Levomilnacipran – USA

Levomilnacipran – USA

Allergan Pharmaceuticals International Ltd et al v. Prinston Pharmaceutical Inc. et al

Case: No. 2:2017cv10230

Judge: Esther Salas

Date: 06/08/2021

Court: District of New Jersey – Claim construction

 

This case is related to plaintiffs (Allergan) drug product, Fetzima®, which is used to treat patients with major depressive disorder. Plaintiffs initially asserted three patents against defendants Aurobindo, MSN Lab, Torrent Pharma and Zydus. At issue for claim construction are two of the three asserted patents:  US 8,481,598 and US RE43, 879, both of which involve method of treatment claims regarding levomilnacipran and its derivatives.

 

Construction of disputed terms:

 

A. “about 120 mg/day of levomilnacipran or a pharmaceutically acceptable salt thereof”

Defendants’ proposed construction: “about 120 mg/day of levomilnacipran or about 120 ml/day of a pharmaceutically acceptable salt of levomilnacipran.”

Plaintiffs’ updated proposed construction: “[about] 120 mg/day of levomilnacipran or a molecular weight equivalent amount of a pharmaceutically acceptable salt of levomilnacipran.”

Court’s construction: “about 120 mg/day of levomilnacipran or a molecular weight equivalent amount of a pharmaceutically acceptable salt of levomilnacipran.”

Court’s analysis: The parties dispute whether the dosage limitation, 120 mg/day, modifies only the active moiety of the levomilnacipran salt, as Plaintiffs argue, or, instead, modifies the overall levomilnacipran salt compound, as Defendants argue. The Court agreed with Plaintiffs. Court said that based on the clear language of the specification, a person of ordinary skill in the art (“POSA”) would understand that the ’598 Patent does not discuss dosage amounts in a vacuum—the invention encompasses “methods of treatment using these dosage forms” to achieve
therapeutical effects on patients in need. The patent defines the terms “effective amount” and “therapeutically effective amount” as “an amount or quantity of levomilnacipran which is sufficient to elicit an appreciable biological response when administered to a patient.” In addition, throughout the specification, the ’598 Patent discusses the
invention in terms of “active ingredient.” Therefore, POSA would understand that “the strength of a drug is generally expressed in terms of the active moiety rather than its salt form.”

 

B. “relative to administration of racemic milnacipran hydrochloride”

Defendants’ proposed construction: “dependent on administering racemic milnacipran hydrochloride to the same patient.”

Plaintiffs’ updated proposed construction: “relative to the risks of cardiovascular disturbances and/or the risks of organ and/or tissue toxicity associated with administration of racemic milnacipran hydrochloride.”

Court’s construction: “relative to the risks of cardiovascular disturbances and/or the risks of organ and/or tissue toxicity associated with administration of racemic milnacipran hydrochloride.”

Court’s analysis: Milnacipran exists in the form of two optically active enantiomers: the dextrogyral enantiomer and the levogyral enantiomer. Plaintiffs argued the disputed term is included as “a comparator with respect to the then-known risks associated with racemic milnacipran,” and that the claims do not actually require administering racemic milnacipran hydrochloride to the same patient who is administered levomilnacipran hydrochloride. Defendants argued that the claims require that both levomilnacipran hydrochloride and racemic milnacipran hydrochloride be administered to the same patient, so as to assess and compare the risks associated with the two drugs. The Court again agreed with Plaintiff and said that this construction is compelled by the claims and specification of the ’879 Patent. The plain language of the claim reads as a single-step method: “[a] method for treating a patient . . . comprising the step of administering” levomilnacipran hydrochloride. ’879 Patent, Claim 1. The word “step” in the claim is singular, not plural. Thus, contrary to Defendants’ argument, the claims cannot be read as requiring an additional step of administering milnacipran hydrochloride or an additional step of evaluating and comparing the recited risks associated with milnacipran hydrochloride and milnacipran hydrochloride incurred by the same patient. In addition, nowhere does the specification describe actual administration of racemic milnacipran hydrochloride to the same patient who is also administered levomilnacipran hydrochloride.

 

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