Patentability of polymorphic compounds: an analysis based on recent EPO decisions

The present study analyzes how the European Patent Office (EPO) Boards of Appeal evaluate the patentability of polymorphic chemical compounds, with a focus on novelty (Article 54 EPC) and inventive step (Article 56 EPC). The paper utilizes leading and recent EPO decisions-including T 777/08, T 1684/16, T 1326/18, T 672/21, T 1994/22, T 2086/21, and T 2157/21-to synthesize the evidentiary demands and propose a structured account of when polymorph claims can be patentable. Polymorph claims are typically patentable when a specific solid form is novel and delivers an unexpected technical advantage (often understood as a valuable balance of properties) that can be credibly attributed to the form as claimed.