Fed Circuit sides with Merck in antifungal treatment dispute
A US court has upheld a decision that eight claims of one of Mayne Pharma’s patents are unpatentable for obviousness over prior art after a validity challenge was brought by a subsidiary of Merck & Co.
In a decision on Friday, June 21, the US Court of Appeals for the Federal Circuit affirmed a ruling by the US Patent and Trademark Office, that the inter partes review was not time-barred.
The ruling comes after the US Supreme Court said yesterday, June 24 that it would hear a case on a similar issue in Dex Media Inc v Click-To-Call Technologies.
The court will decide whether the Federal Circuit has the power to review Patent Trial and Appeal Board decisions regarding the timeliness of patent challenges.
The patent in dispute (US number 6,881,745) covers pharmaceutical compositions of azole antifungal drugs that are insoluble in aqueous solution.
The case dates to 2015, when Mayne filed a complaint against Merck Sharp & Dohme, alleging that Merck’s Noxafil (posaconazole) treatment for fungal infections infringed its patent.
In 2016, Merck filed a request for an inter partes review of the patent at the USPTO, arguing that the claims of the patent were obvious and anticipated over three earlier patents.
Under US law, an inter partes review may not be instituted if the petitioner was served with a patent infringement claim more than a year before the review was requested.
Mayne had argued that because Merck’s parent company, Merck & Co, was added to the case as a party of interest well after the one-year deadline, the inter partes review was time-barred.
But, the Federal Circuit ruled that MCI’s addition did not alter the filing date.
Additionally, the Federal Circuit agreed with the USPTO that the claims would have been obvious to a person skilled in the art in view of the earlier patents.
Mayne had also argued that the USPTO erred in failing to limit the usage of the drug to humans.
It said “a person of ordinary skill would immediately understand … that the claims of the ’745 patent are directed to humans only”.
But the Federal Circuit agreed with Merck and said the broadest interpretation of the claims is not limited to humans.
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