Enabled to Claim the Unknown? Federal Circuit applies Amgen v. Sanofi to invalidate broad antibody claims

by Dennis Crouch

Baxalta Inc. v. Genentech, Inc., No. 22-1461, — F.4th — (Fed. Cir. Sept. 20, 2023).

The Federal Circuit recently affirmed a finding of invalidity for lack of enablement in Baxalta v. Genentech, holding that functional antibody claims were insufficiently enabled under 35 U.S.C. §112. Relying heavily on the Supreme Court’s Amgen v. Sanofi decision, the appellate panel found Baxalta’s disclosure to be analogous to Amgen’s “roadmap for further research” rather than a complete teaching of the invention. This result again calls into question the viability of broad functional claims post-Amgen and highlights the importance of structurally defining inventions, especially in unpredictable arts like biotechnology.

As mentioned, the case has close parallels and to the Supreme Court’s recent decision in Amgen Inc. v. Sanofi, 598 U.S. 594 (2023).  Amgen involved a functional-claimed antibody designed to inhibit PCSK9 activity.  The Supreme Court found that the broad claims encompassed a large number of antibody configurations while only describing a limited number of those, along with a trial-and-error roadmap for finding the additional embodiments.  Although some experimentation is permissible, a patentee cannot satisfy the enablement requirement by assigning a research project.  Ultimately, the Court concluded that Amgen had failed to enable the “full scope” of the claimed invention and that the claims were therefore properly held invalid as a matter of law.

As in Amgen, Baxalta’s patent also includes a functionally claimed isolated antibody:

1. An isolated antibody or antibody fragment thereof that binds Factor IX or Factor IXa and increases the procoagulant activity of Factor IXa.

‘590 Patent, Claim 1.

The invention involves a treatment for Hemophilia A to promote blood coagulation.  As you’ll note by looking at Claim 1, it does not claim any particular amino acid sequence or antibody structure, but rather claims all antibodies capable of binding Factor IX or IXa in a way that increases  its procoagulant activity.  The inventors went through a process of injecting Factor IX into mice, and collecting resulting antibody producing white blood cells (B-cells). Those B-cells were then fused with myloma (cancer) cells to promote rapid growth even in vitro. As those fused B cells continued their work, the resulting antibodies were screened to determine which ones increased the procoagulant activity.  Although this process is tedious, it was a familiar and known process at the time of the invention. The result was several hundred antibodies generally identified through the screening, although only 11 were sequenced and disclosed in the patent application.

Genentech’s accused product (Emicizumab) was not one of the 11 disclosed.  The court also noted that, unlike the disclosed antibodies, Emicizumab is a humanized bispecific antibody and would not have been identified through the patentee’s research approach. One note here, unlike in Amgen, the Baxalta patent is not limited to “monoclonal” antibodies even though the disclosed research protocol would only result that type of antibody.

The Patent Act requires that the patentee describe how to make and use the invention:

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 . . . to make and use the same.

35 U.S.C. § 112(a). Whether or not a particular invention has been enabled is seen as a question of law based upon underlying questions of fact.  Although courts would typically call this a “mixed question” of law and fact, the conceptual separation allows courts more leeway in preemptively deciding the legal question without having to submit the inquiry to the finder of fact (typically a jury).

In this case, Federal Circuit Judge Timothy Dyk served as the district court judge — sitting by designation in D.Del.  In a 2022 decision, Judge Dyk granted summary judgment of invalidity for lack of enablement. On appeal, the Federal Circuit affirmed — finding the facts of the case “materially indistinguishable from those in Amgen.”

There are millions of potential candidate antibodies, but the written description discloses the amino acid sequences for only eleven antibodies with the two claimed functions. . . Just like the roadmap rejected by the Supreme
Court in Amgen, the ’590 patent’s roadmap simply directs skilled artisans to engage in the same iterative, trial-and-error process the inventors followed to discover the eleven antibodies they elected to disclose.

Slip Op. Enablement of a broad genus can also be accomplished by disclosing common qualities of the genus. These are typically structural qualities, but the court here notes that the might include “other” features that help delineate the class.  An example might involve the mechanism of binding, for instance. The court found none of those in the disclosure.

