a unit dose form of immediate-release esomeprazole and delayed-release naproxen. All of the claims included the feature: “wherein administration of the unit dose form is more effective at reducing the incidence of the NSAID-associated ulcers in patients taking LDA than in patients not taking LDA who are administered the unit dose form.” Petitioner alleged that the claims were obvious over in view of a reference considered alone or in combination with various secondary references. The PTAB agreed that the cited references suggested many of the features recited in the claims, but determined that Petitioner failed to establish that the references suggested the above-recited “wherein” feature, the subject matter of which was also considered to be a surprising and unexpected result.

Notably, the PTAB disregarded one of Petitioner’s key arguments because the underlying analysis was not fully developed in the petitioner’s initial submissions. Petitioner submitted an expert declaration asserting that the “wherein” clause results were not unexpected in view of the art. Yet neither the petition nor the declaration adequately explained the basis for the expert’s analysis. Petitioner argued that the required analysis was provided in an appendix to the expert declaration. The petition, however, “not only failed to quote [the expert’s] analysis or any part of Appendix B, it did not even allude to it.” The relevant paragraph of the expert declaration also did not reference the appendix. According to the Board, the petition did not contain the required detailed explanation of the significance of the evidence.

Interestingly, the Board had highlighted the deficiencies in the petition and supporting expert declaration in its Institution Decision. Instead of denying institution, however, the Board directed the parties to address two issues at trial: whether the “wherein” clause is entitled to patentable weight, and whether the alleged unexpected results were sufficient to overcome a showing of obviousness. In its final written decision, the PTAB noted that that Petitioner failed to establish that the cited art teaches or suggests the “wherein” clause. The PTAB did not reach the question as to when such a clause is entitled to patentable weight.

Regarding unexpected results, the Patent Owner argued that it was surprising that administration of the unit dose form was more effective at reducing NSAID-associated ulcers in patients taking LDA than in patients not taking LDA. Patients taking both NSAIDs and LDA are at increased risk for developing ulcers. It was, therefore, counterintuitive that the treatment was more effective in patients taking both NSAIDs and LDA. The Board noted that “differences in degree” of a known and expected property are not as persuasive in rebutting obviousness as “differences in kind.” Here, the “surprising result – the opposite of what the ordinary artisan would have expected – represents a difference in kind, rather than degree” (emphasis added).

A previous post summarized CFAD’s success rate at the PTAB. As of this posting, 33 institution decisions have been issued based on CFAD petitions. Fifteen of the petitions were denied and 18 petitions were granted, for an institution rate of roughly 55% (up from 41% in 2015). Of the 13 final written decisions, challenged claims were held to be unpatentable in nine instances (about 70%), whereas all claims survived in four cases (about 30%). CFAD’s institution success rate is lower than trial institution rates for biotech IPRs as a whole (62% as of January 31, 2017). Once trial is instituted, Patent Owners seem to have a similar level of success against CFAD challenges compared to biotech IPRs generally (claims found patentable by PTAB in 33% of biotech final written decisions as of January 31, 2017).