This affirms a previous ruling in Zeneca's favour by the U.S. District Court for the District of Maryland in April 1996. Novopharm's case has now been effectively disposed of, validating Zeneca's decision to enforce its U.S. patent, which is effective until 2002.
Tamoxifen is the most widely used medicine for the treatment of breast cancer.
It was an original invention of ICI Pharmaceuticals. The U.S. patent is now owned by Zeneca. Zeneca began patent infringement proceedings against the Canadian generic drug company, Novopharm, in January 1995. Under U.S. law, the filing of an ANDA is an act of patent infringement, and Zeneca accordingly instituted patent infringement proceedings. In April 1996, after a full trial, the U.S. District Court in Maryland held that Zeneca's U.S. tamoxifen patent is valid, enforceable and would be infringed by any sale of tamoxifen citrate in the United States by Novopharm.