The World Anti-Doping Agency has dropped a defamation lawsuit against its American counterpart, a major retreat for the agency after nearly a year of escalating conflict over its handling of positive tests for a banned drug by 23 elite Chinese swimmers.
The decision by the agency — known by its acronym, WADA — to drop the suit it had filed in a Swiss court came months after it angrily reacted to comments from Travis T. Tygart, the leader of the U.S. Anti-Doping Agency. Mr. Tygart accused WADA of covering up the tests after The New York Times revealed details of how swimmers in China were found to have had a banned heart drug in their systems at a competition just months before the Tokyo Olympics.