Fed Circuit split decision denies Biogen’s bid to revive MS drug patent
The US Court of Appeals for the Federal Circuit has refused Biogen’s attempt to revive a key patent for its multiple sclerosis drug Tecfidera (dimethyl fumarate), leaving Mylan’s successful challenge intact.
In a split decision handed down on Tuesday, November 30, the Federal Circuit affirmed the US District Court for the Northern District of West Virginia’s finding that the asserted claims of US patent 8,399,514 were invalid.
Invalidation of the patent, which claims a method of treating multiple sclerosis with dimethyl fumarate, helped clear the path for Mylan to launch its own generic version of the drug.
Mylan launched its generic version of Biogen’s $4 billion-a-year drug Tecfidera in August last year, two months after Mylan succeeded in having the key patent invalidated. Originally, the patent was due to expire in 2028.
Earlier this week, the Federal Circuit concluded that the Virginian court “did not clearly err in determining that Mylan has established its burden of showing, by clear and convincing evidence, that the asserted ‘514 patent claims are invalid for lack of written description”.
Circuit Judge Jimmie Reyna, who delivered the opinion for the majority, held that a “single passing reference” in the patent specification to Biogen’s claimed method of using a specific dosage of dimethyl fumarate was not enough to inform a skilled artisan that the drug would be effective in treating multiple sclerosis.
“The written-description requirement limits patent protection only to individuals who perform the difficult work of producing a complete and final invention featuring all its claimed limitations and publicly disclose the fruits of that effort,” added Reyna.
He concluded that the “record shows that the inventors were not in possession of a method of administering a therapeutically effective dose” of dimethyl fumarate to treat multiple sclerosis on or before the February 8, 2007 priority date.
Judge O’Malley’s dissent
In dissent, Circuit Judge Kathleen O’Malley said: “While I am loath to reverse district court determinations that rely heavily on credibility findings, I must respectfully dissent.”
O’Malley concluded that the district court had erred in finding that Biogen was judicially estopped from drawing a distinction between clinical and therapeutic effects, leading the district court to legally err in its interpretation of Federal Circuit written description precedent.
According to O’Malley, the Virginian court had incorrectly focused on the patent's failure to describe the treatment's "clinical efficacy”, rather than its therapeutic effects which “do not require efficacy on clinical endpoints or superior efficacy to existing drugs”.
"In my view, the district court’s refusal to acknowledge the difference between therapeutic and clinical effects evinces a fundamental misunderstanding of what is claimed—and, thus, what requires written description support—in the ‘514 patent,” she said.
O’Malley added: “Because I believe the entire course of the district court’s analysis might well change if the court were to adjust the lens through which it considers the evidence and testimony, I would remand for reconsideration of the record with the understanding that the patent is not about clinical efficacy—it is about therapeutic effect—and that the written description and obviousness inquiries are not the same.”
