In a recent decision, the issue before the Federal Circuit was the meaning of the term “product” in a patent term extension statute. Biogen Int'l GmbH v. Banner Life Scis. LLC, 956 F.3d 1351 (Fed. Cir. 2020). Section 156 of the Patent Act permits patent term extensions for FDCA-regulated products. 35 U.S.C. 156 (Hatch-Waxman Act). While awaiting FDA approval, the patent holder may not commercialize the product, and thus loses a part of the patent term. “The Hatch-Waxman Act provided for patent term extensions in §156 to partially compensate NDA applications for this loss of patent life.” Biogen, 956 F.3d at 1355.

Under the provisions of Section 156, Biogen International GmgH (“Biogen”) obtained an extension on its patent ‘001 for the treatment of multiple sclerosis using dimethyl fumarate (“DMF”) and monomethyl fumarate (“MMF”). Biogen’s prescription product DMF (Tecfidera®) was approved by the FDA in 2013 for the treatment of multiple sclerosis relapse. Biogen’s ‘001 patent term was extended to June 20, 2020 (by 811 days) to compensate for the period during which the Tecfidera® NDA application was pending.

Before the expiration of Biogen’s patent extension, Banner Life Sciences LLC (“Banner”) submitted a paper NDA application under 21 U.S.C. 355(b)(2), with clinical data supporting bioequivalence of its MMF drug product to Biogen’s DMF product Tecfidera®.

Biogen brought a patent infringement action against Banner in the District of Delaware, and Banner moved for a judgment of noninfringement. The District Court held for Banner. Reviewing closely the language of Section 156, the Federal Circuit affirmed, finding that the patent term extension applied to DMF only.

The Federal Circuit found that while patent ‘001 covers both DMF and MMF, only DMF is covered by the extension. Section 156 limits the scope of the extension to “any use approved for the product” and defines “product” as “the active ingredient of … a new drug … including any salt or ester of the active ingredient.” The active ingredient of Tecfidera® is DMF. MMF is an active metabolite of DMF. The difference between the two molecular structures is one ester group (in MMF) versus two ester groups (in DMF). The court noted that MMF is not an ester of DMF, but rather a de-esterified version of DMF. Section 156 “does not encompass a metabolite of the active ingredient or its de-esterified form.” Biogen, 956 F.3d at 1357. Thus the only “product” covered by the extension is DMF (Tecfidera®).