Mel-140 and TBI vs Mel-200 Prior to Autologous Peripheral Blood Stem Cell Transplantation for Multiple Myeloma - a Single Institution Experience.

Between 1991–98, twenty-nine patients with myeloma received Mel-140 and TBI (960 cGy) followed by Cytoxan mobilized autologous PBSCT. Between 1998 and April, 2004, 41 patients received Mel-200 alone followed by autologous PBSCT. The two groups were comparable regarding age, gender, stage, number of prior regimens and ß2 microglobulin at diagnosis. However, the Mel-200 group had greater proportion of patients with IgG myeloma (78% vs 38%) and shorter time from diagnosis to transplant (301 days vs 581 days). Results: Neutrophil engraftment was similar in the two groups. However, platelet engraftment, transfusion requirements, length of stay and number of days on antibiotics were worse in the Mel-TBI group. The complete and very good partial responses were high in both groups Mel TBI 58.6% vs Mel-200 56% (p=0.81). Median overall survival (OS) was 3.5 years and 3.8 years for Mel TBI and Mel-200 groups, respectively (p=0.75). Event-free survival (EFS) was 1.9 years and 2.3 years, respectively (p=0.88). Survival after relapse post-PBSCT was short, median 1.1 and 1.8 years, respectively. We present here the results of two groups of myeloma patients treated consecutively in a single institution. The Mel-200 patients had a higher proportion of IgG myeloma and were transplanted earlier in the phase of their disease. As expected, regimen-related toxicities were higher in the Mel-TBI group. The response rates, OS, and EFS were similar. These results are in keeping with published reports of prospective randomized studies. Mel-200 is now the standard conditioning regimen for autologous transplant for myeloma.