Robert R. Courtney, 49, apologized to the victims of the scheme and changed his plea to avoid a federal court trial that had been scheduled to begin March 11. He faced a maximum sentence of 196 years in prison if convicted.
The plea agreement calls for Courtney to be sentenced to 17-1/2 to 30 years, requires him to tell investigators everything and calls for restitution. He and his pharmacies were fined $15 million. U.S. District Judge Ortrie Smith ordered a pre-sentence investigation.
Courtney, the son of a retired Assemblies of God minister, admitted misbranding, adulterating and mislabeling the chemotherapy drugs Gemzar, Taxol, Paraplatin and Platinol. He admitted in court he was guilty of reckless endangerment, a statement that sparked tears among victims' families, and said he had no "rational explanation" for his actions.
More than $8 million of Courtney's assets were frozen by the government when he was charged and stripped of his pharmacy licenses, forcing him to sell the two drugstores he owned in Kansas City and Merriam, Kan.
Courtney also faces more than 200 fraud and wrongful death lawsuits filed by cancer patients and their survivors. His attorney, Jean Paul Bradshaw, said Courtney plans to resolve those as well.
"Today, Robert Ray Courtney finally admitted under oath what some of us have known since last August," U.S. Attorney Todd Graves said. "He robbed others of their hopes for better health and longer lives. Our work will continue beyond today to determine the full scope of his deeds."
If investigators determine Courtney is not fully truthful, more charges could be filed.
Under the plea agreement, Courtney admitted that on 20 occasions he tampered with intravenous drug mixtures that did not contain the amounts of the prescription chemotherapy drugs Taxol and Gemzar ordered by treating physicians.
Taxol is used to treat ovarian, breast and lung cancer, and Gemzar is used to treat pancreatic cancer and certain lung cancers.
Courtney also admitted to investigators he tampered with the prescriptions for 34 patients on 158 separate occasions.
Courtney allegedly told investigators he diluted Paraplatin and Platinol on an unspecified number of occasions, conspired to traffic in stolen drugs, including Taxol and Gemzar, and filed false Medicare claims.
Court documents indicated Paraplatin and Platinol taken from Courtney's Research Medical Tower Pharmacy were diluted to between 13 percent and 53 percent of their prescribed strengths.
A syringe of Procrit obtained from Courtney's pharmacy by the Kansas City Internal Medicine Group and given to investigators shortly after his arrest in August contained only 15 percent of the prescribed dosage.
Courtney said he began diluting medication to pay more than $600,000 in taxes and a $330,000 pledge to his church.
The scheme came to light after a sales representative from Eli Lilly Co. noticed Research Medical Tower Pharmacy had ordered much less Gemzar than the billings to doctors indicated.
Courtney was among the first pharmacists to premix chemotherapy drugs for doctors because nurses were afraid to handle the cell-killing chemicals. The premixed dosages were delivered directly to doctors' offices.
Notable deaths of 2014 [PHOTOS]