GM-CSF, CARBOPLATIN, DOXORUBICIN - A PHASE-I STUDY

Dose intensification has the potential to increase the response freque ncy of chemosensitive tumors to chemotherapy. G-CSF and GM-CSF offer t he possibility of dose-intensifying chemotherapy without prohibitive m yelosuppression. A phase I study was undertaken to identify the maximu m tolerated dose (MTD) of carboplatin that could be administered with a fixed dose of doxorubicin, 60 mg/m2, administered every 28 days. Fur ther escalation of the carboplatin dose was then attempted, with the c oncomitant addition of GM-CSF 10 mg/kg per day on days 1-21. We had 21 patients, 13 with prior therapy, who were eligible. In all, 60 course s of therapy were delivered, all with doxorubicin and with carboplatin doses of 250 mg/M2, 325 Mg/M2 and 400 Mg/M2. At carboplatin 400 Mg/M2 and doxorubicin 60 Mg/M2, thrombocytopenia was dose limiting. The add ition of GM-CSF did not allow further escalation. Of the 6 patients tr eated with carboplatin 400 Mg/M2, doxorubicin 60 Mg/M2, and GM-CSF, gr ade 4 granulocytopenia and thrombocytopenia were seen in 4 and 5 patie nts, respectively. The severity of thrombocytopenia was related to the calculated carboplatin AUC and also to baseline platelet count and pr ior therapy. In addition, the interaction of GM-CSF and chemotherapy, especially carboplatin-based, may be more complex than originally anti cipated.