Summary
The United States Court of Appeals for the Federal Circuit affirmed the Patent Trial and Appeal Board's rejection of Xencor's patent application claims for lacking sufficient written description. The court held that the limiting preamble of a Jepson claim requires written description support, and that the phrase "treating a patient" in the method claim's preamble is a limiting limitation. Substantial evidence supported the finding that the specification failed to demonstrate possession of treating patients with the claimed anti-C5 antibodies.
Topics
Practice areas
Questions Presented
- Whether the limiting preamble of a Jepson claim requires a written description under 35 U.S.C. §112.
- Whether the phrase “treating a patient” in the preamble of claim 9 is a limiting limitation that requires written description.
- Whether the Board’s factual findings that Xencor lacked adequate written description are supported by substantial evidence.
Holdings
- The limiting preamble of a Jepson claim must be supported with sufficient written description, and the patentee’s burden of written description extends to the limiting preamble.
- The phrase “treating a patient” in the preamble of claim 9 is a limiting limitation that must be supported by written description.
- Substantial evidence supports the Board’s finding that Xencor failed to provide adequate written description for both the Jepson claim preamble and the claim‑9 preamble.
Factual background
Xencor’s patent application claimed anti‑C5 antibodies, including the monoclonal antibody 5G1.1, modified to have longer serum half‑life. The application disclosed limited data and did not describe specific diseases or conditions for treating patients with the claimed antibodies.
Procedural history
The Board issued an initial decision on Jan. 10, 2023 rejecting the claims for lack of written description. After rehearing, the Board again rejected the claims. The ARP issued its decision on May 21, 2024 affirming the Board’s findings. Xencor appealed the ARP decision to the Federal Circuit.