Updated at 5:45 p.m. ET: Lance Armstrong lost three major sponsorship contracts Wednesday and stepped down as the chairman of the Livestrong charity he founded as the fallout from doping allegations continued to plague the former champion cyclist.
Armstrong announced Wendesday he is stepping down as chairman of Livestrong so that the cancer-fighting charity can focus on its mission instead of the doping accusations.
"To spare the foundation any negative effects as a result of controversy surrounding my cycling career, I will conclude my chairmanship," Armstrong said in a statement.
The resignation came amid a cascade of bad news for the cyclist who was once among the highest-paid endorsers in the sports world. Nike, Anheuser-Busch and Trek bicycles all said they would no longer use Armstrong as a spokesman for their products.
Jeff Garvey, an Austin, Texas-based venture capitalist and vice chairman of Livestrong, will take over as chairman. Armstrong will remain on the board, a foundation official said.
Nike, the world's largest sports shoe and apparel company, severed its ties with Armstrong, but said it would continue to support Livestrong.
"Due to the seemingly insurmountable evidence that Lance Armstrong participated in doping and misled Nike for more than a decade, it is with great sadness that we have terminated our contract with him," Nike said in a statement.
Anheuser-Busch, the giant beermaker, took a similar tack, saying in a statement that it decided not to renew its relationship with Armstrong, which expires at the end of of this year, although it will continue to back Livestrong. Armstrong had previously appeared in ads for Michelob Ultra.
Late in teh day Trek Bicycle of Waterloo, Wis., said it was also terminating its relationship with Armstrong, citing the voluminous evidence against him published last week by the U.S. Anti-Doping Agency.
Armstrong is set to lose his record seven Tour de France titles after the USADA's 1,000-page report cooncluded the now-retired American took part in and organized an elaborate and sophisticated doping scheme on his way to his unrivaled success on the Tour.
Slideshow: Life of Lance Armstrong
Armstrong has always denied he took banned substances during his glittering career but refused to challenge the USADA charges against him.
Armstrong founded the Lance Armstrong Foundation in 1997 after being diagnosed with testicular cancer in late 1996. The foundation launched Livestrong in 2003 to provide support services to cancer patients.
His departure as chairman comes just two days before the foundation's fund-raising gala in Austin, Texas, where Armstrong lives. Celebrities such as Sean Penn and Ben Stiller are expected to attend, with comedian Robin Williams and singer Norah Jones to provide entertainment.
"It is his effort to inoculate the foundation against any risk or damage associated with current controversy in the cycling world," Livestrong spokeswoman Katherine McLane told Reuters in an interview.
So far, the foundation's financial health appears not to have suffered from Armstrong's cycling scandal.
Contributions have actually risen this year as the USADA probe gathered momentum. For the year 2012 to date, the foundation has reported revenue of $33.8 million, up 2.1 percent from this point a year ago, according to documents provided to Reuters.
Since late August, when Armstrong said he would not contest the USADA findings and the agency said it planned to strip him of his titles, Livestrong has received more than 16,000 contributions, averaging about $97 each. "This is almost twice normal levels," said Rae Bazzarre, another Livestrong spokeswoman.
Cycling's world governing body, the International Cycling Union, has yet to rule on the USADA report. They can either confirm Armstrong's life ban and strip him of his seven Tour titles or take the matter to the Court of Arbitration for Sport.
The USADA report accused Armstrong, as head of the US Postal Service Pro Cycling Team, of running "the most sophisticated, professionalized and successful doping program that sport has ever seen." The report included sworn testimony of 26 people, including 15 riders, who described years of performance-enhancing drug use.
The Associated Press and Reuters contributed to this report.