Biogen v. Banner Life Sciences -- The Limited Scope Of U.S. Patent Term Extensions (Hint: Metabolites Not Included)

May 12, 2020 – Article

Under 35 U.S.C. §156, a patentee can extend a patent’s term to restore part of the term consumed during the Food and Drug Administration’s (FDA) New Drug Application (NDA) approval process for a compound covered by the patent.

Last month, in Biogen v. Banner Life Sciences, the Federal Circuit ruled that such an FDA-related patent term extension does not cover a metabolite of the FDA-approved compound. Rather, an extension covers only the approved compound itself, or a salt or ester thereof.

Biogen involved the product Tecfidera®, in which the active ingredient is dimethyl fumarate (DMF).  Upon administration, one of DMF’s methyl ester groups is metabolized to yield  monomethyl fumarate (MMF) before reaching its pharmacological site of action.

Biogen’s patent, U.S. 7,619,001 (’001 patent), contained claims covering both DMF and its MMF metabolite.  The ’001 patent was slated to expire on April 1, 2018, but Biogen extended its term by 811 days under Section 156 to compensate Biogen for loss of patent term during the FDA’s review of Tecfidera®.  The ’001 patent now expires on June 20, 2020.  The issue in Biogen was whether Biogen’s patent term extension covered the MMF metabolite.   

Banner submitted a 505(b)(2) application to market a drug product containing MMF.  In support of its application, Banner relied upon clinical data that Biogen submitted to the FDA in its Tecfidera® NDA to satisfy safety and efficacy requirements.

Among other arguments, Biogen asserted that Section 156’s extension applies to any compound that shares an “active moiety” with the approved compound and that because DMF and MMF share an active moiety (MMF), Banner’s proposed product infringes the extended ’001 patent.  Biogen also argued that this is particularly true given Banner’s reliance on Tecfidera®’s clinical data.

The Federal Circuit ruled against Biogen, stating that Section 156 extensions cover the active ingredient itself (or a salt or ester thereof).  They do not cover an “active moiety”:

It encompasses the active ingredient that exists in the product as administered  and as approved—as specified by the FDA and designated on the product’s label—or changes to that active ingredient which serve only to make it a salt or an ester. It does not encompass a metabolite of the active ingredient or its deesterified form.

MMF, although covered by the ’001 claims, was not covered by the Section 156 term extension.  So no infringement existed (the ’001 patent expired with respect to MMF).

The Federal Circuit also noted that no infringement under the doctrine of equivalents was possible, stating that “such a product or process cannot logically infringe an extended patent claim under equivalence if it is statutorily not included in the extension under § 156. That would make judge-made law prevail over statute.”

In view of Biogen, 505(b)(2) applications directed to metabolites of approved compounds are a viable option, particularly where a lengthy Section 156 term extension for the approved active ingredient has been granted.