Last week, a federal court in Delaware unsealed an opinion supporting its grant of summary judgment that U.S. Patent No. 7,033,590 (“the ’590 Patent”) is invalid for lack of enablement.[1] The ’590 Patent is owned by Baxalta Inc. (“Baxalta”), a subsidiary of Takeda Pharmaceutical Co. Ltd (“Takeda”).

As we previously discussed, Baxalta sued Roche’s subsidiary Genentech Inc. (“Genentech”), alleging that that the blockbuster drug Hemlibra, made by Genentech, infringes Baxalta’s ’590 patent. Genentech denied Baxalta’s allegations and alleged, inter alia, that claims 1–4, 19, and 20 of the ’590 patent were invalid for lack of enablement.[2]

The ’590 patent is entitled “Factor IX/Factor IXa Activating Antibodies and Antibody Derivatives” and was issued on April 25, 2006. Its patent application, filed on September 14, 2000, claimed priority to a foreign application filed on September 14, 1999. At issue are claims 1–4, 19, and 20 of the ’590 patent, which cover a genus of antibodies that bind to factor IX/factor IXa, thereby increasing the procoagulant activity of FIXa and restores blood clotting process in hemophilia A patients.

Claim 1 of the’590 patent recites:

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

The litigation related specifically to infringement of the ’590 patent’s claims by Genentech’s Hemlibra (emicizumab), which was approved by the FDA for treatment of hemophilia A on October 4, 2018.[3] Baxalta itself has never commercialized a treatment for hemophilia A based on any of the antibodies covered by this patent.[4]

In his memorandum opinion, visiting Circuit Judge Timothy Dyk, who normally sits on Federal Circuit, held that the relevant claims of Baxalta’s patent were invalid for lack of enablement after applying the test articulated in In re Wands,[5] because undue experimentation would be required for a person skilled in the art to make and use the claimed invention.[6] The court found that neither the accused claims themselves nor the specification of the ’590 patent provided sufficient “guidance as to how to identify which antibodies will satisfy the claim limitations, nor [does it] describe what structural or other features of the disclosed antibodies cause them to bind to Factor IX/IXa or to increase the procoagulant activity of Factor IXa.”[7]

More specifically, based on the Wands factors, the Court cited to the following as supporting its finding of lack of enablement: (1) large amount of experimentation was needed because the number of candidates identified in the ’590 patent “number in the millions;” (2) there was no guidance as to how to identify the antibodies other than by trial and error; (3) the patent provided a very limited amount and variety of working examples; (4) the field of art (antibodies) was unpredictable; and (5) the breadth of the claims were too broad.[8] The Court concluded that “where, as here, there are a large number of potential candidates, few working examples disclosed in the patent, and no guidance in the specification as to how to practice the full scope of the invention except to use trial and error to narrow down the potential candidates to those satisfying the claims’ functional limitations—the asserted claims are not enabled.”[9]

The Court identified several Federal Circuit cases to support its finding that the asserted claims were not enabled as to their functional limitations.[10] For example, the Court points to Amgen Inc. v. Sanofi, Aventisub LLC, which we previously discussed here, where the Federal Circuit noted that where the patent at issue contained claims with broad functional language, the hurdles for fulfilling the enablement requirement were high.[11] There, the Federal Circuit found a lack of enablement on grounds that the claims were “far broader in functional diversity than the disclosed examples, [and] the only ways for a person of ordinary skill to discover undisclosed claimed embodiments would be through either trial and error… or by discovering the antibodies de novo.[12] Judge Dyk also compared this case to Idenix Pharms. LLC v. Gilead Scis. Inc.,[13] Wyeth & Cordis Corp. v. Abbott Labs.,[14] and Enzo Life Scis., Inc. v. Roche Molecular Sys., Inc.,[15] to analogize the situation “where the inventors had identified a small number of compounds within the scope of the claims and the court found the claims were not enabled given the breadth of the claims and the lack of sufficient guidance in the specifications.”[16]  We discussed several of these cases here.

The Court also found that the functional scope of the ’590 patent was not sufficiently represented by working examples.[17] Rather, the Court concluded that the ’590 patent merely “disclose[d] a starting point for further research.”[18] For example, the ’590 patent did not provide any working examples of two of the four Markush-group members cited in its asserted claims, nor provide any guidance in its specification for one skilled in the art to identify those isotopes.[19]

Finally, the Court also held that the ’590 patent “does not remotely enable” the accused product, emicizumab. “None of the 11 disclosed antibodies in the specification increase the procoagulant activity of factor IXa more than 3.75%,” while emicizumab increases procoagulant activity by approximately 10%.[20] Furthermore, emicizumab was a bispecific humanized antibody and the ’590 patent provided no working examples of either a bispecific or humanized antibody.[21] Baxalta’s expert conceded that the patent’s language about the covered antibodies and their therapeutic utility was merely “aspirational”[22] and the Court concluded that it could not “allow Baxalta to provide a starting point for further research and then claim someone else’s solution to the problem.”[23]

Potential Impact

This decision follows the Federal Circuit’s judgment as a matter of law for lack of enablement in Amgen Inc. v. Sanofi, Aventisub LLC, for which a petition for a writ of certiorari has been filed as discussed here.  That petition raises the question of whether enablement is “a question of fact to be determined by the jury . . . as [the Supreme] Court has held,” or whether it is “a question of law that the court reviews without deference . . . as the Federal Circuit holds.”  Here, Judge Dyk held that “no reasonable jury could find the full scope of the asserted claims of the ’590 patent are enabled.”[24]

In view of the trend toward higher standards for written description and enablement for antibody claims and claims reciting broad functional language, patent drafters will be well-advised to provide more working examples in general, working examples for every Markush group, and more guidance in the patent specification for how to identify candidates within the claimed group. We will continue to follow further developments including a potential appeal of this decision and the Supreme Court’s decision on Amgen’s petition.

[1] Memorandum Op. at 1, Baxalta Inc. v. Genentech, Inc., No. CV 17-509-TBD (D. Del. Jan. 13, 2022).

[2] Id.

[3] Memorandum Op., supra note 1, at 8, 19.

[4] Id. at 16.

[5] 858 F.2d 731, 737 (Fed. Cir. 1988).

[6] Memorandum Op., supra note 1, at 5.

[7] Id.

[8] 29 to 31.

[9] Id at 31.

[10] Id.

[11] 987 F.3d 1080, 1087 (Fed. Cir. 2021).

[12] Id. at 1088 (internal quotations omitted).

[13] 941 F.3d 1149, 1155–56, 1162 (Fed. Cir. 2019)

[14] 720 F.3d 1380, 1385–86 (Fed. Cir. 2013).

[15] F.3d 1340, 1346–47 (Fed. Cir. 2019).

[16] Memorandum Op., at 37.

[17] Memorandum Op., supra note 1, at 38-42.

[18] Id. at 42.

[19] Id.

[20] Id. at 45.

[21] Id. at 45.

[22] Id.

[23] Id. at 47 (internal citations omitted).

[24] Id. at 7.