By Jonathan B. (J.B.) Fitzgerald, Ph.D., J.D., and Jeffrey D. Morton, Ph.D., J.D., Snell & Wilmer L.L.P.
On Aug. 26, 2021, the Federal Circuit reversed a jury verdict for Juno Therapeutics and the Sloan Kettering Institute for Cancer Research (hereinafter referred to as Juno) in the case Juno Therapeutics, Inc. v. Kite Pharma, Inc., No. 20-1758 (Fed. Cir. 2021). This ruling wiped out a $1.2 billion judgment for Juno in the lower court by invalidating claims of the 7,446,190 Patent (the ‘190 Patent) that were directed to the functional properties of biological compounds that could be used as therapies.
The Juno v. Kite case shows the difficulty inventors face when attempting to obtain patent protection for biological compositions by claiming the compositions’ functional properties. After providing a brief summary of the Juno v. Kite case, this article discusses how Juno failed to show that it possessed its functionally claimed biological compounds and the challenges of satisfying the written description requirement for biological compounds when the compounds are claimed according to their functional properties.
Summary Of The Juno V. Kite Case
The ‘190 Patent claims cover a nucleic acid polymer that encodes a chimeric T cell receptor that can be used in therapeutics. One of the elements of the chimeric T cell receptors is a binding element, which is a single-chain variable fragment (scFv). A scFv is a fusion protein that contains regions of antibodies that are capable of binding to therapeutic targets. Thus, the chimeric T cell receptor encoded on the polymer can carry out its therapeutic function, in part, because the scFvs are capable of binding to critical therapeutic targets.
Notably, the binding element, or the scFv, was claimed according to its function of being capable of binding to targets of clinical interest. Specifically, the relevant portion of the claim recited “a binding element that specifically interacts with a selected target.” This claiming strategy is in contrast to claiming the binding element according to its specific structural features, such as its amino acid sequence.
Kite Pharma developed a therapeutic composition that contains an scFv, a molecule that is often targeted in cancer therapies. Thus, Kite’s therapeutic composition was purportedly covered by the claims in the ‘190 Patent, in that the composition contained an scFv binding element capable of binding a selected clinical target (i.e., CD19).
Juno sued Kite, alleging that Kite’s scFv that targeted CD19 infringed the ‘190 Patent. Kite defended by asserting that the claims in the ‘190 Patent were invalid for failing to meet the written description requirement, mandated under 35 U.S.C. § 112. In general, to meet the standard of the written description requirement under § 112, the patent description must show that the inventor(s) had possession of the full scope of the claimed invention at the time of filing.
At the U.S. District Court of the Central District of California, a nine-member jury unanimously held that the claims met the written description requirement. Further, the District Court found that Kite had willfully infringed the ‘190 Patent with its scFv compound that targets CD19. A final judgment was issued against Kite totaling $1.2 billion in damages.
Kite appealed the case to the Federal Circuit. Because the Federal Circuit found that the jury verdict regarding written description was not supported by substantial evidence, it reversed the District Court’s decision. According to the Federal Circuit, the patent disclosure failed to provide sufficient disclosure to cover any scFv binding element capable of interacting with any selected clinical target. As a result, the patent disclosure failed to show that the inventors possessed the full scope of the claimed invention at the time of filing. Thus, the Federal Circuit found that claims were invalid for failing to meet the written description requirement and reversed the $1.2 billion judgment against Kite.
Juno Failed To Show That It Possessed Its Functionally Claimed Biological Compounds
The Legal Standard For Meeting The Written Description Requirement For Juno’s Claimed scFvs
In general, the law allows for two alternatives to show possession and, thus, satisfy the written description requirement, of a genus claim. The first alternative is to provide a representative number of species of the genus. The second alternative is to show structural features common to the genus. Because the scFvs in the ‘190 Patent were claimed functionally instead of structurally, the patent disclosure was required to show either:
- a representative number of species, or
- common structural features of the large genus of scFvs capable of binding any target of clinical interest.
Mere Disclosure Of Examples of scFvs Was Insufficient To Show A Representative Species
In an effort to show that the patent disclosure contained a representative number of species, Juno pointed to the two working embodiments of scFvs disclosed in the patent. Each of the disclosed scFvs were shown to bind to different targets of clinical interest.
