Effect of melphalan 140 mg/m2vs 200 mg/m2on toxicities and outcomes in multiple myeloma patients undergoing single autologous stem cell transplantation-a single center experience

Although melphalan at a dose of 140 mg/m(2) (MEL140) is an acceptable conditioning regimen for autologous stem cell transplantation (ASCT) in multiple myeloma (MM) patients, very few studies compared it to the most commonly used dose of 200 mg/m(2) (MEL200). A retrospective review of records of MM patients (2001-2010) identified 33 patients who received MEL140 and 96 patients who received MEL200. As expected, significantly higher percentage of patients in the MEL140 arm were65 years or had cardiac ejection fraction50%, had Karnofsky score80, or had creatinine2 at the time of ASCT (P≤.01). There were no significant differences in incidence of treatment related mortality and morbidity. At a median follow-up of 74 months from ASCT, there were no significant differences in relapse free survival (RFS) and overall survival (OS) between the two groups. Similar proportion had myeloma status improve to ≥VGPR at 3 months post-ASCT. Usage of post-ASCT maintenance was similar. In multivariate cox proportional hazards model, only disease status of ≥VGPR at the time of ASCT significantly improved RFS (P=.024), but not OS (P=.104). In conclusion, MM patients who received MEL140 had similar long-term outcomes to MEL200 patients despite their older age and co-morbidities.