UPDATE 1-US court finds Bayer contraceptive patent claim invalid
April 16, 2013 at 15:10 PM EDT
WASHINGTON, April 16 (Reuters) - A U.S. appeals court has ruled against Bayer AG, a world leader in oral contraceptives, reversing a ruling by a lower court and finding that parts of a patent for the German drugmaker's Yaz birth control pill were invalid.