In October, a Federal Circuit panel vacated a permanent injunction against Sanofi and Regeneron’s Praluent® and remanded the proceeding to the district court for a new trial on the defendants’ written description and enablement defenses.[i] The panel had held that the district court erred by (i) excluding the defendants’ evidence of written description and enablement, and (ii) improperly instructing the jury on written description.

On Wednesday, November 6, 2017, Amgen filed a petition for rehearing en banc by the entire Federal Circuit for consideration of the written description and enablement issues.[ii] Amgen asserted two grounds for rehearing in its petition.

First, Amgen argued the panel decision abrogated the “newly-characterized antigen” test, which, over the past 15 years, the Federal Circuit has recognized in multiple decisions as the test for compliance with the written description requirement. According to Amgen’s petition, the “newly characterized antigen” test states that “written description for ‘an antibody to [a] novel protein’ is satisfied ‘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.’ ”[iii] Amgen asserts the panel erred in dismissing the Federal Circuit’s prior cases as “dictum” because the “cases apply the test as the ratio decidendi[,] … the opposite of dictum.”[iv] This issue is exceptionally important, Amgen argues, as the “PTO has issued myriad patents under the newly-characterized-antigen test.”[v] Innovators will not invest in developing therapeutic agents “absent confidence they can take [the Federal Circuit’s] precedents at their word, especially in an industry where the few successful medicines must also fund the many research dead ends.”[vi] The panel decision overturning the ratio decidendi of three cases as “dictum,” Amgen asserts, gravely undermines that confidence.[vii]

Second, Amgen argues that the panel erred by holding that later-created embodiments are relevant to whether a patentee meets the written description requirement by disclosing representative species, upending “four decades of precedent holding post-priority-date embodiments irrelevant to patent validity.”[viii] Amgen contends that the Federal Circuit has held for decades that advances in the art after the priority date, such as new embodiments, are irrelevant to validity.[ix] According to Amgen, the panel agreed “that evidence of later-discovered embodiments is generally irrelevant,” but “nonetheless held that post-priority-date embodiments are relevant to whether a ‘patent fails to disclose a representative number of species.’ ”[x] Amgen contends the ruling will lead to dire consequences for both antibody innovation and PTO examinations because patent prosecutors will need to disclose embodiments developed after the priority date continually as they are discovered in order to avoid claims of inequitable conduct.[xi] As a result, inventors will have little reason “to invest billions of dollars to address unknown and difficult targets … if easier, subsequent developments—enabled by the patentee’s own disclosures—can be the basis for invalidating the patent that made them possible[.]”[xii] Amgen asserts this decision by the panel creates a “zone of uncertainty” since validity has hinged on the priority date for decades.[xiii]

Stay tuned to BiosimilarsIP for future updates in the case.


[i] Amgen Inc. v. Sanofi, 872 F.3d 1367 (Fed. Cir. 2017).

[ii] Amgen’s Petition for Rehearing En Banc, Amgen Inc. v. Sanofi, 872 F.3d 1367 (Fed. Cir. 2017) (No. 17-1480).

[iii] Id. at 13 (citing Centocor Ortho Biotech, Inc. v. Abbott Labs., 636 F.3d 1341, 1351-52 (Fed. Cir. 2011)).

[iv] Id. at 9.

[v] Id. at 17.

[vi] Id. at 18.

[vii] Id.

[viii] Id. at 10.

[ix] Id. at 19-20 (citing In re Hogan, 559 F.2d 595, 605 (C.C.P.A. 1977); U.S. Steel Corp. v. Phillips Petroleum Co., 865 F.2d 1247, 1251-52 (Fed. Cir. 1989); In re Koller, 613 F.2d 819, 823-24 (C.C.P.A. 1980)).

[x] Id. at 21 (citing Amgen, 872 F.3d at 1374–75).

[xi] Id. at 10-11.

[xii] Id. at 24.

[xiii] Id. at 25, 27