Italian Damiano Cunego retained the race leader's yellow jersey after his rivals failed to put him to the sword in the 222.8 km ride from Vaduz in Liechtenstein to here, the final climbing stage of the race.
Leopard rider Schleck, a two-time runner-up in the Tour de France, finished 35secs adrift of Vacansoleil rider De Gendt with Cunego leading home a small group containing all his rivals 4:37 later.
In Paris, the International Cycling Union (UCI) is to stop riders who have been found guilty of doping to join a team staff in its latest drive to eradicate drugs from its sport.
"The UCI Management Committee approved the introduction of a new article in the regulations aiming to prevent anyone found guilty of infringing the Anti-Doping Regulation during his cycling career from obtaining a license authorizing him to take on a role in cycling as a member of a team's staff," the UCI said in a statement on Friday.
However, a rider found guilty of doping may enter a team staff if he committed only one doping offense that was not sanctioned by a two or more year ban and five years after five years have elapsed between the moment of the violation and the first day of the year for which the license is granted.
All three conditions must be fulfilled for a rider to be part of a team as "a general manager, team manager, coach, doctor, paramedical assistant, mechanic, driver or other function as specified on the license," the regulations said.
The rule will apply on any doping offense committed as of July 1 this year.
Several former riders with a doping past currently have a managerial role in professional cycling teams.
Kim Andersen, who tested positive three times, is a sports director at Andy Schleck's Leopard-Trek team, while fellow Dane Bjarne Riis, the Saxo Bank-SunGard team manager, admitted to doping when he won the Tour de France in 1996.
The UCI implemented the biological passport in 2008 to track any blood changes in riders against an original profile. Several riders have subsequently been banned on the basis of the passport.
1. Thomas De Gendt (Belgium / Vacansoleil) 5hrs 38mins 42secs" 2. Andy Schleck (Luxembourg / Leopard) +35" 3. Jose Joaquin Rojas (Spain / Movistar) +48" 4. Christian Vande Velde (US / Garmin) +51" 5. Alberto Losada (Spain / Katusha) +54" 6. Sergey Lagutin (Uzbekistan / Vacansoleil) +1:33" 7. Jan Bakelants (Belgium / Omega Pharma - Lotto) +1:34" 8. Marco Marcato (Italy / Vacansoleil) +2:30" 9. George Hincapie (US / BMC Racing) 10. Manuele Boaro (Italy / Saxo Bank)
1. Damiano Cunego (Italy / Lampre) 27hrs 09mins 49secs 2. Bauke Mollema (Netherlands / Rabobank) +1:23" 3. Steven Kruijswijk (Netherlands / Rabobank) +1:36" 4. Frank Schleck (Luxembourg / Leopard) +1:41" 5. Levi Leipheimer (US / RadioShack) +1:59" 6. Jakob Fuglsang (Denmark / Leopard) +2:38" 7. Mathias Frank (Switzerland / BMC Racing) +3:10" 8. Laurens ten Dam (Netherlands / Rabobank) 9. Giampaolo Caruso (Italy / Katusha) +3:11" 10. Tejay Van Garderen (US / HTC - Highroad) +3:22"
