Intermittent, repetitive administrations of irinotecan (CPT-11) reduces its side-effects

To reduce the side-effects of irinotecan (CPT-11) while maintaining its anti-cancer effects against recurrent ovarian carcinomas, we devised a novel administration schedule for CPT-11 single chemotherapy. It consisted of an initial dose of 70 mg/m2, followed by increasing the dose to 100 mg/m2 every 10 days (three times per month) for 9 cycles. Nineteen patients with refractory or recurrent ovarian carcinomas were treated. In comparison with a late phase II study of single CPT-11 chemotherapy in Japan (100 mg/m2 every 7 days; four times per month), the number of patients who suffered from leukocytopenia and diarrhea higher than grade 3 was significantly lower with our new method (36.8 versus 57.1%; P<0.01 and 0 versus 19.2%; P<0.001, respectively). The total response rate was 26% (5/19). This rate was almost equal to a late phase II study. We suggest that our new protocol of single CPT-11 administration should be available clinically to all patients for reducing the side-effects while maintaining its anti-cancer effects. CPT-11 is useful in patients with refractory ovarian carcinomas as a second- or third-line chemotherapy.