BEIJING—China set new price restrictions for some cancer and blood-related drugs, as the country's leaders attempt to overhaul the health-care system and reduce costs.

Retail-price cuts averaging 17% will take effect Oct. 8 for 95 oncology, immune-system and blood-related drugs and 200 formulations, the National Development and Reform Commission, China's main economic planning agency, said on its website Tuesday.

The...