Cohen and his team studied 138 patients with cancer who had no conventional treatment options in their study. For this so-called Phase I study, which tests the efficacy and tolerability of therapy in a few subjects, they divided the participants into three groups: one received only sirolimus, a second sirolimus and grapefruit juice, and the last sirolimus and ketoconazole. Ketoconazole is an active ingredient used against fungal infections, especially in people with immunodeficiencies or autoimmune diseases. He was used in the study because he also inhibits the intestinal enzymes that degrade the sirolimus.
First, the ideal dose was determined for each patient, that is, the amount at which the greatest effect with the fewest side effects occurred. Then the different groups were compared. Result: Subjects who consumed eight ounces of grapefruit juice a day - just over 0.2 liters - but took only about one-third of the optimal dose of sirolimus had 350 percent more of the drug in their blood than if they were the normal amount took the drug and drank no juice. The effect was the same. Those patients who ingested additional ketoconazole even had 500 percent more sirolimus in their blood, even if they were only about one-seventh of the optimal dose? however, there were many side effects in these subjects.
While there was no ultimate cure for any of the cancer patients, there was no worsening of disease in 30 percent of patients during the study period, so no further tumor growth. One of the patients was particularly prominent in the study: in his case, the tumors shrank significantly and did not continue to grow for more than three years. According to the researchers, the effect of grapefruit varies from person to person, since different amounts of sirolimus are also broken down in the patients, depending on the intestinal flora. However, before one can give general recommendations on the consumption of grapefruit juice, it would be necessary to investigate even more intensively what the effects of the interaction between the juice and the active substance really are, according to the researchers. displayEzra Cohen et al .: Clinical Cancer Research doi: 10.1158 / 1078-0432.CCR-12-0110 © science.de - Gesa Seidel