Phoenix-based opioid drug-maker Insys Therapeutics, Inc. agreed Friday to pay $4.45 million to resolve a lawsuit by Illinois' attorney general. Insys is accused of deceptive marketing practices to sell its opioid-based cancer pain drug.

The settlement will resolve claims that the company illegally promoted its product Subsys to doctors.

The Illinois case piggybacks a series of investigations centered on Subsys, an under-the-tongue spray intended for cancer patients that contains fentanyl, a highly addictive and regulated synthetic opioid.

Those investigations led to federal charges of six former Insys executives and managers, accused of engaging in a scheme to bribe doctors to prescribe Subsys. 

According to the U.S. Centers for Disease Control and Prevention, opioids were involved in over 33,000 deaths in 2015.

The company said earlier this month it would not admit any wrongdoing.