The research team from The Ohio State University have devised a new dosing schedule for the drug to increase its anti-tumour activity and cure the potentially fatal disease.
The trials were conducted over 116 patients with advanced CLL, who were treated with the drug flavopiridol (alvocidib).
"Flavopiridol has bridged the way for several CLL patients to receive a curative stem cell transplant," said Dr. John Byrd, associate director of translational research and principal investigator of the phase II trial.
In the 1980s, animal tests showed flavopiridol to be a potent cancer-fighter.
But when researchers gave it to humans in repeated trials using a continuous prolonged infusion, the drug proved ineffective and was essentially forgotten.
The Ohio State researchers had later discovered that flavopiridol binds to proteins in human blood, which ties up much of the available drug and leaves less free drug in the bloodstream to kill cancer cells.
In essence, patients were not getting enough of the drug to be effective.
With the new dosing schedule, the researchers found that drug could effectively kill cancer cells.
"The new schedule increased the drug's blood level enough to kill cancer cells in humans, said Dr. Michael Grever, chairman of the department of internal medicine and co-leader of the Experimental Therapeutics program at Ohio State's Comprehensive Cancer Center.
The findings were presented at 50th Annual Meeting of the American Society of Hematology (ASH).