Federal Circuit partly affirms injunction in Mylan’s favour
The US Court of Appeals for the Federal Circuit partly affirmed a preliminary injunction against India-based Aurobindo Pharma last week.
On Friday, May 19, the court handed down its decision, granting Mylan injunctive relief for one patent and holding that a district court had erred in granting an injunction for two other patents.
Mylan is the exclusive licensee of US patent numbers 7,622,992, 8,969,616 and 9,353,050, which relate to isosulfan blue (ISB), a dye used to map lymph nodes.
Apicore, a manufacturer of active pharmaceutical ingredients, is the owner of the patents.
Patents ‘992 and ‘616 are directed to a process for preparing ISB, while ‘050 is directed to an ISB compound having a purity greater than 99%, as measured by high performance liquid chromatography (HPLC).
HPLC is a form of column chromatography that pumps a sample mixture or analyte in a solvent at high pressure through a column with chromatographic packing, according to the Linde Group, a supplier of gases.
Apicore had focused on developing an “improved process for synthesising ISB” and in 2007 filed a patent application “that ultimately led” to the three patents.
The Food and Drug Administration (FDA) approved an Abbreviated New Drug Application filed by a subsidiary of Mylan in 2010. This application was based on a dye product that had previously been on the market.
In a separate development, Aurobindo sought FDA approval for a generic version of Mylan’s ISB product, informing the FDA that it had studied a “number of patents” describing ISB manufacture and selected Apicore’s ‘992 patent.
“Aurobindo acknowledged to the FDA that it was looking for a reagent ‘other than silver oxide’,” said the court, adding that the India-based company then chose manganese dioxide.
The company also used preparatory HPLC to achieve an ISB purity of greater than 99.5%.
Mylan then sued Aurobindo for infringement and sought a preliminary injunction, which the US District Court for the Eastern District of Texas granted.
“First, the district court evaluated the likelihood of success on the merits and found that Aurobindo likely infringed the process patents under the doctrine of equivalents,” said Circuit Judge Alan Lourie, on behalf of the court.
In its appeal, Aurobindo disputed this finding, arguing that it had “raised a substantial question of infringement of the process patents under the doctrine of equivalents because manganese dioxide oxidises isoleuco acid in a different way than silver oxide”.
The Federal Circuit said that the district court’s analysis of the process claims was “flawed by being unduly truncated”.
It added: “We conclude that the district court’s analysis of equivalence in this case was flawed, no doubt because of the sparse and confusing case law concerning equivalents, particularly the paucity of chemical equivalence case law, and the difficulty of applying the legal concepts to the facts.”
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