The highly-anticipated rematch between Lamont Peterson and Amir Khan has been canceled after the American tested positive for a banned substance.
Peterson, the unified light welterweight titleholder, tested positive for synthetic testosterone following a random test in March. He had undergone testosterone therapy for low levels in November.
Golden Boy Promotions announced Wednesday that the fight, which was scheduled to take place May 19 in Las Vegas, was officially off.
Nevada Athletic Commission executive director Keith Kizer had earlier confirmed to USA Today that Peterson was not granted a boxing license and Britain's Khan also tweeted that there would be no bout.
"The fight is off! sorry everyone the only person to blame is @kingpete26 [Peterson]. I'll be looking for an opponent to fight June 30th."
In December, Peterson won the WBA and IBF light welterweight titles in a controversial split decision against Khan in his hometown of Washington, D.C.
Khan was docked points for pushing during the fight, and questions were raised about judge George Hill's scoring.
According to USA Today, Peterson is likely to be stripped of the titles and Golden Boy CEO Richard Schaefer said he hoped the organizations would "do the right thing" by declaring the December fight a no-contest and returning the belts to Khan.