The billionaire founder of an opioid manufacturer pleaded not guilty on Thursday to four federal charges that he and his co-defendants bribed doctors to write large numbers of prescriptions for the potent medication.

Dr. John Kapoor, owner of Insys Therapeutics Inc., appeared in U.S. District Court for the District of Massachusetts in Boston, according to entry notes in the case's online docket. He is charged with Racketeer Influenced and Corrupt Organizations Act conspiracy, as well as three other felonies, including conspiracy to commit mail and wire fraud and conspiracy to violate the federal Anti-Kickback Statute. The charges are pending in federal court in Boston. Prosecutors allege that Insys manufactured, marketed and sold Subsys in interstate commerce, including in Massachusetts. Kapoor was arrested in late October in his hometown of Phoenix when more than a dozen federal agents stormed his home and arrested him at gunpoint, according to court document. Four days later, Kapoor, 74, retained high-profile Nixon Peabody partner Brian Kelly to represent him.

During Thursday's proceeding, U.S. Magistrate Judge Jennifer Boal of the District of Massachusetts heard arguments about Kelly's pending motion to modify the conditions of Kapoor's release, namely that he be forced to wear an electronic monitoring bracelet pending trial. As part of his release on a secured bond of $1 million, Kapoor may not travel without permission outside Maricopa County, Arizona.

“Dr. Kapoor is a daily jogger, and the cumbersome bracelet makes it virtually impossible for him to run,” Kelly wrote in the motion. “The government cannot carry its burden of showing that the electronic bracelet condition is necessary to reasonably assure Dr. Kapoor's appearance, and it is not fair to impose on Dr. Kapoor alone a condition that would prevent him from engaging in his preferred manner of exercise while he spends many stressful months awaiting the resolution of this case.”

The government has filed an opposition to Kapoor's motion, arguing that the weight of the evidence and the doctor's financial resources justify the electronic monitoring.

Boal took the matter under advisement and scheduled a status conference for Dec. 19.

At issue in the case is Insys drug Subsys, a fentanyl-based oral spray medication meant to treat only patients with cancer pain. In addition to the bribery allegations, the indictment alleges that Kapoor and his co-defendants—the former Insys CEO and other former executives—defrauded insurers who were reluctant to approve payment of the drug for non-cancer patients.