The Supreme Court’s recent decision in Amgen v. Sanofi puts a spotlight on enablement of functionally defined claims. Future developments may shed light on a number of remaining questions for patent applicants. Here are five areas to watch:
1. What is the impact on other technology?
The Court emphasized that “aspects of antibody science remain unpredictable.” How will courts evaluate the predictability of other technologies, such as nucleic acid and gene editing technologies, small molecules, and artificial intelligence?
Providing some direction, the Court explained that it might suffice to disclose one or a few examples if there is “some general quality” running through the class that would reliably enable a person skilled in the art to make and use the entire class of molecules. This suggests that other technologies may be better situated to withstand enablement attacks. As an example, unlike antibodies, the target of an antisense oligonucleotide can be determined by its sequence alone, suggesting that the reasoning applied by the Court to antibodies to limit the scope of claims may not be as generalizable as it first appears.
2. What is the outlook for other antibody claim types?
It is not yet clear how the Court’s decision will be applied to other antibody claim types, particularly where the innovation is not centered on antigen binding properties of an antibody. Examples include chimeric antigen receptor therapies, antibody-drug conjugates, modifications to antibodies outside of the antigen binding region (e.g., Fc mutations), and methods that use antigen binding moieties. Functional genus claims that sweep in a broad class of well-characterized antigen binders may not suffer from the same unpredictability in determining the sequence of antibody variable domains that are responsible for conferring antigen or epitope binding, which the Court relied upon heavily in making its determination. These types of inventions may be in a stronger position to obtain broader claims.
3. How will AI impact antibody patents going forward?
Predictability of a given technology is an important consideration for enablement. In this case, the Court noted that translating an antibody’s amino acid “sequence into a known three-dimensional structure is still not possible.”
But artificial intelligence (AI) and machine learning based computational models for predicting protein structures are rapidly evolving. Will courts respond in the future by allowing broader functional claims as the link between amino acid sequence, three-dimensional structure, and functional properties becomes more predictable?
At a minimum, applicants should consider how developments in AI can be harnessed to enable broader claim scope at the time of filing a new application and even during prosecution as these developments continue to play out.
4. Will the doctrine of equivalents (DOE) be applied more regularly moving forward?
The doctrine of equivalents has rarely been applied to claims reciting sequences of large molecules. But in Ajinomoto v. ITC (2019), the Federal Circuit made it clear that DOE can apply to a claim reciting amino acid sequences.
In the future, we may see more examples of patent owners asserting DOE, particularly when enablement of broader, literally infringed claims is questionable. Patent owners and applicants should monitor how DOE-related issues play out in the district courts and at the Federal Circuit.
5. Are claims that recite conservative substitutions or percentage identity thresholds still viable?
While not ruling out enablement of such claims, the Supreme Court’s opinion may cast a shadow over enablement of claims reciting conservative substitutions or percentage identity thresholds for antibodies or other proteins. The Court noted that conservative substitution “requires scientists to make substitutions to the amino acid sequences of antibodies known to work and then test the resulting antibodies to see if they do too,” concluding that it was “[n]ot much different” than a roadmap for de novo antibody discovery.
The Court left the door open for enablement of conservative substitution for other claims, such as where the inventor identifies a quality common to the functional embodiments. But the holding could have a wide-ranging impact on protein and nucleic acid claims beyond antibodies, such as enzyme and nucleic acid sequences that allow sequence variation.
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 See, e.g., Ruffolo et al., Fast, accurate antibody structure prediction from deep learning on massive set of natural antibodies, Nat. Commun. 14, 2389 (2023).