In the Aftermath of Amgen v. Sanofi, Federal Circuit Finds Functional Antibody Claims Invalid for Lack of Enablement

December 13, 2023

Reading Time : 2 min

Applying the Supreme Court’s Amgen v. Sanofi decision for the first time,1 the Federal Circuit recently affirmed a district court decision finding claims to antibodies characterized by their ability to bind a particular complex and increase its pro-coagulant activity.

The appeal in this case stemmed from a district court case in which Baxalta sued Genentech for patent infringement based on claims that were generally directed to isolated antibodies or antibody fragments that (1) bind Factor IX or Factor IXa and (2) increase the pro-coagulant activity of Factor IXa.

At the district court, Baxalta’s claims were held invalid for lack of enablement at the summary judgment stage. On appeal, Baxalta argued that persons skilled in the art can follow the established hybridoma-screening process described in its patent to obtain antibodies within the scope of its claims. According to Baxalta, that sort of routine screening does not amount to undue burden.

The Federal Circuit rejected this argument, finding the claims in the Baxalta patent materially indistinguishable from the claims held invalid by the Supreme Court in Amgen v. Sanofi. In Amgen, the Supreme Court explained that “[i]f a patent claims an entire class of processes, machines, manufactures, or compositions of matter, the patent’s specification must enable a person skilled in the art to make and use the entire class. In other words, the specification must enable the full scope of the invention as defined by its claims. The more one claims, the more one must enable.”  

In reaching its decision in Baxalta, the Federal Circuit relied heavily on Amgen. Specifically, the court held that the claims of Baxalta’s patent potentially covered millions of antibodies, while the specification disclosed the amino acid sequences of just 11 antibodies. As in Amgen, “nothing in the specification [teaches] how to identify any antibodies complying with the claim limitations other than by repeating the same process the inventors used to identify the . . . examples disclosed in the specification.” “The patent does not disclose any common structural (or other) feature delineating which antibodies will bind to Factor IX/IXa and increase pro-coagulant activity from those that will not. Nor does the patent describe why the eleven disclosed antibodies perform the claimed functions, or why the other screened antibodies do not.” Instead, it leaves it to a person of skill in the art to make and test antibodies through trial and error.

Finally, the Federal Circuit provided its understanding that there is “no meaningful difference between Wands’ ‘undue experimentation’ and Amgen’s ‘[un]reasonable experimentation’ standards,” further stating that it did not interpret Amgen to have disturbed the Wands factor analysis.

Practice Tip: Under current law, broad genus claims are unlikely to be enabled by a specification that merely describes methods by which species of that genus can be identified. Instead, the specification should venture to identify some general quality common to members of the genus.

Baxalta Inc. v. Genentech, Inc., 81 F.4th 1362 (Fed. Cir. 2023).


1 Amgen Inc. v. Sanofi, 143 S. Ct. 1243 (2023).

 

Share This Insight

Previous Entries

IP Newsflash

October 1, 2025

In a recent final written decision, the PTAB determined that a reference patent was not prior art, despite the petitioner’s post‑filing attempt to correct its petition. While the petitioner argued that it intended to rely on the patent application’s earlier date of publication, both the corrected petition and the expert declaration continued to reference the issued patent rather than the published application.

...

Read More

IP Newsflash

September 30, 2025

The USPTO Director recently granted a petitioner’s request for rehearing of the decision discretionarily denying institution of inter partes review, ultimately vacating the original decision, and referring the petition to the board for an institution decision.

...

Read More

IP Newsflash

September 25, 2025

In considering claims to a method of reducing cardiovascular events, the Federal Circuit held that the term a “clinically proven effective” amount did not render the claims patentable over the prior art. Specifically, the Federal Circuit held that the “clinically proven effective” amount, whether limiting or not, could not be used to distinguish the prior art because the claims also specified the exact amount of the drugs to be administered in the method. The Federal Circuit also rejected patentee’s evidence of unexpected results because that evidence was tied solely to the “clinically proven effective” limitation.

...

Read More

IP Newsflash

September 24, 2025

The Federal Circuit reversed a district court’s denial of judgment as a matter of law on non-infringement, thereby setting aside a $106 million jury verdict, after holding that prosecution history estoppel barred the patentee from asserting infringement under the doctrine of equivalents.

...

Read More

IP Newsflash

September 17, 2025

A magistrate judge in the District of Delaware issued a Report and Recommendation, that found the sole asserted claim was a “single means” claim and therefore invalid for lack of enablement. In reaching that conclusion, the magistrate judge rejected the patentee’s argument that the preamble of the claim disclosed a second element that satisfied the combination requirement of Section 112, paragraph 6 because the preamble simply recited a descriptor of the very apparatus that was the subject of the means-plus-function limitation in the body of the claim. The district court judge presiding over this case has scheduled a hearing to review the magistrate’s ruling.

...

Read More

IP Newsflash

September 9, 2025

The Federal Circuit has affirmed the PTAB’s determination that a patent challenger did not show the challenged claims were unpatentable for obviousness. The Federal Circuit concluded that substantial evidence, which included expert testimony, showed there was no motivation to combine the references.

...

Read More

IP Newsflash

August 29, 2025

In a recent order addressing four IPR proceedings, the PTAB exercised its inherent authority under 37 C.F.R. § 42.5(a) to sua sponte authorize post-hearing discovery on a potentially dispositive privity issue. The order followed a Director review decision that vacated and remanded earlier IPRs involving the same parties, patent family, and privity issue. 

...

Read More

IP Newsflash

August 29, 2025

The Patent Trial and Appeal Board denied institution of an inter partes review petition in part because it determined that a patent reference was not prior art under the common ownership exception of pre-AIA 35 U.S.C. § 103(c)(1).

...

Read More

© 2025 Akin Gump Strauss Hauer & Feld LLP. All rights reserved. Attorney advertising. This document is distributed for informational use only; it does not constitute legal advice and should not be used as such. Prior results do not guarantee a similar outcome. Akin is the practicing name of Akin Gump LLP, a New York limited liability partnership authorized and regulated by the Solicitors Regulation Authority under number 267321. A list of the partners is available for inspection at Eighth Floor, Ten Bishops Square, London E1 6EG. For more information about Akin Gump LLP, Akin Gump Strauss Hauer & Feld LLP and other associated entities under which the Akin Gump network operates worldwide, please see our Legal Notices page.