High dose etoposide-based myeloablative therapy followed by autologous blood progenitor cell rescue in the treatment of multiple myeloma.

Abstract

A number of studies have demonstrated that high dose chemotherapy, with or without radiotherapy, with autologous marrow and/or peripheral blood progenitor cell support can result in improved overall and complete response rates in patients with multiple myeloma, and a minority of patients become long term survivors. Based on their favorable experience with high dose etoposide-based regimens in patients with Hodgkin's disease and non-Hodgkin's lymphoma, the authors explored the use of these regimens prior to autologous progenitor cell rescue in patients with multiple myeloma. Thirty-four patients (median age, 49 years; range, 38-65) with multiple myeloma who were responsive to standard chemotherapy were enrolled in this study. Blood progenitor cells were collected after treatment with cyclophosphamide at a dose of 4 g/m2 followed by granulocyte-colony stimulating factor (G-CSF) at a dose of approximately 10 micrograms/kg/day subcutaneously, and the collection continued daily until the target number of mononuclear cells had been obtained. The preparative regimen consisted of fractionated total body irradiation (FTBI) of 1200 centigray in 10 fractions on Day -8 to Day -5, etoposide 60 mg/kg intravenously (i.v.) on Day -4, and cyclophosphamide 100 mg/kg i.v. on Day -2. Day 0 was the day of progenitor cell infusion. Patients who were older than 50 years or had received prior radiation therapy that precluded FTBI received carmustine 15 mg/kg i.v. or lomustine 15 mg/kg orally on Day -6 rather than FTBI. G-CSF (5 micrograms/kg/day) was begun the day after progenitor cell infusion and continued until engraftment. Recovery of granulocytes to 500/microL occurred at a median of 9 days (range, 7-13), and platelet recovery to 20,000/microL occurred without transfusion at 9 days (range, 6-88) after progenitor cell infusion. Thirty-two patients were evaluable for response. Eleven patients (34%) achieved a complete remission, 17 (53%) achieved a partial remission, and 4 (13%) had stable disease following high dose therapy and progenitor cell rescue. The actuarial event free survival at 4 years for the entire group was 26%, and overall survival was 36%. The median time to progression of disease was 13 months (range, 2-42). Two patients died of regimen-related toxicity, one of venoocclusive disease of the liver and the other of multiorgan failure. In a multivariate analysis, only the extent of prior therapy was a significant prognostic factor for event free survival, and no significant factors were identified for overall survival. High dose etoposide-based myeloablative regimens followed by autologous blood progenitor cell rescue are relatively well tolerated and effective for the treatment of multiple myeloma, and a minority of patients become long term disease free survivors.