The American lost his seven Tour de France titles last year and in January admitted to years of performance-enhancing substance use in the most spectacular drugs case in recent years. (Agencies)
Following his public confession, the IOC ordered the return of the bronze medal he won in the time-trial at the Sydney 2000 Games and declared the race results void.
IOC Vice President Thomas Bach, who also heads the IOC's juridical commission, said the former rider had not challenged the decision to strip him of his medal.
"We still do not have the medal back. We will continue to work with the United States Olympic Committee to get this medal back as requested in our decision," Bach told an IOC session in the Argentine capital.
"This (the IOC's January) decision has been communicated to Mr Armstrong and the USOC. This decision has not been appealed neither by Mr Armstrong, nor by the USOC and what we are lacking, sadly, is getting back the medal. Legally the case for the IOC is closed," he said.
The once-revered athlete is battling to hang on to what remains of his reputation and his earnings and is fighting several lawsuits, including one from the U.S. Justice Department.
In February, the Justice Department said it was joining a fraud suit filed in 2010 by Floyd Landis, a former Armstrong team mate. Landis filed the suit under a federal law that allows whistle-blowers to report fraud in exchange for a reward.
The US Postal Service paid USD 40 million from 1998 to 2004 to have Armstrong and his team mates from Tailwind Sportswear its logo during record-breaking wins. At least USD 17.9 million of these fees went to Armstrong, according to the government.
The American lost his seven Tour de France titles last year and in January admitted to years of performance-enhancing substance use in the most spectacular drugs case in recent years.