Privitera crashed during a descent, losing his helmet and colliding with a gate, Italian media reported. He was transported to the hospital but succumbed to his injuries.
Authorities are investigating the circumstances surrounding the crash.
"Samuele was and always will be the life and personality of this team. This team has always been a small family, and moments like this are unimaginable," Axel Merckx, owner of Hagens Berman Jayco, said in a statement.
The second stage of the race, which takes place in northern Italy's Aosta Valley near the French border, has been cancelled.