Determining the amount of disclosure sufficient to satisfy the written description and enablement requirements of 35 U.S.C. § 112(a) can be difficult, especially in the fields of biotechnology, pharmaceuticals, and other unpredictable arts. In a recent precedential decision from the Federal Circuit (Teva Pharms. Int’l GmbH v. Eli Lilly & Co.), the appellate court identified circumstances where disclosing a single species satisfied the written description and enablement requirements for a genus of humanized antibodies in a patent claim directed toward a method of treatment for headaches.
Background
Teva Pharmaceuticals owns three patents (the “headache patents”) directed to methods for treating headaches in humans using mouse antibodies that have been converted into a form the human immune system will not reject (a process called humanization). The specifications of the headache patents observed that the specific mouse antibodies, and how to make them, were “known in the art” and cited examples of mouse antibodies being sold. The specifications also disclosed prior-art methods of humanization but disclosed just one humanized antibody (“G1”) that was the active ingredient in Teva’s product.
Teva sued Eli Lilly & Co in the U.S. District Court for the District of Massachusetts for infringement of the headache patents, and a jury found Lilly willfully infringed the headache patents and awarded Teva damages. However, the district court overturned the jury’s verdict concluding that, as a matter of law, the asserted headache patent claims were invalid for failing to satisfy the written description and enablement requirements. Teva appealed to the Federal Circuit.
The Federal Circuit’s Analysis
The Federal Circuit addressed the written description requirement first, acknowledging that “what it takes to satisfy that requirement varies depending on the context, including the nature and scope of the claims.” Adequate written description to support claims involving a genus require disclosure of “a representative number of species” within the genus, but there are no bright-line rules governing how many species constitute a “representative number.” Lilly argued that the disclosure of only one species, G1, of the claimed genus of humanized antibodies in the headache patents could not be sufficient disclosure.
The court rejected Lilly’s argument, highlighting that the claim was directed at using the genus to treat headaches, instead of claiming the genus itself. In this context, disclosure of a single species satisfied the written description requirement where a claim pertains to a well-known genus that is not, itself, the invention, and the specification disclosed (1) examples of the mouse antibodies were well-known, (2) the methods of making those mouse antibodies were well-known, and (3) the process for humanizing those mouse antibodies to species under the claimed genus was routine.
The court next addressed the enablement requirement of 35 U.S.C. § 112: A patent specification “must teach those skilled in the art how to make and use the full scope of the claimed invention without undue experimentation.” Lilly argued that only disclosing one species out of a very large number of mouse antibodies that could fit in the genus, without disclosing how to determine in advance which ones would have the effect to treat a headache, required undue experimentation by others.
The court again rejected Lilly’s argument explaining that (1) the mouse antibodies and methods of making them were already well known, (2) the humanizing process was routine, (3) the species themselves were not claimed, and (4) all species of the genus work in the claimed method. Hence, the Federal Circuit deemed an undertaking to find or make all species to determine the scope of the genus to not be undue experimentation, but rather “extra credit.” The screening process argued by Lilly was not necessary in light of the information disclosed in the specification. The Federal Circuit remanded the case to the district court for further proceedings.
Takeaways
- Greater disclosure is required when the genus itself is the invention. When analyzing the adequacy of a written description for a patent claim dealing with a genus, practitioners should distinguish whether the invention is the genus itself or the genus is simply used as a part of a different invention.
- Undue experimentation is not required to determine the bounds of a claimed genus where all precursors and processes for converting the precursors to species are well known in the art, if all species of the genus provide the claimed function of the genus.