The only guidance the patent provides is “to create a wide range of candidate antibodies and then screen each to see which happen to bind” to Factor IX/IXa and increase procoagulant activity. Amgen makes clear that such an instruction, without more, is not enough to enable the broad functional genus claims at issue here.

Id. (Quoting Amgen).  One question following Amgen is whether the case disturbed the Wands Factors associated with identifying “undue experimentation.” Here, the court wrote that there is “no meaningful difference between Wands’ ‘undue experimentation’ and Amgen’s ‘[un]reasonable experimentation’ standards.”  One difficulty with that result though is that the Wands Factors are generally questions of fact that, if in dispute, preclude summary judgment.  Here though, the court concluded that the case was so analogous to Amgen that summary judgment was appropriate — the effective implied conclusion is that there were not factual allegations presented by the patentee material enough to shift the outcome.

Baxalta reinforces that claimed inventions should be defined structurally insofar as possible, rather than solely by function. While claim breadth is undoubtedly desirable, applicants must now enable the full scope or risk invalidation post-Amgen. Even fields accustomed to broad functional claiming may require narrowing to structurally-defined elements, especially where some aspect of the design remains unpredictable.  A functional limit is potentially problematic any time a claim element has “millions” of possible embodiment designs.  On major caveat here of course is that these two cases are biotech focus and the USPTO in particular has largely resisted strongly expanding enablement doctrine outside of the chemical and biotech arts.  Another caveat of these pair of cases is that neither are combination claims. Rather, each simply claim a single component – the antibody.  I can imagine a situation where more leeway is given to functional components in a combination patent where substantial structure is provided by the combination, including other components in the combination.  Finally, also note that 112(f) is available for combination inventions to claim individual elements in means-plus-function form. That approach should typically save the claim validity at the cost of limited scope.

16 thoughts on “Enabled to Claim the Unknown? Federal Circuit applies Amgen v. Sanofi to invalidate broad antibody claims

  1. 5

    I find it ironic that the CAFC would have to invalidate a patent under enablement when my job was threatened as an examiner by having “too many enablement rejections.” The PTO just wants the allowance and maintenance fees; not quality examination. link to youtu.be Hence the issuance of another bad patent clogging up the court system and commerce for the economic benefit of the PTO administration. Enablement rejections are pretty rare, but are necessary occasionally. Too bad examiners can’t do it without risking their jobs or overtime pay.

  2. 4

    I can imagine a situation where more leeway is given to functional components in a combination patent where substantial structure is provided by the combination, including other components in the combination.

    Not when the structure is simply describing old things and the novelty is still described with functional language.

    1. 4.1

      What part of 35 USC has this “point of novelty” view of yours written?

      What part of 37 CFR?

      What part of MPEP?

      Heck, let’s even start with case law…

      1. 4.1.1

        What part of 35 USC has this “point of novelty” view of yours written?

        Heck, let’s even start with case law…

        Sure. 112 states THE SPECIFICATION shall enable the claim. Caselaw states that because the specification is written for the person of ordinary skill, the specification need not particularly enable known features, as it can rely upon the conventional knowledge in the art to fill in the gaps. This supplementary rule allows *the specification* to meet the 112a requirement by merely mentioning things the art conventionally knows how to do.

        But when there is a “point of novelty,” i.e. the specification begins to talk about something that is beyond the conventional knowledge in the art, the supplementary rule does not apply. There is no conventional knowledge to supplement the mere mention that occurs in the specification. In these cases the specification must include teachings to enable the scope claimed. When it does not the claim is not enabled. This is well documented in 35 USC (see 112a) in office procedure (see MPEP 2161.01) and in caselaw (see, e.g., Genentech, Inc. v. Novo Nordisk A/S, 108 F.3d 1361; “It is the specification, not the knowledge of one skilled in the art, that must supply the novel aspects of an invention in order to constitute adequate enablement.”)


          Granted, we could be talking past each other, but….

          Your assertions do not translate to the question that I put to you: I asked specifically about a certain phrase – a term of art – that you seem to want to misconstrue.

          That phrase is “Point of Novelty.”

          I am not asking about novelty – per se.

