Insys Therapeutics founder John Kapoor resigned his seat on the pharmaceutical company's board of directors Sunday.
The resignation announcement followed Kapoor's arrest Thursday in Phoenix on federal charges alleging he participated in what the U.S. Attorney's Office in Massachusetts deemed "a nationwide conspiracy to profit by using bribes and fraud" for illegal distribution of its fentanyl spray, an addictive opioid intended for cancer patients.
That same day, President Donald Trump officially declared the opioid crisis a nationwide public health emergency.
Kapoor is accused of conspiracy, fraud, racketeering and other felonies. The billionaire posted $1 million bail in cash Sunday.
Kapoor's arrest follows other indictments against Insys executives accused of providing kickbacks to physicians for prescribing Subsys, another opioid drug.
In the latest indictment, Kapoor and other Insys employees are accused of bribing doctors to write prescriptions for the fentanyl-based pain medication indicated for late-stage, cancer patients in extreme pain, often prescribing it for non-cancer patients.
The indictment also alleges Kapoor attempted to mislead and defraud insurance providers, who were reluctant to approve payment for the drug for non-cancer patients.
Kapoor took the helm as Insys' president and CEO in November 2015 after Michael L. Babich resigned as CEO.
Babich and other former executives and managers are expected to go to trial in October 2018. The latest indictment brings new charges against Babich and others.
Federal authorities began investigating Insys as early as 2013.