NEW YORK — Lance Armstrong has stepped down as chairman of the cancer charity he founded, Livestrong, after US anti-doping officials issued a scathing report detailing his use of performance-enhancing drugs for years as one of the world's premier cyclists, the foundation said Wednesday. Separately, one of his main corporate sponsors, Nike Inc., said it was ending its sponsorship of Armstrong. “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. Armstrong is set to lose his record seven Tour de France titles after the US Anti-Doping Agency published a 1,000-page report last week that said the now-retired American took part in and organized an elaborate and sophisticated doping scheme on his way to his unrivalled success on the Tour. Armstrong has always denied he took banned substances during his glittering career but refused to challenge the US Anti-Doping Agency (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. Armstrong, who was not paid a salary as chairman of the foundation, will remain on its 15-member board. His duties leading the board will be turned over to vice chairman Jeff Garvey, who was founding chairman in 1997. Doctor denies accusations Italian doctor Michele Ferrari denied Tuesday accusations from the USADA that he masterminded a doping program for American cyclist Lance Armstrong. “This collaboration consisted exclusively of advice on training, saddle height adjustments, aerodynamic positioning, locations for training programs and competitions: NOTHING to do with doping,” Italian Ferrari wrote on his website. UCI under pressure The International Cycling Union (UCI) is under pressure to reveal how Armstrong was able to escape detection for doping for so long. According to a number of his former teammates, the seven-time Tour de France winner bragged about having managed to suppress a positive test for the blood booster erythropotein (EPO) on the 2001 Tour of Switzerland. The head of the Lausanne laboratory involved confirmed to US investigators that the sample in question was disputed, although given the science at the time, it was not considered strong enough evidence to put before a court. Simply put, the “positive” test was an assumption. Tests for EPO had only been approved two months earlier. “It wasn't possible for my predecessor (Hein Verbruggen) to hide the result,” the current president of the UCI, Pat McQuaid, said in 2010, later saying: “There was no positive test.” But the formal position of the UCI and its refusal to allow the US Anti-Doping Agency (USADA) to re-examine the test without Armstrong's consent has prompted opponents to claim it is compromised. More troubling still for the UCI is that it accepted two donations from Armstrong between 2002 and 2005 for a total of $125,000, which were used to buy anti-doping technology, including a blood analysis machine. “You have to consider the context at the time. In 2002, there were no claims of doping against Armstrong,” McQuaid said in 2010, although he acknowledged that the organization would be careful in future about any similar donations in future. Others, such as the wife of cyclist Greg LeMond, go further by raising the possibility of corruption, claiming that sportswear manufacturer Nike donated $500,000 to suppress a positive test on the 1999 Tour. — Agencies