Summary Judgment of Invalidity of OssiFi-Mab’s Patents Asserted Against Amgen’s Evenity®

Why It Matters

The ruling removes a major patent barrier for Amgen, preserving market access to Evenity® and signals stricter enforcement of § 112 standards for biotech inventions, influencing future patent drafting and litigation strategies.

Key Takeaways

• Court invalidated three OMAB patents for lack of description
• Claims covered broad antibody genus without sufficient sequences
• Enablement failed due to trial‑and‑error screening requirement
• Evenity® generated $1.6 B U.S. sales in 2025
• Decision strengthens § 112 written description standards for biotech

Pulse Analysis

The Massachusetts district court’s decision pivots on the written‑description requirement, a cornerstone of 35 U.S.C. § 112. By demanding that a patent disclose a representative number of species or common structural features, the court rejected OssiFi‑Mab’s reliance on functional language alone. The analysis highlighted that the specification listed only a handful of anti‑sclerostin antibodies—none suitable for human therapy—and omitted sequence data, rendering the claimed genus indefinable to one of ordinary skill. This strict interpretation aligns with recent Supreme Court precedent emphasizing that broader claim scope mandates commensurate disclosure.

For Amgen, the judgment clears a legal obstacle to Evenity®, a high‑revenue romosozumab product that generated $1.6 billion in U.S. sales last year. By invalidating the patents, Amgen avoids potential royalty payments or injunctions that could erode its market share in the osteoporosis segment. The outcome also illustrates how robust defensive litigation can protect blockbuster drugs, reinforcing the importance of thorough prior‑art searches and proactive patent portfolio management for pharmaceutical firms.

Industry‑wide, the case serves as a cautionary tale for biotech innovators drafting antibody‑related patents. The court’s application of the *Wands* enablement factors—highlighting the impracticality of trial‑and‑error screening for tens of thousands of variants—signals that functional claims must be buttressed by concrete examples or detailed structural disclosures. Companies are likely to invest more in early‑stage data generation and detailed sequence reporting to satisfy § 112, potentially reshaping the landscape of biotech patent prosecution and reducing the prevalence of overly broad, vulnerable claims.