Federal Circuit Revives Escitalopram Patent Suit

An appeals court has revived Caraco Pharmaceutical Laboratories Ltd.'s declaratory judgment suit against Forest Laboratories Inc. over a patent for depression drug Lexapro despite a covenant by Forest not to sue its generics-making rival over the patent. The U.S. Court of Appeals for the Federal Circuit reversed and remanded the case back to the U.S. District Court for the Eastern District of Michigan, which had dismissed Caraco's request for a declaratory judgment of noninfringement. The appeals court said there was no record the lower court considered two cases establishing the legal precedents to be taken into account in such a patent dispute. Following patents are listed in Orange Book
USRE34712 (Expiry: MAR 14, 2012)- which covers compound selected from substantially pure (+)-1-(3-Dimethylaminopropyl)-1-(4'- fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile and non-toxic acid addition salts thereof.
US6916941(Expiry: FEB 12, 2023)- which covers crystalline particles of escitalopram oxalate having a median particle size of at least 40 .mu.m.
Ivax (Now part of Teva) was the first Para IV applicant on this product. Accordingly, Ivax is entitled to 180 days of market exclusivity, which will begin either on the day it begins marketing its drug or on the day a court determines that both the '712 and '941 patents are invalid or not infringed, whichever comes first. However Forest sue Ivax on 712 patent infringement, which was found valid and infringed by the district court.
Caraco (Sun Pharma) filed para IV against both O.B listed patents. Innovator sued Caraco for the infringement of 712’ patent. Caraco then filed a complaint seeking a declaratory judgment that its generic version of Lexapro does not infringe the '941 patent. Forest granted Caraco an irrevocable covenant not to sue for infringement of the '941 patent. Due to the covenant not to sue, the district court dismissed Caraco's complaint for lack of jurisdiction.
The Federal Circuit decided (opinion) that an ANDA applicant's declaratory judgment action for noninfringement meets Article III's "case or controversy" requirement notwithstanding that the patentee has granted the applicant a covenant not to sue. The Federal Circuit further determined that the issues are ripe and the case is not moot. Accordingly, the court held that Caraco's action presents an ongoing Article III case and controversy, reversed the district court's decision dismissing the case, and remanded the case for a decision on the merits.
more details on orangebookblog