COMPARISON OF 5 VS 10 MU-G/KG PER DAY OF GM-CSF FOLLOWING DOSE-INTENSIFIED CHEMOTHERAPY WITH CISPLATIN, ETOPOSIDE, AND IFOSFAMIDE IN PATIENTS WITH ADVANCED TESTICULAR CANCER

Despite the increasing use of granulocyte-macrophage colony-stimulating factor (GM-CSF) for the treatment of chemotherapy-induced neutropenia, few studies have focused on the activity and toxicity of the different clinically used dosages of GM-CSF. Forty-four patients with ''poor-risk'' (advanced disease, according to the Indiana University classification) testicular cancer were treated with a dose-intensified chemotherapy regimen of cisplatin (30 mg/m2), etoposide (200 mg/m2), and ifosfamide (1.6 g/m2), given on days 1-5 for a total of four cycles at planned intervals of 21 days. Patients (pts) received GM-CSF, either 10 (22 pts; 70 cycles evaluable) or 5 mug/kg body wt. daily s.c. (22 pts; 72 cycles evaluable), starting the first day after chemotherapy for 10 consecutive days. Overall, 34 patients (78%) achieved a favorable response (CR or PR with negative tumor markers), six patients (14%) failed this chemotherapy regimen, and four patients (9%) died of therapy-related complications. The durations of both neutropenia and thrombocytopenia increased with the number of treatment cycles given. The duration of granulocytopenia after the fourth PEI cycle was significantly shorter for patients receiving 10 mug/kg than for those with 5 mug/kg per day of GM-CSF (9 vs 13 days; p < 0.05). The median duration of thrombocytopenia <20000/mul after the fourth cycle of PEI was also significantly reduced in favor of patients receiving 10 mug/kg of GM-CSF (4 vs 9 days; p < 0.02). However, there were no differences in the frequency of severe infections or in the achieved dose intensity. Five patients (11%) discontinued GM-CSF due to side effects (three anaphylactoid-type reactions, one myalgia and fever, one cutaneous toxicity). No difference in the frequency of side effects was seen between patients receiving 5 and those receiving 10 mug/kg per day of GM-CSF. The dose of 5 mug/kg per day of GM-CSF may be sufficient to ameliorate neutropenia following standard-dose chemotherapy, while higher dosages of GM-CSF may be advantageous in patients receiving repetitive cycles of dose-intensified chemotherapy.