Teva loses appeal to invalidate Korlym patent
Teva Pharmaceuticals has failed to convince the US Court of Appeal for the Federal Circuit that a Corcept Therapeutics method patent for Korlym (mifepristone) was invalid.
The Israeli pharma giant sought to overturn a Patent Trial and Appeal Board (PTAB) ruling that dismissed its challenge to Corcept’s patent for using Korlym to treat Cushing’s syndrome, claiming that the board had misapplied obviousness law.
In a judgment handed down Tuesday, December 7, the Federal Circuit sided with the board, affirming the decision entirely.
Corcept had sued Teva in 2018, alleging that Teva’s proposed generic of Korlym infringed Corcepts’ US Patent 10,195,214.
The patent is directed to methods of treating Cushing’s syndrome by co-administrating mifepristone and a CYP3A inhibitor in order to produce excess cortisol.
Teva sought a post-grant review of claims 1-13 of the patent, claiming that the patent was obvious and that it was “reasonably likely” to a skilled artisan that the co-administration of the drugs would be effective in treating the syndrome.
The board ruled in favour of Corcept last year, saying that Teva had failed to prove that the claims were obvious. It also discredited the likeliness argument, finding it inconsistent with later testimony and other evidence.
On appeal, Teva argued that the PTAB had an “improperly” precise standard for proving the invalidity of the patent.
However, the Federal Circuit found that the board did not err in its requirements and rejected Teva’s argument that prior art disclosed a range of potential doses that would cover Corcept’s patent.
It also agreed with the PTAB that the likeliness argument was inconsistent by first claiming that it was “reasonably likely” that the drug co-administration would be effective, and later claiming that a skilled artisan would have “no expectation” as to whether the co-administration would be safe.
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