Vifor (Int’l) AG v. Mylan Labs. Ltd.

Injectafer® (ferric carboxymaltose injection)

April 26, 2021

GENERICally Speaking: A Hatch Waxman Litigation Bulletin

Case Name: Vifor (Int’l) AG v. Mylan Labs. Ltd., No. 19-13955 (FLW), 2021 WL 1608908 (D.N.J. Apr. 26, 2021) (Wolfson, J.)

Drug Product and Patent(s)-in-Suit: Injectafer® (ferric carboxymaltose injection); U.S. Patent No. 10,519,252 (“the ’252 patent”)

Nature of the Case and Issue(s) Presented: Defendants Mylan and Sandoz filed an ANDA with FDA to market generic Injectafer, an iron-replacement product suggested for the treatment of iron-deficiency anemia (“IDA”) in adults. IDA was a condition that developed when stores of iron in the body dropped too low to support normal red- blood-cell production. Vifor sued defendants. On Oct. 9, 2020, ViIfor filed a motion for judicial correction related to claim 1 of the ’252 patent, which disclosed and claimed iron (III) carboxymaltodextrin complexes and the use of these complexes to treat IDA. As currently configured, claim 1 of the ’252 patent stated:

1. An iron (III) carboxymaltodextrin complex wherein said iron (III) carboxymaltodextrin complex comprises polynuclear iron (III) hydroxide 4(R)-(poly-(1-4)-O-α-Dglucopyranosyl)-oxy-2(R),3(S),5(R),6-tetrahydroxyhexanoate and has a weight average molecular weight in the range of from 80 kDa to 400 kDa, and wherein said 4(R)-(poly-(1-4)-O-α-D-glucopyranosyl)-oxy-2(R),3(S),5(R),6-tetrahydroxyhexanoate is derived from the oxidation of maltodextrin ....

Vifor contended that claim 1 contains an obvious error and that the prosecution history supported judicial correction. Specifically, Vifor argued that the “obvious” error related to the stereochemistry at carbon-3 of the hexanoate unit, which is incorrectly written as “3(S),” rather than “3(R).” The court, however, found that the alleged error was not clear and obvious from the face of the patent and did not exercise judicial correction.

Why Defendants Prevailed: Vifor contended that a POSA would recognize that the chemical name of the carbohydrate derived from the oxidation of maltodextrin recited in claim 1 of the ’252 patent contained an obvious error in stereochemical nomenclature. Put simply, a POSA would have clearly recognized that the stereochemistry designation at carbon-3 of the hexanoate was mistakenly written as (S), when it should be (R) based on the bonds. In addition, a POSA would have also recognized that the chemical name of the iron (III) carboxymaltodextrin complex recited in claim 1 of the ’252 patent contains this same obvious error in stereochemical nomenclature. Defendants responded that nothing in the language of the claim would signal to a POSA that there was an error, or absent “any red flag in the claimed chemical name or surrounding claim language, the POSA would have no reason to draw the chemical structure or perform a detailed stereochemistry analysis” like the one performed by Vifor’s expert. Relying on precedent where courts previously found it appropriate to exercise judicial correction, the court found the facts here “conspicuously distinguishable.” Those cases involved typographical errors of such an obvious nature that the claim at issue was either unintelligible, or the meaning was known to a POSA. Here, in order to uncover the error claimed by Plaintiffs, a POSA could not merely look at the claim language, or the specification, but rather must have conducted a stereochemistry analysis that included a tedious, multi-step analysis requiring the manipulation of three-dimensional molecular structures. While an error may have existed, it was not clear and “this Court should not be called on to provide the requested correction.”

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