Patent Term Extension Only Applies to Approved Product

By on May 7, 2020
Posted In Patents

In a case relating to a patented method for treating multiple sclerosis, the US Court of Appeals for the Federal Circuit found that patent term extension (PTE) only applies to methods of using the approved product as defined under the relevant statute, 35 U.S.C. § 156, even if the patent claim is broad enough to cover methods of using additional compounds. Biogen International GMBH v. Banner Life Sciences LLC, Case No. 20-1373 (Fed. Cir. Apr. 20, 2020) (Lourie, J.).

Biogen holds the New Drug Application (NDA) for the active ingredient dimethyl fumarate (DMF) which has been approved for the treatment of multiple sclerosis. Upon administration to a patient, DMF is metabolized into a second compound, monomethyl fumarate (MMF). The compounds are virtually identical except that DMF has two methyl (CH3) groups (red in the below diagrams) and MMF has only one. The two compounds also have the same “active moiety.”

Biogen owns a patent directed to a method of treating multiple sclerosis with either DMF or MMF. The patent was set to expire on April 1, 2018, but received a patent term extension of 811 days under §156.

In 2018, Banner filed an Abbreviated New Drug Application (ANDA) to market an MMF pill for the treatment of multiple sclerosis, relying on Biogen’s NDA for DMF to satisfy the safety and efficacy requirements. Biogen subsequently filed a Hatch-Waxman suit against Banner. Banner immediately moved for judgment of noninfringement, arguing that §156(b)(2) limits the scope of the patent extension to methods of using the approved product only. Banner further argued that because MMF was not the active ingredient in Biogen’s approved product, the PTE does not apply to use of MMF, even though the claims may be broad enough to cover MMF. The district court agreed and dismissed the case. Biogen appealed.

The Federal Circuit affirmed the district court’s dismissal. The Court noted that MMF did not fall within the scope of PTE because it was not the approved product. Under §156, an NDA holder is entitled to extend the term of only one patent for the corresponding approved product. The Court noted that “[c]ritically, for the purposes of this appeal, subsection (f) defines ‘product’ as ‘the active ingredient of . . . a new drug . . . including any salt or ester of the active ingredient.” §156(f)(2)(A). “Active Ingredient” is a term of art, defined by the FDA as “any component that is intended to furnish pharmacological activity or other direct effect,” and it “must be present in the drug product when administered.” Here, Biogen’s asserted patent claim could not cover MMF during PTE because (i) the active ingredient was DMF, not MMF and (ii) MMF was not a salt or ester of DMF. The fact that the two compounds shared the same active moiety, or that DMF was metabolized to MMF, did not cause MMF to fall within the definition of “Active Ingredient.”

The Federal Circuit also found that Biogen could not assert infringement under a doctrine of equivalents theory, noting that judge-made law cannot prevail over statute, and therefore, a product or process cannot logically infringe an extended patent claim under equivalence if it is not statutorily included in the extension under §156. Thus, despite the fact that DMF and MMF were similar enough, since Banner was able to rely on Biogen’s DMF safety and efficacy data in order to get its MMF pill approved, Biogen was precluded from asserting its extended claims against Banner’s MMF pill under §156.

Tags: Patents
Amy Mahan, PhDAmy Mahan, PhD
Amy Mahan focuses her practice on intellectual property matters in the life sciences, pharmaceutical and biotechnology sectors. She works on a variety of patent infringement litigation cases involving monoclonal antibody biologics, cell-based immunotherapies and small molecule drugs. Read Amy Mahan's full bio. 

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