According to the court’s public relations, the rulings for Dr. Hamid Qareh Hasanlou, Hossein Mohammadi and Reza Arya were cancelled due to faulty investigations.
Theirs were part of 16 cases being reviewed by the Supreme Court. The three were given capital punishment in connection with the incident.
The verdicts for two other people sentenced to death over the incident were confirmed by the supreme court.
The others face long-term jail sentences, including three who are under 18 years old.
Iran has been the scene of unrest and deadly riots since the death of a 22-year-old girl in police custody in mid-September.
Hundreds of people including security forces have been killed during the period.