by Marin Cionca and Iris Kim 

        In June 2015, Amgen challenged two patents (US Patent Nos. 8,916,157 and 8,916,158) owned by AbbVie Biotechnology Ltd., related to the drug Humira. The challenge was on the grounds that the reformulations of the biologic described in these patents are not significantly different from that of the prior art. The Patent Trial and Appeal Board (PTAB or The Board) has denied both of Amgen’s requests for inter partes review, in Amgen Inc. v. AbbVie Biotechnology Ltd. case numbers IPR2015-01514 and IPR2015-01517.

AbbVie asserted to the Board that preparing stable liquid aqueous formulations of antibodies at the recited concentrations may lead to unpredictable results. A claim is unpatentable as being obvious if “the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made” (35 U.S.C. 103(a)) to one of ordinary skill in the art. Absolute predictability is not a requirement for obviousness, but “some articulated reasoning with rational underpinning to support the legal conclusion of obviousness” should be present (KSR, 550 U.S. at 418 (quoting In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006)).

In case IPR2015-01517, Amgen had submitted an argument that an article, Wang, provided guidance for formulating stable liquid aqueous antibodies at the concentration recited in the patents. However, AbbVie asserted that the Wang article demonstrates unpredictability in this art of formulating proteins as well, stating “[v]ery often, proteins have to be evaluated individually and stabilized on a trial-and-error basis.” “Although the Wang article indeed provides general guidance, the Wang article also underscores the unpredictability of the undertaking” (PTAB, IPR2015-01517).

Further examples of references that provide general guidance were provided. Amgen argued using Salfeld and Heavnerm stating that “because both focus on anti-TNF alpha antibodies, both focus on IgG antibodies, and both teach how to formulate these antibodies” a skilled artisan “would have had reason to combine Salfeld and Heavner” (PTAB, IPR2015-01517). AbbVie’s response was that Salfeld provides guidance “merely as a general approach” and Heavner only provides “bulk recitations” and “offers no guidance at all on how to actually select from this massive number of possible combinations” (PTAB, IPR2015-01517).

Given these arguments, the Board found that Amgen was not persuasive in their argument that a “skilled person would have had a reasonable expectation of success in applying the formulations commercially available and taught in the literature to D2E7,” D2E7 being the antibody described in the ‘158 patent (PTAB, IPR2015-01517). The Board concluded “that Amgen has not established a reasonable likelihood of prevailing with respect to its challenge,” (PTAB, IPR2015-01517). Similar arguments were presented in case IPR2015-01514, and both requests for inter partes review were denied in January 2016, demonstrating that, even with guidance, unpredictability may still be a factor in certain fields.