Greek sprinters Kostas Kenteris and Katerina Thanou have lost their bid to return to action.
The sprinters were provisionally suspended in April 2005
They have been suspended since December 2004 after allegedly missing three drugs tests before the 2004 Olympics.
The Court of Arbitration for Sport is due to decide whether the duo should be banned at a hearing starting in Lausanne on 26 June.
But CAS has ruled that the sprinters cannot return to action before that verdict has been reached.
Kenteris and Thanou appeared before CAS in October, but there was not sufficient time for all witnesses to testify.
Kenteris and Thanou were provisionally suspended by athletics' governing body, the IAAF, last year.
The decision was subsequently overturned by an independent Greek tribunal.
The IAAF then appealed to CAS, which will have the final say on the matter.
Kenteris was the 200m champion at the 2000 Olympics and Thanou was the women's 100m silver medallist at the same Games.
The IAAF allege that the athletes failed to appear to give samples in Chicago and Tel Aviv shortly before the 2004 Games and again in Athens on 12 August.
However, the duo argue they were not sought by the testers in Athens, and this was accepted by both the independent Greek tribunal and CAS.