In order to develop a more dose-intensive induction regimen for the treatment of far-advanced testicular tumours, the German Cooperative Group for Testicular Tumours started a dose-escalation trial of cisplatin, etoposide and ifosfamide. At the first dose level 18 patients with advanced testicular cancer (Indiana University classification) received cisplatin 25 mg/m2, etoposide 120-150 mg/m2 and ifosfamide 1.2 g/m2 for 5 days every 3 weeks. Of these, 13 patients (72%) became tumour-free, 2 achieved a stable, marker-negative partial remission, 2 had progressive disease and 1 patient died of Clostridium sepsis. The main toxicity was myelosuppression with a white blood cell nadir of 900/microliters and a thrombocyte nadir of 47,000/microliters. Granulocytopenic fever occurred in 43% of all cycles. At the second dose level 15 patients received cisplatin 30 mg/m2, etoposide 150 mg/m2 and ifosfamide 1.6 g/m2 five times every 3 weeks together with s.c. recombinant granulocyte/macrophage-colony-stimulating factor (GM-CSF) 10 micrograms/kg on days 6-15. Acute toxicity was severe with a white blood cell nadir of 300/microliters and thrombocyte nadir of 11,000/microliters. The duration of the thrombocytopenia increased with cycle number; 63% of all cycles were associated with granulocytopenic fever and in 83% platelet transfusions were required. One patient died from acute renal failure and Aspergillus sepsis; 3 patients experienced adverse reactions to GM-CSF, requiring omission of this drugs in 2; 33% had grade 3 or 4 mucositis. At this dose level 8 patients (53%) became tumour-free, 4 patients (26%) had marker normalization with irresectable residual disease and 2 patients were treatment failures. Though acute toxicity was severe at this dose level, there was no unexpected or unmanageable organ toxicity and thus patients are now entered at dose level 3, which consists of cisplatin 30 mg/m2, etoposide 200 mg/m2 and ifosfamide 1.6 g/m2 for 5 days and GM-CSF 10 micrograms kg-1 day-1 on days 6-15 s.c.