Comparison of high-dose melphalan with a more intensive regimen of thiotepa, busulfan, and cyclophosphamide for patients with multiple myeloma

BACKGROUND. High-dose chemotherapy (HDC) with autologous stem cell transplantation (ASCT) as part of the initial treatment regimen improves progression-free survival (PFS) and overall survival (OS) for patients with multiple myeloma. The optimal preparative regimen for patients with multiple myeloma has yet to be defined. In the current study, the authors compared the outcomes associated with high-dose melphalan (HDM) and a more intensive regimen of thiotepa, busulfan, and cyclophosphamide (TBC) in patients with multiple myeloma. METHODS. One hundred eighty-six patients with newly diagnosed multiple myeloma (median age, 51 years) received HDC with ASCT for consolidation of first remission (n = 108) or for treatment of primary refractory disease (n = 78). Seventy patients had a large tumor mass at the time of diagnosis. The preparative regimen consisted of TBC for 97 patients and HDM for 89 patients. Patients in the TBC group were younger and had more advanced disease stage at diagnosis and at the time of ASCT compared with patients in the HDM group. RESULTS. The response rates (complete response [CR] and partial response [PR]) were similar in the TBC group (overall response rate, 66%; CR rate, 17%; PR rate, 49%) and the HDM group (overall response rate, 69%; CR rate, 28%; PR rate, 41%). PFS and OS were similar in both groups. A proportional hazards regression model revealed that Durie-Salmon disease stage at diagnosis and having received three or more previous treatment regimens were the only factors that predicted PFS; the type of preparative regimen did not influence outcome. CONCLUSIONS. The results of the current study indicate that the use of a more intensive regimen did not improve results compared with HDM in patients with multiple myeloma. HDM should continue to be considered the standard preparative regimen for patients with myeloma. (C) 2004 American Cancer Society.