On January 3, 2021, a panel of Federal Circuit Judges split on the question of whether a claim reciting a dosing regimen of a drug “absent an immediately preceding loading dose regimen” was properly supported by the specification of a patent. The majority of the panel felt that a person of ordinary skill reading the disclosure would understand that a “loading dose” regimen was not part of the claimed invention even though the specification did not discuss a loading dose regimen.

The losing party then filed for a petition for a panel rehearing. But Circuit Judge O’Malley, who joined Circuit Judge Linn in the majority, retired after the decision. Circuit Judge Hughes then joined the original dissenter, Chief Judge Moore, to grant the petition for panel rehearing and hold that the failure to mention and exclude a loading dose regimen fatal to the claims.

Considering that petitions for panel rehearing are rarely granted, the Federal Circuit’s process for replacing a retired judge from the majority in a case involving a dissent could raise questions regarding whether the original decision’s rationale was properly respected, and at least the appearance that procedure and external events, rather than law, affected the outcome.