Amgen Seeks En Banc Consideration of Written Description and Enablement Issues in Praluent® Litigation

by Goodwin

In October, a Federal Circuit panel vacated a permanent injunction (which the Federal Circuit had earlier stayed pending appeal) that would have otherwise prohibited the sale of Sanofi and Regeneron’s Praluent® (alirocumab) product and remanded the appeal to the district court for a new trial on the defendants’ written description and enablement defenses. The patents-in-suit are directed to monoclonal antibodies that inhibit PCSK9.  The claims define the antibodies, not by their structures, but by their function of binding certain residues of the PCSK9 antigen.  At trial, the defendants asserted, unsuccessfully, that these genus claims failed to comply with the written description and enablement requirements.  The Federal Circuit vacated the district court’s judgment as it related to written description and enablement because the district court had wrongly precluded the defendants from introducing evidence of post-priority-date embodiments of the claimed genus of antibodies to establish that the patent specification did not disclose a representative number of species of that genus.

Yesterday, Amgen filed a petition for rehearing en banc seeking consideration by the entire Federal Circuit of the written description and enablement issues.  Amgen asserts two primary grounds for rehearing, summarized below.

First, Amgen argues that the panel improperly abrogated the Federal Circuit’s “newly-characterized antigen” test for compliance with the written description requirement, as established by multiple Federal Circuit decisions over the past 15 years, and as applied by the USPTO in examining and issuing myriad patents “for longer still.” According to the petition, the “newly-characterized antigen” test provides that a claim to “an antibody to a novel protein” satisfies the written description requirement even “without describing the antibody when (1) the applicant fully discloses the novel protein and (2) generating the claimed antibody is so routine that possessing the protein places the applicant in possession of an antibody.”  Amgen asserts that the panel wrongly dismissed the discussions of the test in past Federal Circuit written description decisions as mere “dictum,” when the cases actually “apply the test as the ratio decidendi[,] … the opposite of dictum.”  The panel decision, Amgen contends, “gravely undermines th[e] confidence” of innovators of therapeutic agents that “they can take this Court’s precedents at their word, especially in an industry where the few successful medicines must also fund the many research dead-ends.”  Amgen further argues that “without genus claims,” like the ones at issue in its patents, “patent protection for antibodies would be nearly worthless” because “copyists” can make minor changes to the antibody sequence to “avoid infringement while still exploiting the benefits of Amgen’s invention.”

Second, Amgen asserts that the panel erred in vacating the district court judgment as to written description and enablement and remanding for a new trial at which Amgen will be permitted to present post-priority-date evidence in support of these defenses. According to Amgen, “[t]he panel decision upends four decades of precedent holding post-priority-date embodiments irrelevant to patent validity,” “hits the most groundbreaking inventions the hardest,” and “threatens to create a ‘zone of uncertainty’ that ‘discourages invention.’” Amgen contends that allowing consideration of post-priority-date embodiments in an invalidity analysis “makes no sense” because it could mean that “validity dissipates over time,” putting a patent “at greatest risk of invalidity just when it may be most valuable.”  Furthermore, Amgen asserts, the panel decision “portends serious problems for patent prosecution” because it could require “patent applicants … to disclose post-priority developments continuously as they arise” and upsets the rule that “the law [does] not require that an applicant describe in his specification every conceivable and possible future embodiment of his invention.”

No response may be filed to a petition for an en banc consideration unless the court orders a response. Stay tuned to Big Molecule Watch for further developments.

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