AstraZeneca aims to stifle Mylan’s revived shot at generic inhaler
AstraZeneca has urged the US Court of Appeals for the Federal Circuit to revisit a split panel decision that breathed new life into Mylan’s bid to produce a generic version of the asthma inhaler, Symbicort Turbohaler.
The pharmaceutical company filed the petition on January 21, arguing that this appeal requires an answer to one or more precedent-setting questions of exceptional importance.
The principle question according to AstraZeneca is: “whether the established, agreed-upon ordinary meaning of a numerical term in a claim may be displaced, in the absence of lexicography or disclaimer, on the basis that it may encompass more than the most preferred disclosed embodiment.”
The row erupted in 2018 when the pharmaceutical company sued Mylan (now part of Viatris) and 3M Company asserting infringement of a trio of patents, US numbers 7,759,328, 8,143,239 and 8,575,137 covering the blockbuster product.
The patents describe and claim a suspension composition in a pressurised metered dose inhaler for the treatment of asthma and other respiratory diseases.
In July 2020, Kindeva was added as a defendant in the action, while 3M was voluntarily dismissed from the case.
AstraZeneca has disclosed that Symbicort generated about $2.7 billion in revenue for the company in 2020, second only to Tagrisso, a medication used in the treatment of non-small-cell lung carcinomas.
The company met with initial success in its dispute with Mylan and Kindeva when the US District Court for the Northern District of West Virginia rejected the generic drug makers’ arguments that the patents-in-suit were invalid.
But on appeal in December, US Circuit judges Kara Stoll and Todd Hughes surmised that the case was a “close call” but that the lower court had misinterpreted part of the patent that requires the patented drug formulation to include 0.001% of a stabilising ingredient.
AstraZeneca had argued that the number could be between 0.0005% and 0.0014%, while Mylan and Kindeva held it should be closer to the exact percentage.
According to Stoll, the patent's written description and prosecution history showed that “very minor differences” in the ingredient's concentration would affect the drug's stability, upholding the generics’ view that the invention required a precise amount.
But the decision was a fractured one, as Judge Richard Taranto dissented from the majority's interpretation of the term.
“On its merits, this construction should be rejected, for the simplest of claim-construction reasons. Adopting this construction requires rewriting the claim term. And that rewriting is counter to the specification and prosecution history,” he wrote.
In its petition filed this month, AstraZeneca argued that the panel majority overlooked and misapprehended, by failing to cite or apply case law in “holding that the ordinary meaning of a numerical claim term based on significant digits may be displaced, in the absence of lexicography or disclaimer, because it may encompass more than the most preferred embodiment”.
The case is AstraZeneca v Mylan Pharmaceuticals, US Court of Appeals for the Federal Circuit, No. 21-1729.
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