[Phase I clinical study of combined cisplatin and carboplatin therapy in lung cancer]

A phase I clinical study (a dose escalation test) of combined cisplatin (CDDP) + carboplatin (CBDCA) therapy was carried out in patients with primary or secondary lung cancer (PS 0-2) who had given prior informed consent to the study. The dose level of CDDP was set at 80 mg/m2, while five dose levels (200, 250, 300, 350, 400 mg/m2) of CBDCA were used. Three patients were allocated to each CBDCA dose group. Blood samples were taken immediately before and 0.5, 1, 2, 4, 6 and 24 hours after injection, and were examined for total Pt and free Pt level. The maximum tolerated dose (MTD) was CDDP 80 mg/m2 + CBDCA 400 mg/m2. Thrombocytopenia and leukopenia served as dose limiting factors (DLF). Total Pt and free Pt levels in blood after this combined therapy were higher than those after treatment with CDDP alone. The results from this study suggest that CDDP 80 mg/m2 + CBDCA 350 mg/m2 would be a suitable dose for phase II study of this combined chemotherapy. A multi-center pilot study based on these findings is now under way.