Intake of grapefruit juice could increase the effectiveness of cancer drug and it lets cancer patients to receive the similar benefits from low dose of an-anti cancer drug called Sirolimus, found a new clinical study. Sirolimus was the first of a series of drugs, known as mTOR inhibitors, used by transplant patients to prevent rejection that also have anti-cancer properties.
Researchers from the University of Chicago Medicine revealed that cancer patients taking sirolimus may get more of its anti-cancer benefits if they drink eight ounces of glass of grapefruit juice every day along with the drug. The drug-juice combination was so effective that patients who drank grapefruit juice gained three benefits by three times compared to those who took the drug alone.
The drug-juice combination could help cancer patients avoid side effects associated with high doses of the drug and cut the cost of the medication. A team led by Dr Ezra Cohen, a cancer specialist at the University of Chicago Medicine, arranged three concurrent phase-1 trials of sirolimus. They registered one-hundred-forty patients with incurable cancer and no known effective therapy.
Patients were divided into three groups, first group received only sirolimus, second group received sirolimus and ketoconazole, and third group received sirolimus and grapefruit juice. The team hoped these different combinations would improve absorptive power of the drugs. At first, patients were given very low doses of sirolimus.
Then, the amount of dose was slowly increased as time went on so as to determine how much of the drug was required in each setting to reach targeted levels, so that patients got the utmost anti-cancer effect with the least side effects. Eventually, the study findings showed that drinking eight ounces of grapefruit juice per day helped increase sirolimus levels by three-hundred-and-fifty percent.
The effect was even higher for those who took ketoconazole, with sirolimus levels increasing by five-hundred percent. On the whole, the optimal dose for those taking sirolimus on its own was ninety mg, while those drinking grapefruit juice only needed thirty-five mg of sirolimus, and those on the ketoconazole combination needed only sixteen mg.
Lead author Dr Cohen stated grapefruit juice, and drugs with a similar mechanism, can significantly increase blood levels of many drugs. But this has long been considered an overdose hazard. Instead, they wanted to see if grapefruit juice could be used in a controlled fashion to increase the availability and efficacy of sirolimus.
Grapefruit juice’s pharmaceutical prowess stems from its ability to inhibit enzymes in the intestine that break down sirolimus and several other drugs. The effect begins within a few hours of grapefruit juice administration. It wears off gradually over a few days, added Dr Cohen. The findings were published in Clinical Cancer Research.