Lead Compound Analysis Not Required Where The Prior Art References Expressly Suggest The Proposed Modification

When assessing obviousness of a chemical compound, Federal Circuit caselaw generally follows a two-part inquiry referred to as the "lead compound" analysis. However, in Cytiva BioProcess R&D AB v. JSR Corp.¹, the U.S. Court of Appeals for the Federal Circuit ("Federal Circuit" or "CAFC") explained the flexibility in the use of lead compound analyses when determining patentability or validity of claimed chemical compounds under 35 U.S.C. § 103. While commonly used, the lead compound analysis is not, as a strict rule, always required. Rather, because the Supreme Court emphasized flexibility over rigid and formalistic rules in considering obviousness in KSR², such flexibility should also be applied to obviousness assessment of new chemical compounds.