The much-anticipated rematch between Lamont Peterson and British boxer Amir Khan has been cancelled after the American failed a drug test, Golden Boy Promotions announced on Wednesday.
Peterson and Khan had been due to fight on May 19 in Las Vegas, after the American took the WBA and IBF light-welterweight titles in December in a controversial split decision.
But Golden Boy said Peterson's failed drug test - reports said he tested positive for synthetic testosterone - combined with the Nevada State Athletic Commission's inability to hold a hearing in time led to the fight's demise.
"A failed pre-fight drug test administered by the Voluntary Anti-Doping Association (VADA) coupled with the Nevada State Athletic Commission's legal inability to hold a formal hearing on the matter of licensing Lamont Peterson .... has forced the cancellation of the event," Golden Boy said in a statement.
Khan reacted strongly to the news, putting the blame squarely on Peterson's shoulders.
"The fight is off! sorry everyone the only person to blame is @kingpete26 I'll be looking for an opponent to fight June 30," he said on Twitter.
Both Khan and Peterson had agreed to random testing by VADA ahead of the rematch.
Peterson won their first bout in Washington in December by a score of 113-112 on two judges' scorecards while the other had Khan a 115-110 winner.
Following the fight, the British boxer - who won an Olympic silver as a 17-year-old in 2004 - claimed a "home-town decision" had robbed him of victory. The World Boxing Association ordered a rematch, saying it should take place within 180 days.
Referee Joe Cooper unfairly deducted two points off Khan's scores during the fight for excessive pushing, and also failed to give Khan credit for a knockdown in the first round, the WBA said.
Peterson's publicist Andre Johnson said in a statement to RingTV.com earlier in the week that the boxer's camp was mystified by the test results.
"We have tremendous respect for VADA and its mission. Lamont, Barry and the entire team emphatically support random drug testing in the most comprehensive manner possible," he said.
"We are working expeditiously with a team of pathologists and other medical specialists to confirm the origin of the test result and in full compliance with the rules of the Nevada State Athletic Commission.
"Lamont has never had a positive test either before or after this isolated occurrence."