Mitoxantrone, etoposide, and cytarabine plus cyclosporine for patients with relapsed or refractory acute myeloid leukemia - An Eastern Cooperative Oncology Group Pilot Study

BACKGROUND. One potential mechanism of drug resistance to chemotherapy is t he overexpression of multidrug resistance (MDR) genes coding for P-glycopro tein (P-gp), which leads to reduced intracellular retention of chemotherapy . This study tested the efficacy and toxicity of mitoxantrone, etoposide, a nd intermediate dose cytarabine (MEC) with cyclosporine (CSP) as an MDR mod ulator in patients with recurrent and refractory acute myeloid leukemia, an d also correlated P-gp expression in leukemia cells with response. METHODS. Thirty-eight eligible patients who were in first recurrence after < 6 months of complete remission (CR) (11 patients), refractory to initial induction therapy or to one attempt at reinduction after recurrence (18 pat ients), in second recurrence (4 patients), or in recurrence after either al logeneic or autologous bone marrow transplantation (5 patients) received ei ther MEC alone (13 patients) or MEC-CSP (25 patients). CSP was given as a l oading dose of 6 mg/kg for 2 hours intravenously (i.v.) starting 2 hours be fore the first dose of etoposide, followed by a continuous i.v. infusion of 18 mg/kg/day for 98 hours. RESULTS. Three of the 13 patients (23%) who received MEC achieved CR, as di d 6 of the 25 patients (24%) who received MEC-CSP. The median remission dur ation for all patients who achieved CR was 149 days (range, 26-466 days), 9 1 days (range, 81-172 days) for the 3 patients who received MEG, and 189.5 days (range, 26-466 days) for the patients treated with MEC-CSP. The median survival for the patients treated with MEC and MEC-CSP was 104 and 72 days , respectively. CONCLUSIONS, No significant association was found between P-gp expression a nd response. No apparent benefit in the CR rate, remission duration, or sur vival was observed with the addition of CSP to MEG. (C) 1999 American Cance r Society.