Well-Known Genus, Novel Method: A Post-Amgen Framework for Written Description & Enablement

Why It Matters

The distinction reshapes how biotech firms protect antibodies, ADCs, and biologics, influencing both patent drafting and enforcement tactics across the life‑science industry.

Key Takeaways

• Teva decision narrows enablement bar for method‑of‑use claims
• Seagen and OssiFi‑Mab risk invalidation of broad genus claims
• Amgen doctrine now applied context‑sensitively
• Portfolio audits should focus on Wands‑factor compliance

Pulse Analysis

The Federal Circuit’s recent rulings illustrate a nuanced evolution of the Amgen written‑description doctrine, a cornerstone of U.S. patent law for biotech inventions. While Amgen Inc. v. Sanofi set a high bar for patents that define a novel genus of compounds, courts now differentiate between claims that treat the genus as the invention and those that merely employ a known genus to achieve a specific therapeutic outcome. Cases such as Seagen Inc. v. Daiichi Sankyo and OssiFi‑Mab LLC v. Amgen reaffirm that broad, functionally defined genus claims can be invalidated when the specification fails to disclose enough embodiments, forcing skilled artisans into trial‑and‑error experimentation.

Conversely, the Teva Pharmaceuticals International GmbH v. Eli Lilly & Co. decision signals relief for method‑of‑use claims. By deeming the isolation of particular embodiments for a targeted treatment a routine exercise, the court effectively lowered the written‑description and enablement thresholds for patents that leverage a well‑known chemical class. This creates a strategic avenue for biotech companies to secure protection for innovative applications of existing molecular scaffolds without the exhaustive disclosure demanded for new genera, thereby accelerating time‑to‑patent and reducing litigation exposure.

For IP counsel, the practical implications are immediate. Portfolios heavy with composition‑of‑matter claims should undergo rigorous audits against the Wands factors to ensure sufficient disclosure, while drafting new applications may benefit from framing inventions as novel therapeutic methods using known genera. This dual approach balances the need for robust protection with the realities of regulatory approval and commercial exploitation, positioning firms to navigate an increasingly sophisticated patent landscape.