We have previously reported on IPR2016-01542, in which Apotex challenged US Patent No. 8,952,138, directed to a protein refolding process. On February 15, 2018, the PTAB issued a final written decision finding claims 1-17 and 19-24 of the ’138 patent invalid. On March 16, 2018, Apotex requested a rehearing relating to the PTAB’s interpretation of “non-aerobic conditions” and the decision that Apotex had not shown claim 18 was unpatentable. The PTAB ordered a round of additional briefing, including an opposition to the rehearing request, and briefs from both sides explaining the meaning of the term “non-aerobic conditions.” On May 20, 2019, the PTAB denied the request for rehearing because Apotex failed to raise its argument regarding the proper definition of “non-aerobic conditions” in its Petition.
However, despite denying the request for rehearing, the Board conceded that it had “overlooked” the express definition given to the term “non-aerobic conditions” given in the specification. The ’138 specification defines the term “non-aerobic conditions” as “any reaction or incubation condition that is performed without intentional aeration of the mixture by mechanical or chemical means,” and both parties, in supplemental briefing, agreed that this definition should control. Based on the parties’ undisputed construction of “non-aerobic conditions” as the definition set forth in the ’138 patent, the PTAB sua sponte decided to modify its final written decision to find claim 18 unpatentable as obvious. Claim 18 depends from claim 1 (earlier found to be invalid as obvious) and additionally recites that incubation is performed under “non-aerobic conditions.” Thus, the PTAB found Claim 18 only required that any reaction or incubation condition “be performed without the intentional aeration of the mixture by mechanical or chemical means.” Since two prior art references (a 1996 journal article and a previous U.S. patent application) both described aeration of a chemical mixture that was not intentional, they “satisf[ied] the requirement for incubation performed under ‘non-aerobic’ conditions.” Thus, the Board altered its previous decision to conclude that Apotex sufficiently demonstrated that claim 18 was unpatentable as obvious.