USPTO Updates Guidance on Enablement

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In 2023, the U.S. Supreme Court affirmed invalidity of two Amgen patents based on a lack of enablement for broad genus claims that would potentially encompass millions of antibodies. The Court[1] explained that Amgen’s teaching of how to make and use their invention was little more than research assignments, and therefore requires undue experimentation to arrive at the breadth of the claims. In January of 2024, the USPTO updated its guidelines for assessing compliance with the enablement requirement based on the Amgen decision.

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In order to obtain a U.S. patent, the applicant must provide an enabling disclosure, that is, “a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same.”  35 U.S.C. § 112(a).  Although this requirement has been codified in the Patent Statute since at least 1952, its interpretation and application continue to evolve in light of new technologies.  The recent Supreme Court decision captioned Amgen Inc. v. Sanofi and the response of the U.S. Patent and Trademark Office (USPTO) to that decision well illustrate this continuing evolution of U.S. patent law.

Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) is a protein made by the liver that regulates low-density lipoprotein (LDL) or “bad” cholesterol.  PCSK9 Inhibitors are a class of drugs that lower “bad” cholesterol. Amgen sought and received patents in 2011 specifically identifying 26 amino acid sequences for antibodies that would block or inhibit PCSK9.

In 2014, Amgen obtained two more patents, US 8,859,741 and US 8,829,165, each directed to a genus of antibodies capable of performing a certain function related to lowering LDL.  After the patents were granted, Amgen sued their competitor, Sanofi, for patent infringement.  Sanofi then challenged both patents on the grounds of lack of enablement. Sanofi alleged, among other things, that there are millions of antibodies encompassed by the broad claims and that a person of skill in the art would have to exercise undue experimentation to arrive at the breadth of the claims.

The district court sided with Sanofi holding that the broad genus claims lacked enablement under 35 U.S.C. § 112(a).  The Court of Appeals for the Federal Circuit (CAFC) affirmed that decision.[1]  Amgen appealed the appellate decision to the Supreme Court, which upheld the CAFC’s affirmance of the district court decision.  We have previously published a newsletter article[2] discussing the 2023 Supreme Court decision penned by Associate Justice Gorsuch.

In response to the Supreme Court’s decision, the USPTO published updated guidelines[3] for assessing enablement in utility applications and patents. 

Historically, enablement has been assessed based on factual considerations referred to as “the Wands factors.”  These considerations are derived from a 1988 CAFC decision[4] which outlined how to assess whether “undue experimentation” is required to make and use an invention. The Wands factors include: (A) the breadth of the claims, (B) the nature of the invention, (C) the state of the prior art, (D) the level of one of ordinary skill, (E) the level of predictability in the art, (F) the amount of direction provided by the inventor, (G) the existence of working examples, and (H) the quantity of experimentation needed to make and use the invention based on the content of the disclosure.

The updated guidelines summarize the CAFC’s Amgen Inc. v. Sanofi decision, which analyzed the Wands factors with reference to Amgen’s broad functional genus claims.  In the course of affirming that CAFC decision, the Supreme Court clarified the requirements for enablement under 35 U.S.C. § 112(a).  Specifically, the Court explained that a need for a “reasonable” amount of experimentation does not necessarily mean that a patent claim is invalid for lack of enablement, , stating “[w]hat is reasonable in any case will depend on the nature of the invention and the underlying art.”

Based on these decisions, the updated guidelines outline how one should assess “reasonable experimentation.”  Unsurprisingly, the guidelines maintain that the Wands factors will continue to be employed to assess whether experimentation required to make and use a claimed invention is reasonable or not.  As has been highlighted by the courts in any case regarding enablement, the question of enablement is highly fact-specific, and must be decided on a case-by-case basis.  The updated guidelines reference several post-Amgen enablement decisions that can be informative in how one might go about determining whether the enablement requirement has been met.

For example, Baxalta[5] is a post-Amgen CAFC decision also involving antibodies, specifically antibodies for treating hemophilia. The claims at issue are functional claims directed to an antibody that achieves certain binding properties.  The CAFC concluded that the facts of Baxalta were “indistinguishable from those in Amgen,” and because the claims encompass potentially millions of antibodies while only 11 antibodies and methods of producing them are described in the specification, the broad functional claims are not enabled.

Another post-Amgen enablement case, Medytox,[6] was not directed to antibodies.  Rather, the claims at issue are related to using an animal protein-free botulinum toxin composition that exhibited certain performance.  More particularly, a claim limitation in question requires that a response rate that was “50% or greater” when compared to a comparative botulinum toxin composition.  As there is no upper limit on the claim, the courts interpreted the upper limit to be 100%.  There are only three examples in the specification of a composition having a response rate of 50% or greater. The PTAB applied the Wands factors and concluded that undue experimentation would be required to achieve a rate higher than 62%, and as such, the claims are not enabled.  The Federal Circuit agreed with the PTAB.

Finally, the updated guidelines summarized Starrett,[7] which relates to enablement of a non-transitory computer readable medium for maintaining augmented telepathic data for telepathic communication.  In this instance, the claims potentially cover 140 trillion embodiments.  Citing Amgen, the CAFC noted the axiom that “the more one claims, the more one must enable.”  The decision concluded that the Examiner properly applied the Wands factors to the claims at issue and the full breadth of the claims is not properly enabled by the specification.

In view of Amgen and the various enablement decisions highlighted by the updated guidance, it is clear that the Wands factors remain the standard for assessing enablement.  It is also clear that the question of enablement is highly dependent on the facts of a specific case.  The bar for enablement is higher for less predictable technologies such as chemistry and biotechnology. As such, applicants should bear in mind the level of experimentation required to make and use their invention using the Wands Factors as a guide.