A pharmaceutical company founder accused of leading a conspiracy to bribe doctors to prescribe a powerful opioid pain medication will fight the charges against him and believes he will be vindicated, his attorney said Thursday.

John Kapoor, of Insys Therapeutics Inc., pleaded not guilty in Boston's federal courthouse, and his lawyer urged the judge to allow him to remove an electronic monitoring bracelet while he awaits trial. Attorney Brian Kelly said Kapoor isn't a flight risk and wants to clear his name in court.

"He's not going to desert the USA because of this case," Kelly told the judge. "He doesn't believe it's a strong case. He wants to fight this case."

The case centers on a highly addictive fentanyl spray that's made by Insys Therapeutics, a specialty pharmaceutical company whose corporate offices are in Chandler, Arizona.

Kapoor, 74, and other Insys executives and managers are charged with offering kickbacks to doctors to write large numbers of prescriptions for the potent opioid that's meant for cancer patients called Subsys. Former CEO Michael L. Babich and others are set to go to trial next year and have pleaded not guilty.

The charges against Kapoor of racketeering conspiracy, mail fraud conspiracy and wire fraud conspiracy each carry a sentence of up to 20 years in prison upon conviction. Conspiracy to violate the anti-kickback laws calls for up to five years in prison.

Kapoor, who appeared in court on Thursday in a suit and tie, has been free on $1 million bail since he was arrested by a dozen armed agents in his home state of Arizona last month, according to his attorney. He emigrated from India decades ago, is now a U.S. citizen and handed over his passport to authorities after his arrest.

Assistant U.S. Attorney Nathaniel Yeager said prosecutors fear he will flee the country, adding that they believe he has access to at least $2 billion.

The judge didn't immediately issue a ruling Thursday on whether to remove Kapoor's GPS monitoring requirement.