Docetaxel, ifosfamide and cisplatin in solid tumour treatment: a phase I study

Docetaxel, ifosfamide and cisplatin have proven activity in a broad range of solid tumours and interfere with different phases of the cell cycle. We performed a phase I study with the aim to determine the maximum tolerated dose (MTD) of docetaxel, ifosfamide and cisplatin in patients with solid tumours and to define the safety, dose-limiting toxicity (DLT) and the recommended dose and administration schedule of docetaxel, ifosfamide and cisplatin for further phase II testing. Docetaxel was given by 1-h infusion on day 1, followed by ifosfamide 1000 mg/m(2)/day as a continuous infusion for 5 days. Mesna was added at the same doses to the same infusion bag and was continued for 12 h after the end of ifosfamide. Cisplatin was administered as a 24-h infusion concomitantly with ifosfamide, but in separate infusion bags, either on day 5 (schedule A) or on day 1 (schedule B). Escalation steps were planned only for docetaxel (60, 75, 85 mg/m(2)) and cisplatin (50, 75, 100 mg/m(2)). No intrapatient dose escalation was permitted. Prophylactic ciprofloxacin was used after a protocol amendment was implemented. No prophylactic haematopoietic growth factors were used. Cycles of docetaxel, ifosfamide and cisplatin were given at 3-week intervals. Toxicity was scored according to National Cancer Institute Canada-Common Toxicity Criteria 2. The MTD was defined as the dose at which a DLT was observed in fewer than two of six patients during the first treatment cycle. In total, 85 patients received 309 cycles. Only three escalation steps could be explored and DLTs were observed at each dose level. In total, 32 patients and 49 cycles showed DLTs. Febrile neutropenia occurred in 20 patients (24%). Only two DLTs were nonhaematological (one cerebral infarction and one encephalopathy grade 4). Neutropenia grade 4 lasted for greater than 7 days and/or thrombocytopenia grade 4 was dose limiting in 10 patients. Febrile neutropenia occurred in five of 41 patients (12%) who received prophylactic ciprofloxacin and in 15 of 44 patients (34%) who did not. MTD was reached at level 3 (docetaxel, 75 mg/m(2) and cisplatin, 75 mg/m(2)). With a lower dose of docetaxel (60 mg/m(2)) both schedules A and B were feasible, although, overall, schedule A seemed to be better tolerated. On the basis of this phase I study, the recommended docetaxel, ifosfamide and cisplatin regimen is docetaxel (60 mg/m(2)) on day 1, ifosfamide (1000 mg/m(2)/day) on days 1-5 and cisplatin (75 mg/m(2)) given on day 5. It is associated with substantial haematological toxicity, but this is feasible provided prophylactic antibiotics are used.