In re Metoprolol Succinate Patent Litigation

AstraZeneca AB, Aktiebolaget, Hassle, and AstraZeneca LP (collectively “Astra”) (plaintiffs) manufactured and marketed metoprolol succinate in “extended release” forms under the brand name Toprol-XL. Toprol-XL was used to treat angina, hypertension, and congestive heart failure. In 1971, an Astra inventor named Toivo Nitenberg in Sweden synthesized metoprolol succinate. In 1982, another Astra employee in Sweden named Lars Lilljequist also synthesized metoprolol succinate, possibly at the direction of two other Astra employees, Appelgren and Eskilsson. In 1983, Appelgren and Eskilsson left Astra to join Lejus Medical AB (“Lejus”). In January 1984, Lejus filed a patent application (‘197) for metoprolol succinate with the Swedish Patent Office, naming Appelgren and Eskilsson as inventors. Thereafter, Lejus filed a U.S. patent application for metoprolol succinate claiming priority from the Swedish patent application. After noticing Lejus’ U.S. patent application, Astra commenced a transfer of ownership action with the Swedish Patent Office asserting that Nitenberg was the inventor of metoprolol succinate. In the resulting settlement agreement between Astra and Lejus, the two companies agreed to divide claims to “metoprolol succinate” and to assign the divided claims to Astra. Appelgren and Eskilsson were listed as inventors of metoprolol succinate and Astra agreed that Lejus retained the rights to the ‘197 application that did not include the divided claims. In March 1988, Astra filed a U.S. patent application (‘897) which was a continuation, in part, of the Lejus ‘197 application. In January 1992, the Astra ‘897 application resulted in the issuance of the ‘154 patent with the only claim being “metoprolol succinate.” At the same time, Lejus was issued the ‘318 patent, resulting from the ‘197 application. Thereafter, Astra filed multiple suits for infringement in various district courts against three companies seeking to market generic versions of Toprol-XL. The actions were then consolidated into multidistrict patent infringement litigation. The three defendants filed a motion for summary judgment which was granted by the district court, holding that Astra’s ‘154 patent was invalid for double patenting. Astra appealed.