Phase I evaluation of the effects of ketoconazole and rifampicin on cediranib pharmacokinetics in patients with solid tumours

To investigate any effect of a CYP3A4 inhibitor (ketoconazole) or inducer (rifampicin) on cediranib steady-state pharmacokinetics in patients with advanced solid tumours. In two Phase I, open-label trials, patients received once-daily oral doses of cediranib alone [20 mg (ketoconazole study); 45 mg (rifampicin study)] for 7 days followed by cediranib at the same dose with ketoconazole 400 mg/day for 3 days or once-daily rifampicin 600 mg/day for 7 days, respectively. Patients then continued to receive once-daily cediranib. In the ketoconazole study, 46 patients were dosed; 38 were evaluable for C ss,max, 36 for AUCss. gMean AUCss and C ss,max for cediranib 20 mg increased by 21 % (94 % CI 9–35 %) and 26 % (94 % CI 10–43 %), respectively, in the presence of ketoconazole. In the rifampicin study, 64 patients were dosed; 44 were evaluable for C ss,max and 41 for AUCss. gMean AUCss and C ss,max for cediranib 45 mg decreased by 39 % (90 % CI 34–43 %) and 23 % (90 % CI 16–30 %), respectively, in the presence of rifampicin. gMean ratios for AUCss and C ss,max were >1 for ketoconazole and