On May 18, 2023, the Supreme Court unanimously affirmed the Federal Circuit's decision, Amgen Inc. v. Sanofi, 987 F.3d 1080 (Fed. Cir. 2021), that the claims of two of Amgen's patents were invalid for lack enablement. The involved patents, US 8,829,165 and US 8,859,741, are directed to monoclonal antibodies that block binding of the protein PCSK9 to LDL (low-density lipoprotein) receptors. Binding of PCSK9 to LDL receptors results in destruction of the receptors and eliminates their ability to remove LDL (the so-called "bad" cholesterol) from the bloodstream.
What You Need to Know
- The claims at issue were genus claims that did not recite any sequences for the antibodies. Instead, they claimed the antibodies by function, i.e., binding to at least one of 15 listed amino acids in PCSK9 such that when the antibody is bound to PCSK9, binding of PCSK9 to LDL receptor is blocked.
- The Court confirmed that Amgen's claims, which would have blocked any competitive antibody drug treating high LDL levels by binding to one or more of the listed amino acids and blocking PCSK9, lacked sufficient enablement. According to the Court, the patents' specifications only offered vague advice suggesting a 'trial and error' approach to those skilled in the art.
Requirements for Enablement
The Patent Act requires the specification of a patent to disclose sufficient information about the claimed invention "to enable any person skilled in the art ... to make and use the same." The question for the Court was whether it was sufficient for the specification to teach individuals skilled in the art to "make and use" the claimed invention or whether instead it must teach skilled artisans how to practice the full scope of the claimed invention without undue experimentation. A primary reason for the enablement requirement is to inform the public on how to carry out the claimed invention.
Proceedings in Lower Courts
After trying the case at the district court level, a jury found that Sanofi failed to prove that the asserted claims were invalid for lack of written description and enablement. Sanofi moved for motion for judgment as a matter of law (JMOL) on both issues, and the district court granted the motion for JMOL on enablement. The district court noted that the only ways for a person of ordinary skill to discover undisclosed claimed embodiments would be through either "trial and error, by making changes to the disclosed antibodies and then screening those antibodies for the desired binding and blocking properties," or else "by discovering the antibodies de novo" according to a randomization-and-screening "roadmap." Amgen appealed. Sanofi did not cross-appeal on written description.
The Federal Circuit agreed with the district court. It reiterated that, to prove a claim is invalid for lack of enablement, a challenger must show by clear and convincing evidence that a person of ordinary skill in the art would not be able to practice the claimed invention without "undue experimentation." This analysis usually takes place by weighing many factual considerations, the so-called "Wands factors." The Federal Circuit held that in this case, because the claimed antibodies had broad functional limitations and the specification only had narrow examples and guidance, "no reasonable jury could conclude under these facts that anything but 'substantial time and effort' would be required to reach the full scope of claimed embodiments."
Supreme Court Decision
The Court agreed with the Federal Circuit's understanding and analysis of the Patent Act and its application to the enablement standard. With respect to functional claims, the requirement for sufficient enablement was succinctly stated by the Court: "[t]here is no special rule for functional or genus claims, but the more that is claimed, the more that must be enabled." The Court noted that while some level of experimentation is acceptable for enablement, the level of effort required should not border on "trial and error."
The Court rejected Amgen's arguments that the Federal Circuit created a "new" standard where enablement depended on the time and effort it would take to make all or substantially all possible embodiments of a given invention. When undisclosed embodiments can be made predictably, even if it takes considerable time, "the cumulative effort needed to make and use every single embodiment of the claimed invention is unproblematic."
However, the combination of "unpredictability of the science" and "a broad functional claim" that encompasses far more than provided in the patent's examples and guidance, leaves persons of skill in the art with "no option but to engage in trial and error using well-established techniques to generate candidate antibodies that would then still need to be tested to ascertain whether they came within the claimed genus." Testing whether an antibody even possesses the claimed functionality was a point the Court reiterated as being consistent with both the Court's and Federal Circuit precedent as weighing against such claims being enabled.
On public policy grounds, the Court noted at least two risks associated with broad functional claiming. Firstly, granting claims reciting a broad functionally claimed genus to a company that has discovered only a certain species "creates a very real risk that important medical treatments will never reach the market." Secondly, and possibly an "even greater risk" is that a company claiming a broad functional genus would only discover species that are "not efficacious at all." The Court cited the example of Pfizer's PCSK9 antibody that was ultimately discontinued after poor clinical results as a case where such a non-enabled claim would stifle innovation and deprive patients of PCSK9 antibody therapies if broad claims such as those at issue were valid.
Prospective Litigants
This decision is likely to have a considerable impact on both patent enforcement and defense of patents containing functionally claimed broad genus claims, particularly in the life sciences. Patentees with such claims could defend against challenges by emphasizing predictability and common structure found in the claimed genus as well as in any expressly described species. Patentees with related applications still pending could pursue claims reciting additional structure in those applications, e.g., the sequences of the complementarity determining regions for one or both chains of the antibodies. Patentees who do not have related applications pending could consider whether to file a reissue application to pursue such claims.
Patent Prosecution
For patent practitioners, this ruling underscore the importance of thorough and detailed patent specifications that enable the full scope of the claimed invention, particularly when the claims are broad or functional in nature. If a patent claim seeks to cover an entire genus or class of things defined by their function, practitioners must ensure that the specification provides enough information for a skilled person in the art to make and use the full scope of the claimed invention without excessive experimentation. One way to try to achieve this is to provide examples that represent a variety of species. This holds especially true in unpredictable fields. For example, for the present claims, one could provide examples of antibodies that bind one, two, three, four, etc. of the listed amino acids and block binding. The bottom line from this decision is: the broader the claim, the more one must enable.
Summary
While the Sanofi v. Amgen decision does not signal the end of all genus claims, it does reinforce the traditional enablement requirements and emphasizes the critical role of the patent specification in supporting the claims. The ruling sends a clear message that broad, functionally defined claims require a robust disclosure in the specification to meet the enablement standard.
