Mifepristone – USA

Mifepristone – USA

On Dec. 07, 2021, Federal Circuit affirmed PTAB and found method of use patent valid.

 

Corcept owns US 10,195,214 patent which relates to methods of treating Cushing’s syndrome when mifepristone is co-administered with strong CYP3A inhibitor such as Ketoconazole. Specifically, the dose of mifepristone is reduced to 600 mg when co-administered with strong CYP3A inhibitor, because of drug-drug interaction. Teva filed ANDA for Korlym (mifepristone) generic and Corcept sued Teva for infringement. Teva then sought post-grant review of claims 1 to 13 of US’214 patent. Teva argued those claims would have been obvious in light of Korlym’s label and Lee, optionally in combination with FDA guidance on drug-drug interaction studies. In its final-written decision, the Board held that Teva failed to show that a skilled artisan would have had a reasonable expectation of success for safe co-administration of more than 300 mg of mifepristone with a strong CYP3A inhibitor.

 

Teva appealed with respect to 2 points. First, Teva argued that the Board improperly required it “to show an expectation that the specific dose recited in the claims would have been safe.” Second, Teva argued that the Board committed legal error when it found Teva had failed to prove the general working conditions disclosed in the prior art encompassed the claimed invention

 

Federal Circuit found no clear error and affirmed the Board. With respect to first point, Federal Circuit said that claim 1 of the ’214 patent requires safe administration of a specific amount of mifepristone, 600 mg per day. (construing claims to require safe administration, rather than just administration). Thus, the Board was required to frame its reasonable-expectation-of-success analysis around that specific dosage of mifepristone. Court further said that “the evidence supported that [a skilled artisan] would have had no expectation as to whether co-administering dosages of mifepristone above the 300 mg/day threshold set forth in the Korlym label would be successful.” Because there was no expectation of success for any dosage over 300 mg per day, there was no expectation of success for the specific 600 mg per day dosage. With respect to second point, Federal Circuit said that substantial evidence supported the Board’s finding that the general working conditions disclosed in the prior art did not encompass the claimed invention, i.e., there was no overlap in ranges. In the Board’s view, “the evidence of record supported that the general working conditions limited co-administration of mifepristone with a strong CYP3A inhibitor to just 300 mg/day.” Therefore, a skilled artisan would have had no reasonable expectation of success for 600 mg per day dose.

 

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