          I am not asking about teaching or enablement of novel aspects. Enablement is indeed a requirement across the board, and certainly is fact intensive.

          So your case citation is off (they rely on full scope of claim – not any Point of Novelty). I do like the case’s reference to Brenner (a patent is not a hunting license), but the case is MORE on whether or not something provided is enabling, rather than the emphasis of “Point of Novelty.” This case more supports MY position vis a vis how Big Pharma vitiates the possession at time of filing requirement for most all items claiming efficacy that meets the FDA requirements (as would be understood by a PHOSITA).

          MPEP 2161.01 does not help you. There, it lists the standard legal requirements for all inventions, and does not reflect the term of art of “Point of Novelty.” This appears to be the same error as in your case citation (certainly novel aspects need be enabled, but that is not what the term of art encompasses).

          And most certainly, 35 USC 112(a) does not help you.

  3. 3

    [T]he USPTO in particular has largely resisted strongly expanding enablement doctrine outside of the chemical and biotech arts.

    This is a small point, but I quibble with that “in particular.” The CAFC has been just as reluctant as the USPTO to apply “scope of enablement” considerations outside the chem/bio art space. Indeed, to my mind the USPTO is not taking any initiative on this point, but is rather just following the lead of its reviewing court.

    1. 3.1

      I agree w Dozens but I would be interested to hear more from Dennis about whether there is evidence/argument to support his contention.

    1. 2.1

      Not at all. In most pharma cases functional claims are rarely the only claims that cover the active agent. It never occurs with small organic molecules – there is always a structure claim for the specific molecule. A functional claim would only be secondary in an attempt to greatly expand the coverage way beyond the molecule. Same with proteins (think Wegovy and the weight loss drugs all advertised on TV). Functional claims only show up after the molecule itself – the specific protein sequence – has been claimed. It’s with antibodies where broad functional claims without a specific sequence most often show up. This is a very small percentage of drugs. The sequences are available but the brand owner is attempting to claim an entire functional effect rather than a specific molecule. Ariad v Lilly dealt with this a while ago, and Amgen just more clearly says the same thing.

      1. 2.1.1

        Thanks for the additional info DVan.

        My point, however, was that Amgen is like Alice in the sense that both decisions materially affect and restrict the ability to obtain claims which used to be regularly obtainable.


          restrict the ability to obtain claims which used to be regularly obtainable.

          What? Whatever can be said about judicial exceptions, enablement is statutorily described and has been around forever. The fact that they have been “regularly obtainable” just means the office would issue them, not that they were ever valid. Ariad was decided in 2010 and uses essentially the exact same logic, and that doesn’t stop claims from issuing despite functionally-based WD infirmities. To that point, it isn’t clear that the office still won’t issue these claims today. The office issues invalid claims all the time.


            Agree – and yet my admonition of, “ Do your F N jobs” is (somehow) routinely taken issue with.


  4. 1

    >Although this process is tedious, it was a familiar and known process at the time of the invention.

    Outside my field… what was the real innovation here? Recognizing that binding to factor IX or IXa increases procoagulant activity? Or were they just the first to apply a known, “tedious” technique to this particular problem (with predictable results?)

    1. 1.1

      Generally speaking, a measured activity of any protein (note: not necessarily the protein’s only activity or it’s most important activity) can be inhibited or enhanced (or otherwise altered) via the binding of a second protein (like an antibody). That’s a concept that is about as old as the concept that proteins exist and do stuff in cells. What’s useful and patent-worthy is identifying the proteins (like antibodies) that achieve the desired changes with high specificity (i.e., not interfering with the activity of untargeted molecules). While predictability has improved over the many years that scientists have been studying the structure/function relationships in proteins, positive identification of the “best” antibodies for a particular effect remains something that requires actual reduction to practice and testing. In other words, the critical PHYSICAL STRUCTURE(S) responsible for the desired result can not be known until the actual proteins are sequenced and studied.

      A set of eleven sequenced proteins MIGHT reveal a “motif” or sequence of amino acids that is particularly useful. Such structural information is often obtained and claimed and that sort of patent claim would have a much higher chance of being found enable relative to the “pure” functional claim that was at issue here.

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