Federal Circuit Clarifies Written Description, Enablement for Pharma Method-of-Use Patents
In-house IP and pharma/biotech counsel must update patent drafting and litigation strategies to align with binding Federal Circuit precedent on validity requirements for method-of-use claims covering known compound genera.
The article analyzes two 2025–2026 Federal Circuit decisions clarifying 35 U.S.C. § 112 written description and enablement requirements for pharmaceutical method-of-use claims covering known compound genera. In Teva v. Eli Lilly, the court reversed a JMOL invalidity ruling in a posture-sensitive decision, finding claims for humanized anti-CGRP antibodies to treat headache satisfied § 112 because the antibodies were well-known, humanization was routine, the specification disclosed the therapeutic use, and the jury’s factual findings were supported by substantial evidence. In In re Xencor, the court affirmed a written description rejection for claims covering anti-C5 antibodies with specific Fc substitutions for patient treatment, holding the specification lacked support for the full scope of the claimed treatment method. In-house counsel should review existing method-of-use patent portfolios for compliance with these precedents, and adjust future claim drafting to clearly tie claimed compound genera to their specific disclosed therapeutic uses.