Bases and Esters and Salts . . . Redux! Federal Circuit Affirms Non-Infringement Ruling Because PTE Statute Benefitting Ester Drug Does Not Cover De-Esterified Drug

Apr 22, 2020

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Biogen International GmbH obtained a patent for methods of treating multiple sclerosis using a fumarate diester (DMF) or fumarate monoester (MMF). Biogen developed and received Food and Drug Administration (FDA) approval in March 2013 for a DMF-based drug called Tecfidera®. No MMF is present in Tecfidera® DMF capsules, but the DMF in Tecfidera® is converted into MMF in the body and MMF produces a therapeutic effect. Biogen obtained 811 days of PTE under 35 U.S.C. § 156, thereby extending the expiration date of the patent from April 1, 2018, to June 20, 2020.

In January 2018, Banner Life Sciences LLC submitted a new drug application (NDA) for an MMF-based drug called Bafiertam, relying on Biogen’s clinical data for Tecfidera® to demonstrate safety and efficacy. In December 2018, Biogen sued Banner for patent infringement. Banner filed an answer and moved for judgment on the pleadings, arguing that as to MMF, Biogen’s patent had already expired and was therefore not infringed. On January 7, 2020, the district court ruled in Banner’s favor1; Biogen then sought expedited appellate review.

On appeal, Biogen argued that the district court misinterpreted Section 156(f) by excluding a de-esterified form an approved produce from its scope. According to Biogen, under Pfizer v. Dr. Reddy’s Laboratories, 359 F.3d 1361 (Fed. Cir. 2004), the term product in § 156(b) encompasses a de-esterfied form of an approved product because the “active ingredient” means the “active moiety” in the drug. Banner responded that the Federal Circuit’s rulings in Glaxo Operations UK Ltd. v. Quigg, 894 F.2d 392 (Fed. Cir. 1990), and PhotoCure ASA v. Kappos, 603 F.3d 1372 (Fed. Cir. 2010), expressly exclude the de-esterified form of the active ingredient, and that Biogen had misinterpreted Pfizer.

The Federal Circuit began its analysis by setting out § 156’s statutory scheme for PTE. Section 156(b) limits the extension to any use approved for the product, and product is defined in § 156(f) as the active ingredient of a new drug, including any salt or ester of the active ingredient. The court then rejected both sides’ arguments as to the applicability of the specific issues decided in Glaxo, Pfizer and PhotoCure, and instead held that a straightforward application of the statute controlled the outcome.

The court explained that Glaxo was inapplicable because that case addressed whether a separately patented ester compound could receive extension under § 156(a). The court in Glaxo held that the ester could get PTE because the ester was not the same product as the previously approved product within the meaning of § 156(f). The court noted that, as was explained in Glaxo, “product” is defined in § 156(f) not as the active moiety, but as the active ingredient or ester or salt of the same.

Here, the drug at issue, MMF, was not the approved product. However, MMF is neither the active ingredient in Tecfidera® nor an ester of DMF. Thus, MMF is not the same product as Tecfidera® under § 156(f) and does not fall within the scope of PTE under § 156(b).

The court further explained that Pfizer was inapposite. The court in Pfizer held that an extension for amlodipine covered the maleate salt of amlodipine because the active ingredient was the same under the statutory definition. Unlike the situation in Pfizer, MMF is not a salt of DMF. As to PhotoCure, the court explained that the case involved an analogous situation to Glaxo and therefore broke no new ground.

The Federal Circuit then rejected Biogen’s argument that the PTE for method of treatment patents under § 156(b)(2) was broader than that for composition patents under § 156(b)(1). Rather, the definition of product in the statute is the same for each subsection, and therefore the statute does not distinguish between a product and its use.

The court concluded its analysis by explaining that infringement under the doctrine of equivalents could not be used to sweep in a product that was statutorily not included in the scope of PTE.

Notably, the parties requested and obtained expedited review, receiving a decision within three months: the appeal was docketed on January 23, 2020; an unopposed motion for expedited briefing was filed on January 27 and ordered on February 21; and the court issued its judgment on April 21 without oral argument.

Practice Tip: Parties engaged in litigation involving NDAs should be cognizant of the possibility that data submitted for FDA-approval will not necessarily provide a patent term extension for products that are variants of the approved product.

Biogen Int’l GmbH v. Banner Life Scis. LLC, No. 2020-1373, 2020 WL 1920990 (Fed. Cir. Apr. 21, 2020) (Lourie, Moore, Chen)


1 A discussion of the district court’s decision can be found here: https://www.akingump.com/en/experience/practices/intellectual-property/ip-newsflash/bases-and-esters-and-salts-oh-my-limits-on-pte-benefits-provide.html.

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