Pfizer's (PFE -0.2%) Viagra patent has been ruled no longer valid by Canada's top court, backing...

|About: Pfizer Inc. (PFE)|By:, SA News Editor

Pfizer's (PFE -0.2%) Viagra patent has been ruled no longer valid by Canada's top court, backing an appeal by generic drug maker Teva Pharmaceutical (TEVA +0.1%) that claimed PFE hadn't provided sufficient details when it initially filed its patent registration.