The Federal Circuit concluded that the mere disclosure of these two examples was insufficient to satisfy the written description requirement. According to the Federal Circuit, there was no rationale provided as to why these two disclosed examples were representative of the species. Also, the Federal Circuit found that the patent disclosure failed to provide any guidance to a skilled artisan as to how to identify which scFvs are capable of binding to what appears to be a limitless number of clinical targets. Thus, the Federal Circuit held that the two disclosed working embodiments of scFvs failed to show a representative number of species that fall within the genus of scFvs capable of binding to targets of clinical interest.
Knowledge Of Common Structural Features Of scFvs Was Insufficient To Show Structural Features That Are Common In The Genus
In an attempt to show that common structural features of its claimed scFvs were known, Juno offered expert witness testimony. The expert testified that the general structure of scFvs was known in the art for well over a decade. The expert also testified that because the general structure of scFvs was known, and because all scFvs function in the same way, which is to bind to targets, the two disclosed examples were representative of the structure of scFvs.
The Federal Circuit was not persuaded by the testimony because it provided no information regarding the specific structural features of the scFvs that cause them to bind to specific targets. According to the Federal Circuit, mere knowledge of general structural characteristics of scFvs was insufficient in the absence of knowledge of specific structural features of the scFvs that allow them to bind to specific targets of clinical interest. Thus, the Federal Circuit held that Juno had failed to disclose, either through its expert evidence or through its patent disclosure, the common structural features of the genus of scFvs capable of binding to targets of clinical interest.
The Challenges Of Satisfying The Written Description Requirement For Functionally Claimed Biological Compounds
The hallmark of written description is the requirement that inventors possess the entire scope of the claimed invention at the time of filing. As the Federal Circuit stated in Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336 (Fed. Cir. 2010): “The purpose of the written description requirement is to ensure that the scope of the right to exclude, as set forth in the claims, does not overreach the scope of the inventor’s contribution to the field of art as described in the patent specification.” In other words, meeting the written description standard requires that the scope of the patent claims is not incommensurate with the scope of the disclosure. The Juno v. Kite case shows that the Federal Circuit is strictly enforcing this standard when it comes to biological compositions that are claimed according to their functional properties.
In the Juno v. Kite case, the Federal Circuit provided some “guideposts” that may help applicants to avoid functionally claiming biological compounds that are incommensurate with the scope of the disclosure. According to the Federal Circuit, these guideposts include:
- providing a rationale as to why the disclosed species are representative of the genus;
- providing guidance to a skilled artisan as to how to identify species that fall within the claimed functional genus; and
- disclosing common structural features of the genus that are critical to carrying out the claimed function of the biological compounds.
Despite these guideposts, the Federal Circuit does not provide any definitive guidance in Juno v. Kite on the standard that applicants must meet to satisfy the written description requirement for functionally claimed biological compounds. Thus, the Juno v. Kite case provides only partial guidance to inventors as to how to ensure that patent claims covering functionally claimed biological compounds are not incommensurate with the scope of the disclosure.
To mitigate against an invalidity finding, inventors may want to take cues from the Federal Circuit in the Juno v. Kite case as to how the written description standard might be met for functional claims covering biological compositions. This might include providing a rationale as to why the disclosed examples are representative of the species, providing guidance regarding how to determine which species fall within the claimed genus, and/or disclosing structural features that are critical to the function of the species within the genus.
Alternatively, inventors might consider alternative claiming strategies, such as claiming the biological compositions according to their structural features. This approach might avoid the need to meet the ambiguous standard of satisfying the written description requirement for functionally claimed biological compounds.
About The Authors:
Jonathan B. Fitzgerald, Ph.D., is an associate at Snell & Wilmer. He is a registered patent attorney and has a Ph.D. in molecular physiology. His primary practice area involves preparing and prosecuting patent applications in the biotechnology and the life sciences fields.
Jeffrey D. Morton, Ph.D., P.C., is a partner at Snell & Wilmer. He is the chair of the firm’s Life Sciences and Medical Technology Industry Group and has more than 15 years of experience representing both start-up and large enterprises for their intellectual property and commercial law needs.