Allogeneic Transplant with Standard Conditioning, Reduced Intensity, or Non-Myeloablative Conditioning Regimen for Multiple Myeloma (MM).

We conducted a retrospective analysis of 58 patients who underwent allogeneic stem cell transplantation at our center from 1994 to 2004. Among these 58 patients, 56 received allogeneic transplant from HLA matched sibling and 2 patients received transplant from a matched unrelated donor. Fourteen patients received standard transplant (ST) using different myeloablative chemotherapy regimens with or without fractionated total body irradiation (FTBI, 9 patients). Thirty four patients underwent tandem transplants (autologous transplant followed by non-myeloablative allogeneic transplant; auto-allo group). Conditioning consisted of melphalan (200mg/m2) prior to the autograft, and TBI (200cGy) as part of non-myeloablative allograft. Ten patients received reduced intensity conditioning (RIC) allograft with fludarabine (25 mg/m2 x 5 days) and melphalan (140 mg/m2). The source of stem cells was bone marrow in 14 patients (ST) and peripheral blood in 44 patients. Median age was 44 yrs for ST group (range 25–53), 51 yrs for auto-allo group (range 38–66) and 48 yrs for RIC group (range 43–64). Median follow up was 2.8 yrs for ST group (range 0.2–13.0), 2.8 yrs for auto-allo group (range 0.2–5.0) and 1.1 yrs for RIC group (range 0.2–3.6). There was a statistically significant difference in overall survival (OS) between the different groups with an observed 2 year OS of 50% in the ST group, 76% in the auto-allo group and 42% in RIC group (P=0.04). Disease free survival (DFS) was also statistically different between the different groups at 2 years: 21% in the ST group, 59% in auto-allo group, and 40% in RIC group (p=0.04). The incidence of severe grade III–IV acute graft versus host disease (GVHD) was less in auto-allo group (6% & 6%), as compared to the RIC group (20% & 10%) and ST group (14% & 14%). 2 year non-relapse mortality rates were 43% in ST, 20% in auto-allo group and 29% in the RIC group, and relapse-related mortality rates were 7% in ST group, 4% in auto-allo group and 29% in the RIC group. There was no statistically significant correlation between GVHD and DFS. Our data suggest an improvement in DFS and OS following tandem auto-non-myeloablative allotransplantation or RIC allotransplantation as compared to standard allogeneic transplant. The better outcome following an auto-allograft approach suggests that cytoreduction prior to an allograft may be important for optimal disease control in MM.