Rehearing En Banc Denied Over Three Dissenters in Biogen Written Description Case

By Cook Alciati | March 23, 2022

Today we launch the Gardella Grace IP Insights Blog.  The blog will focus on all things intellectual property with a focus on patents and patent litigation.  The blog will feature summaries and analysis of interesting decisions from the district courts, Federal Circuit, TTAB, PTAB, and other Circuit Courts of Appeals.  We hope you will follow along. 


Our first post builds on a recent webinar (available here) the firm conducted on March 15 titled:  In Possession of an Invention? Litigation Insights for Life Sciences Patent Drafting.  During that webinar, we presented on the Federal Circuit’s decision in Biogen International GMBH v. Mylan Pharmaceuticals Inc., 18 F.4th 1333 (Fed. Cir. 2022).  In Biogen, the Federal Circuit affirmed a district court finding, following a bench trial, that the asserted claims were invalid for lack of written description support.  The Court found that the claimed dosage rate was not adequately described as a “therapeutically effective” dosage for the treatment of multiple sclerosis.  Judge O’Malley dissented from the original decision, suggesting that the district court required written description support for a clinically effective dosage, rather than the claimed “therapeutically effective dosage.”  See id. at 1347-48.


Biogen sought panel and en banc rehearing.  As is common, the Federal Circuit denied both panel and en banc rehearing.  But less common was a dissenting opinion signed onto by Judges Lourie, Moore, and Newman.  A copy of the dissenting opinion is available here.  (Judge O’Malley retired and participated only in the panel rehearing—not the en banc determination).  The dissent briefly reviewed the history of the written description requirement and associated precedent and noted (at 3) that “in all that history, this case, in which every claim limitation is expressly described in the disclosure of the patent specification, is at the farthest end of the spectrum of cases where written description has not been found.  It is an outlier.”  According to the dissent, “by denying rehearing en banc, the judges of this court have let a panel majority opinion stand that imports extraneous considerations into the written description” and in “doing so, the court has contributed to the muddying of the written description requirement.”  Id.  The dissent identified four separate errors, each of which raises interesting questions concerning the written description requirement.


The boundaries of the written description requirement have proved elusive to practitioners for years.  The dissent seems to think that Biogen will further complicate matters.  We’d expect the fact of a lengthy and substantive dissent to encourage a petition to the Supreme Court.  Among the questions to watch for are whether 35 U.S.C. § 112 includes a written description requirement that is separate from the enablement requirement.  While the Federal Circuit has found such a requirement to be expressly in the statute in the en banc Ariad decision, the Supreme Court has not weighed in on that issue.  Stay tuned.