The US Court of Appeals for the Federal Circuit affirmed the Patent Trial & Appeal Board’s determination that 79 challenged composition claims across three related patents were unpatentable but reversed the Board’s determination that four challenged process claims were not unpatentable. Cytiva Bioprocess R&D v. JSR Corp., et al., Case Nos. 23-2074; -2075; -2191; -2192; -2193; -2194; -2239; -2252; -2253; -2255 (Fed. Cir. Dec. 4, 2024) (Prost, Taranto, Hughes, JJ.)

The patents in question pertain to chromatography matrices used in affinity chromatography for isolating antibodies. Their primary focus was on the G29A mutation in SPA IgG binding domains, which enhances stability in alkaline environments. The Board upheld the patentability of the process claims while invalidating the composition claims. Cytiva appealed, arguing that the Board erred in its lead compound analysis. JSR cross-appealed on the Board’s finding that the challenged process claim were not unpatentable.

The Federal Circuit disagreed with Cytiva’s argument that a lead compound analysis was necessary. A lead compound analysis is an obviousness framework that involves a two-part inquiry: whether a skilled person in the art would have selected the compound as a starting point for research, and whether the prior art would have motivated the skilled person to modify the compound into the claimed invention. The Federal Circuit noted that lead compound analyses are not always required in chemical patent cases where the prior art references expressly suggest the proposed modification, which was the case here. The Court also explained that even though a lead compound analysis was used here, in this case the claimed compounds could all be lead compounds, and the prior art expressly suggested the G29A modification of the claimed compound.

The Federal Circuit also addressed whether a claim limitation that merely recites an inherent property of an otherwise obvious combination requires additional analysis to demonstrate that a person of ordinary skill in the art would have a reasonable expectation of success. The Court found that additional analysis was unnecessary because “the sole disputed limitation was an inherent property of the claimed composition already determined to be obvious.” The Court found that the Fab binding property of the chromatography matrices was inherent and thus did not require a separate reasonable expectation of success analysis.

As for the process claims that the Board found not unpatentable, the Federal Circuit determined that the composition and process claims were “nearly identical and contain[ed] no substantive distinction relevant to th[e] appeal.” Therefore, the Court held that the Board erred in separating the composition and process claims and found “no basis for treating the claims differently.” The Federal Circuit reversed the Board’s “not unpatentable” determination on those claims and held all challenged patent claims obvious and therefore unpatentable.

This article was authored by Hannah Hurley