Federal Circuit Axes Antibody Claims for Hemophilia Treatment Under Amgen

The U.S. Court of Appeals for the Federal Circuit (CAFC) today in a precedential decision affirmed a district court’s grant of summary judgment that Baxalta, Inc. and Baxalta GmbH’s Hemophilia patent claims are invalid for a lack of enablement. The court said the facts of the case are “materially indistinguishable from those in Amgen.”

In Amgen v. Sanofi, the U.S. Supreme Court this past May upheld the Federal Circuit’s ruling that Amgen failed to enable a person skilled in the art to make and use its invention. The court said Amgen’s patent claims covering its Repatha cholesterol treatment were defined by meeting functional limitations, rather than by structure, and that the patent specifications didn’t enable the preparation of the full scope of the claims without undue experimentation.

Baxalta’s U.S. Patent No. 7,033,590 is directed to an alternative treatment for Hemophilia A. Its representative claim 1 recites “An isolated antibody or antibody fragment thereof that binds Factor IX or Factor IXa and increases the procoagulant activity of Factor IXa.” The inventors generated the antibodies by using a prior art method known as the “hybridoma technique” and performed four hybridoma fusion experiments that showed only 1.6% of the thousands of screened antibodies increased the procoagulant activity of Factor IXa. The ’590 patent ultimately disclosed the amino acid sequences of 11 antibodies that bind to Factor IX/IXa and increase the procoagulant activity of Factor IXa. The Federal Circuit vacated and remanded a prior judgment from the district court for erroneous claim construction, and on remand Genentech moved for summary judgment of invalidity for lack of enablement, which the district court granted.

On appeal, Baxalta argued that skilled artisans can obtain the full scope of claimed antibodies without undue experimentation by “using the routine hybridoma-and-screening process disclosed in the ’590 patent.” But, recapping the Supreme Court’s Amgen holding, the CAFC said the facts of Baxalta’s case are indistinguishable:

“The facts of this case are materially indistinguishable from those in Amgen. Claim 1 of the ’590 patent covers all antibodies that (1) bind to Factor IX/IXa; and (2) increase the procoagulant activity of Factor IXa.2 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…. To obtain the undisclosed but claimed antibodies, the written description directs skilled artisans to: (1) immunize mice with human Factor IX/IXa; (2) form hybridomas from the antibody-secreting spleen cells of those mice; (3) test those antibodies to determine whether they bind to Factor IX/IXa; and (4) test those antibodies that bind to Factor IX/IXa to determine whether any increase procoagulant activity…. 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…. In both cases, ‘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.’” [citations omitted]

Furthermore, said the court, “the patent does not disclose any common structural (or other) feature delineating which antibodies will bind to Factor IX/IXa and increase procoagulant activity from those that will not” or describe “why the eleven disclosed antibodies perform the claimed functions, or why the other screened antibodies do not.”

While Baxalta tried to argue its screening process does not require the type of trial and error described in Amgen and instead “predictably and reliably generates new claimed antibodies every time it is performed,” the court said “this does not take the process out of the realm of the trial-and-error approaches rejected in Amgen.” The court added:

“Even accepting as true that skilled artisans will generate at least one claimed antibody each time they follow the disclosed process, this does not take the process out of the realm of the trial-and-error approaches rejected in Amgen. Amgen made clear that § 112(a) requires inventors to enable the “full scope” of the claimed invention without unreasonable experimentation. Here, it is undisputed that to practice the full scope of the claimed invention, skilled artisans must make candidate antibodies and screen them to determine which ones perform the claimed functions…. This is the definition of trial and error and leaves the public no better equipped to make and use the claimed antibodies than the inventors were when they set out to discover the antibodies over which they now have an exclusive right. Under Amgen, such random trial-and-error discovery, without more, constitutes unreasonable experimentation that falls outside the bounds required by § 112(a).” [citations omitted]

Baxalta also attempted to argue that the district court’s ruling was inconsistent with the factors set forth in In re: Wands (1988), but the CAFC said the court has already distinguished Wands and Amgen and that it “does not interpret Amgen to have disturbed our prior enablement case law, including Wands and its factors.”

Laura Smalley of Harris Beach PLLC, who participated on a panel at IPWatchdog LIVE this week, titled “Best Practices for Enablement and Written Description After Amgen v. Sanofi,” and also recently wrote about best practices after Amgen, said the decision is”predictable” considering the Amgen ruling. She explained:

“Baxalta defined the claimed antibodies in entirely functional terms (“An isolated antibody or antibody fragment thereof that binds Factor IX or Factor IXa and increases the procoagulant activity of Factor IXa.”).  Although others could make and identify new claimed antibodies using a routine hybridoma-and-screening process described in the patent specification, that type of screening was found by Amgen v. Sanofi to be “trial and error” and insufficient to satisfy the enablement requirement.    The outcome in Baxalta was basically dictated by the rationale in Amgen v. Sanofi and shows that functional claims are very difficult to sustain after the Federal Circuit and Supreme Court’s decisions in Amgen v. Sanofi.”

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Author: billperry
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