|Mayweather had demanded Olympic-style drug testing before the fight [AFP]
Talks over the hotly anticipated welterweight bout between Filipino Manny Pacquiao and American Floyd Mayweather Jr. have failed, leaving the prospective bout all but over in what would have been the richest fight in boxing history.
The fight was slated for March 13 at the MGM Grand Garden in Las Vegas.
Although neither side was allowed to publicly discuss the specifics of their dispute, Mayweather apparently balked at a compromise over the stringent drug-testing requirements his camp insisted upon.
"No deal was reached and Manny is moving on," communications expert Fred Sternburg told news agency Reuters on behalf of Pacquiao's promoter Bob Arum.
Sternburg said the respective parties could not settle their differences after nine hours of mediation on Tuesday followed by further discussions on Wednesday.
"I knew this was going to happen,'' said a weary Bob Arum, Pacquiao's promoter.
"You had to play it out.''
The World Boxing Organisation welterweight title bout was thrown into doubt last month when Mayweather demanded Olympic-style dope testing, a request rejected by Pacquiao.
Mayweather's camp had called for random blood and urine sampling prior to and after the proposed March 13 fight as mandated by the US Anti Doping Agency.
Pacquiao agreed to have blood taken for testing before the initial media conference and immediately after the fight but would not agree to have blood drawn within 30 days of the bout.
On December 28, Arum said he would announce a new opponent for the Filipino southpaw but just hours later he backtracked, saying he would ask the boxer to reconsider his objection to blood testing.
Arum was left fuming by Mayweather, who fought under Top Rank promotion
for several years.
"I've been saying this for years: He's a psychological coward who doesn't want to fight anybody who has a chance of beating him"
"I've been saying this for years: He's a psychological coward who doesn't want to fight anybody who has a chance of beating him,'' Arum said.
"He walked away from a rematch with Oscar (De La Hoya) that would have paid him a fortune because De La Hoya held him close in the first fight (in May 2007).''
Pacquiao (50-3-2) had been scheduled to defend the WBO title he won in November by stopping holder Miguel Cotto in the 12th round in Las Vegas.
Pacquiao won an unprecedented seventh title in seven weight classes to set up the best pound-for-pound showdown against unbeaten Mayweather (40-0) in what was widely expected to be boxing's biggest revenue-producing fight
After stellar pay-per-view numbers from their previous fights, both Pacquiao and Mayweather likely stood to make more than $25 million from the welterweight bout.
After Mayweather went public with his requests for drug testing that went beyond the standards of the Nevada Athletic Commission, Pacquiao filed a lawsuit last week alleging Mayweather and his camp defamed him by accusing him of using performance-enhancing drugs.
That led to mediation, which apparently produced a solution acceptable to everybody except Mayweather, according to Arum.
Arum said there's "no chance ever of salvaging it for March, no chance for it ever to happen.''
He plans to propose a mid-March bout with WBA super welterweight champion Yuri Foreman to Pacquiao, who could become a champion in his eighth weight class.