Of all the tools available to Examiners when rejecting claims for obviousness, perhaps none are stronger or more frequently misapplied than the doctrines of routine optimization and result effective variable. The Federal Circuit’s recent decision in Pfizer Inc. v. Sanofi Pasteur Inc. (Fed Cir 2024) (“Pfizer v. Sanofi”), in an IPR between two vaccine heavyweights, provides an excellent framework for a better understanding of the doctrines.
During examination, we are often confronted with the argument that "where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." This proposition was first articulated in 1955 in In re Aller (CCPA 1955), and it figured prominently in Pfizer v. Sanofi.
Pfizer v. Sanofi involved claims directed toward the molecular weight of a Streptococcus pneumoniae serotype 22F glycoconjugate. Disputed claim 1 recited:
An immunogenic composition comprising a Streptococcus pneumoniae serotype 22F glycoconjugate, wherein the glycoconjugate has a molecular weight of between 1000 kDa and 12,500 kDa and comprises an isolated capsular polysaccharide from S. pneumoniae serotype 22F and a carrier protein, and wherein a ratio (w/w) of the polysaccharide to the carrier protein is between 0.4 and 2.
During an IPR brought by Sanofi, the Board concluded that the claim was invalid for obviousness because Streptococcus pneumoniae serotype 22F was in the prior art and, while the prior art did not disclose a suitable molecular weight for the 22F serotype, (i) the molecular weight range in claim 1 overlapped a range reported in the prior art for different Streptococcus pneumoniae serotypes (1000-12,500 kDa vs. 1303-9573 kDa), (ii) molecular weight was known to be a “result-effective variable associated with improved stability of conjugates and good immune response,” and (ii) “the methods and conditions for creating the glycoconjugates of the invention [at different molecular weights] were generally recognized as routine.”
The Board essentially used the doctrine of routine optimization to disregard Pfizer’s evidence of unexpected results. Pfizer had presented evidence that a suitable molecular weight for the 22F subtype required "case-by-case experimentation" and "individualized design and testing,” but the Board rejected the evidence because, according to the Board, the molecular weight would have been arrived at via routine optimization.
Pfizer could have overcome the routine optimization argument with more proof that (1) finding an optimum working range would not have been a routine endeavor, or (2) “the given parameter [molecular weight] was not recognized as result-effective”. Alternatively, it could have produced evidence of criticality under Genentech, Inc. v. Hospira, Inc. (Fed. Cir. 2020). Pfizer presented evidence on the first two points but its evidence simply was not strong enough to overcome Sanofi’s opposing evidence.
Pfizer argued on appeal that this framework violated Federal Circuit routine optimization precedent, but the Federal Circuit rejected the argument because it relied “on the faulty premise that where optimization requires case-specific considerations, then the results must be unexpected [and therefore nonobvious].” According to the Federal Circuit, the very nature of a routine optimization rejection allows for some case-specific considerations, as long as the totality of the evidence shows that “the general conditions of a claim are disclosed in the prior art,” and the “optimum or workable ranges [could be discovered] by routine experimentation."
