High-dose idarubicine, busulphan and melphalan as conditioning for autologous blood stem cell transplantation in multiple myeloma. A feasibility study

Extensive studies have tested the clinical impact of double and triple sequ ential transplants as front-line therapy in MM, following the suggestion th at dose escalation can overcome the marked drug resistance characteristic o f this disease, but the superiority of such approaches vs one single transp lant has still to be demonstrated. The aim of our study was to evaluate the feasibility and efficacy of high-dose idarubicine intensification of a sta ndard busulphan-melphalan conditioning regimen in MM. Twenty-eight patients (median age 55 years) with sensitive disease received PBSCT after high-dos e idarubicine combined with busulphan and melphalan and followed by s.c. rh G-CSF until PMN recovery. The most severe toxicity was represented by oral mucositis which resolved with hemopoietic reconstitution. Overall response and CR rate were 52% and 40%, respectively. Currently, 36 patients are aliv e and 19 are progression-free a median of 20 months (12-36) from transplant . The 3-year projected probability of progression-free survival for patient s transplanted after first-line treatment is 60%. The combination of Ida/Bu /Melph appears a promising alternative regimen for PBSCT in myeloma, with l ow transplant-related toxicity and fast hematological recovery. Long-term f ollowup and a prospective randomized study, now ongoing, will probably clar ify whether an idarubicine-intensified regimen will result in superior outc omes to conventional conditioning and even be comparable to a double consec utive transplant program.