AntiBody Fragment: A Description of the Federal Circuit?

by Dennis Crouch

Baxalta Inc. v. Genentech, Inc., 2020 WL 5048435 (Fed. Cir. Aug. 27, 2020)

Although not en banc, this case was picked-up by five different Federal Circuit judges with two separate opinions and one recusal.

Sitting by designation as a D.Del. district court, Judge Dyk sided with the accused infringer Genentech by narrowly construing Baxalta’s US7033590.  Although perhaps most jury members would need some help with definitions, the disputed terms are incredibly basic and fundamental to anyone involved with biotech. Disputed terms:

  • Antibody; and
  • Antibody fragment.

Following claim construction, the parties stipulated to non-infringement.

On appeal, the Judges Moore, Wallach, and Stoll took up the claim construction question.  However, after oral arguments Judge Stoll recused herself and Judge Plager stepped-in.  The new panel rejected Judge Dyk’s claim construction and consequently vacated the non-infringement judgment.

The patent is directed to a treatment for hemophilia and claims “an isolated antibody or antibody fragment” that binds to FactorIXa and increased its procoagulant activity.

Judge Dyk explained that the term antibody might have various potential meanings.  But here, the patentee expressed a narrower definition within its specification with the following statement:

Antibodies are immunoglobulin molecules having a specific amino acid sequence which only bind to antigens that induce their synthesis. . . . Each immunoglobulin molecule consists of two types of polypeptide chains. Each molecule consists of large, identical heavy chains (H chains) and two light, also identical chains (L chains).

‘590 at Col. 5.  Applying this portion of the patent, the district court limited the scope of antibody to molecules having one set of identical H-chains and a set of identical L-chains.

Genentech’s product uses an antibody organized with a variety of H- and L- chains (not all the H-chains are identical to one another). Thus, Judge Dyk’s requirement of identical chains led to the admission of non-infringement.

On appeal, the Federal Circuit took Judge Dyk to task — finding that the patent did not suggest such a narrow definition of the term. Dependent claim 4, for instance, identifies the antibody as being selected from “the group consisting of … a chimeric antibody, a humanized antibody, … [and] a bispecific antibody.”  The court explains that none of these antibody types in the dependent claim conform with the narrow definition of the term as used in claim 1.

The district court’s construction which excludes these explicitly claimed embodiments is inconsistent with the plain language of the claims. . . . The plain language of these dependent claims weighs heavily in favor of adopting Baxalta’s broader claim construction.

Slip Op.  The court then looked at the definition discussed by Judge Dyk and concluded that it was a “generalized introduction” rather than a “definitional statement.” In this process, the court noted the lack of patent-profanity such as “the present invention is … ”  The court’s conclusion is supported by other aspects of the specification that refers to the bispecific and other forms of antibodies that do not conform to Judge Dyk’s definition. The result: “The claim construction excluding these disclosed and claimed embodiments is therefore incorrect.”

The case also included some prosecution history. In particular, the patentee amended its claims from “antibody derivative” to “antibody fragment.” On appeal, the court found no clear statement from the prosecution history regarding how that amendment modified the scope. Without a ‘clear statement’ there is no prosecution disclaimer leading to disavowal of scope.

17 thoughts on “AntiBody Fragment: A Description of the Federal Circuit?

  1. 4

    This appears to be the claim construction opinion.
    link to

    It includes an entire subsection about the dependent claims, and also some discussion about this language that’s either a definition or a “generalized introduction.”

    I don’t yet know if I find it persuasive, but probably worth reading before opining confidently about individual judges’ thought processes.

  2. 3

    The Court fails to indicate the important fact of whether the dependent claims which show a broader claim intent were original claims or claims added by amendment. If original, they are of course part of the specification as filed.

    1. 3.1

      The court does address this. The original claims recited “antibody derivatives”, not “antibody fragments”.

      Judge Dyk found that the listed categories of claim 4 may be “antibody derivatives,” but were not “antibodies” according to the narrow definition of the spec. Thus, there is no inconsistency between assigning a narrow definition to “antibody” and recognizing claim 4 as covering “antibody derivatives” which may be broader.

      Then the claims were amended to change “antibody derivatives” to “antibody fragments.”

    2. 3.2

      Are you saying that if by amendment, then they cannot be reflective of the specification as filed?

      Of course, that would mean that they were new matter, eh?

  3. 2

    Dyk, who should know better, appears to be applying the examiner-like “pin-cite (out of context)” meme based on a desired result of “no patent for you.”

    Sadly, Judge Dyk often appears to have wholly, and almost gleefully accepted the firehose-training from the Supreme Court in regards to The Ends Justify the Means.

      1. 2.1.4

        It doesn’t matter what you invented. It matters how you describe, in the written description, what you invented. No more, and potentially substantially less (enablement).


          Very true, but no skilled artisan reading the spec here would take from it what Judge Dyk purported to find. This was picking-&-choosing on steroids, in the service of achieving a particular outcome that finds little warrant in either statute or case law. The CAFC got this one right.


          Of course, that is viewed through the lens of PHOSITA (which, through the Supreme Court — for other reasons — has been ‘super’ augmented).

      2. 2.1.5

        Not just J. Dyk but most of the CAFC. They hire people that have degrees in the technological area who then read it and are instructed to invalidate claims.

        So the people with degrees decide what your invention is with no ability for the patentee to argue to refute them and then the kings/queens pronounce your d e a th sentence.

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