KV Pharma Files Citizen Petition Requesting Relisting of Astra Zeneca's Toprol XL Patent
KV Pharmaceutical Company recently filed a citizen petition asking the FDA to relist U.S. Patent No. 5,246,714 for 100 mg and 200 mg Toprol XL in the Orange Book. In the same petition, KV asked the FDA to refrain from approving any ANDA for 100 mg and 200 mg Toprol XL filed after KV's ANDA No. 76-640 and to confirm that KV's right to 180 days of exclusivity based on its ANDA has not been affected by FDA's delisting of the '714 patent. Toprol XL is Astra Zeneca's extended release formulation of metoprolol succinate, a beta blocker approved for treating hypertension, angina, and heart failure. Sales of Toprol XL reached $1.3 billion last year.
According to KV's petition, its ANDA included paragraph IV certifications for each of the five patents listed in the Orange Book for Toprol XL: the '714 patent and U.S. Patent Nos. 4,927,640; 4,957,745; 5,001,161; and 5,081,154. While Astra brought suit in the Eastern District of Missouri based on KV's certifications with respect to the '154, '161, and '745 patents, it did not bring suit based on the '714 and '640 patent certifications. KV subsequently filed declaratory judgment counterclaims of non-infringement with respect to the '640 and '714 patents, which apparently have been dismissed in view of Astra's covenant not to sue on the patents.
KV argues in its citizen petition that FDA's delisting of the '714 patent was in error because delisting occurred after (1) KV filed its paragraph IV certification, and (2) the '714 patent had been subject to a lawsuit. Based on its belief that it was the first ANDA applicant to file a paragraph IV certification on the '714 patent, KV further argues that it is entitled to 180 days of marketing exclusivity for generic Toprol XL. KV's petition relies extensively on the recent Ranbaxy v. Leavitt case from the U.S. District Court for the District of Columbia, in which Ivax and Ranbaxy successfully appealed FDA's delisting of Merck's Zocor patents.
Previously, Astra sued KV, Andrx Pharmaceuticals, and Eon Laboratories based on ANDA filings for Toprol XL generics. The suits were consolidated, and in a ruling last January from the U.S. District Court for the Eastern District of Missouri, both patents were held invalid for double patenting and anticipation, and Astra was found to have engaged in inequitable conduct during prosecution of the patents. Astra has appealed the decision to the Federal Circuit.
NOTE: thanks to Kurt Karst for sending us a copy of the citizen petition.
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