Lamont Peterson reacts after defeating Amir Khan via split decision winning during their bout in December in Washington. (Patrick McDermott/GETTY IMAGES)

The rematch between Lamont Peterson and Amir Khan was called off after the Nevada Athletic Commission on Wednesday night declined to issue Peterson a license to fight in the state in the wake of his positive test for a banned substance.

Reports of the positive test, which took place in March, surfaced less than two weeks from the scheduled bout that had been set for May 19 in Las Vegas. Peterson, a District native, was to put his World Boxing Association super lightweight and International Boxing Federation junior welterweight belts on the line.

Representatives from both camps confirmed the cancellation, leaving in doubt Peterson’s immediate future as well as what will become of his titles. Khan, meantime, wrote on his Twitter page that he was seeking another opponent to fight on June 30.

“Lamont is distraught,” Barry Hunter, Peterson’s trainer, said in a telephone interview several hours after the ruling. “He’s hurt about it. We all are. Nevertheless, this isn’t something that’s going to go away, and we have to deal with it.”

Richard Schaefer, chief executive of Golden Boy Promotions, which handled publicity for the fight as well as much of Khan’s publicity, said in a telephone interview on Wednesday afternoon before the decision became official that he would not rule out legal action if the fight were abandoned, calling the actions of Peterson and his team “irresponsible.”

Peterson’s team acknowledged he had tested positive in March for synthetic testosterone — the first failed drug test of his career — and attorney Jeff Fried consulted with pathologists and medical specialists to confirm the origin of the result in an effort to absolve the unified champion of impropriety.

Paperwork submitted by Fried to the Nevada Athletic Commission included a supporting letter from John A. Thompson, a Las Vegas physician who treated Peterson for a “critically low level of free testosterone.” Peterson visited Thompson in November 2011 after complaining of fatigue and lack of concentration, which Thompson’s letter indicated are symptoms consistent with testosterone deficiency.

According to Thompson’s letter and those from other medical professionals who examined Peterson, he has hypogonadism, a condition requiring therapeutic testosterone, which unlike synthetic testosterone is not designed to enhance athletic performance. Thompson said in his letter that he administered 800 milligrams of “bioidentical testosterone derived from soy” in pellet form to Peterson, neither the type nor the amount of testosterone sufficient to produce significant athletic improvement.

“The pellets do no enhance athletic performance,” Thompson said in a telephone interview. “They couldn’t enhance athletic performance because they release so slow.”

Because bioidentical testosterone does not fall under the World Anti-Doping Agency’s prohibited list, Peterson’s team did not request an exemption that would allow an athlete to take a banned substance if it is required to treat an illness or condition.

It was unclear why Peterson tested positive for synthetic testosterone despite statements from his camp that he has taken only soy-based testosterone.

“I know it’s unfair,” Hunter said. “It’s been unfair when it comes to Lamont. Ever since Lamont won the title he’s never been treated fair.”

Peterson had requested Olympic-style drug testing be in place leading up to the rematch, and his team contracted the Las Vegas-based Voluntary Anti-Doping Association to oversee such procedures. The Nevada Athletic Commission issues only urine testing, but Olympic-style testing includes blood samples.

Testing for synthetic testosterone, though, is conducted via only urine, according to renowned internist Gary Wadler, chairman of WADA’s prohibited list and methods subcommittee.

The positive test came approximately four months after Peterson beat Khan in a 12-round split decision at the District’s Walter E. Washington Convention Center on Dec. 10. Khan and his team vehemently disputed the outcome, which included Khan having two points deducted for pushing, and petitioned both sanctioning bodies to have the result overturned or order an immediate rematch.

The WBA mandated a rematch, but shortly before the IBF was to rule, Golden Boy withdrew its grievance. The sides officially announced the rematch on Feb. 9.

Following a March 19 news conference in Los Angeles, collections officers transported random urine samples from both fighters to a WADA-accredited Olympic laboratory on the campus of UCLA. Specimens were split into an A and B sample, with UCLA reporting Peterson’s positive A sample to VADA on April 12.

VADA informed Peterson of those findings the following day and advised him of his right to have the B sample analyzed. Peterson’s team pursued that course, and that round of testing began on April 30. The results of the B sample substantiated the results of the A sample.

Peterson later submitted a random sample on April 13 that was found to be negative on May 2.