Comparable kinetics of myeloablation between fludarabine/full-dose busulfan and fludarabine/melphalan conditioning regimens in allogeneic peripheral blood stem cell transplantation

Fludarabine was utilized in the conditioning regimen of 30 adult patients undergoing an allogeneic hematopoietic stem cell transplant. In 18 patients it was combined with full-dose busulfan (FluBu) as a myeloablative regimen and in 12 cases with melphalan (FluMel) as a reduced intensity conditioning (RIC) regimen. Patients in the FluBu group were younger than in the FluMel group (P=0.03). Of 30 patients, 24 received peripheral blood stem cells (PBSC) whereas six patients in the FluBu group received bone marrow cells. The hematological toxicity of each regimen was evaluated by analyzing the kinetics of the neutropenia induced by preparative regimens and the time to recovery of the absolute neutrophils count (ANC) and platelets post transplantation. In PBSC transplants, the median day of severe neutropenia (<500 ANC/microl) occurred on day +6 after the FluBu regimen and on day +3 after FluMel (P=ns), whereas both groups had a duration of severe neutropenia of 9 days and a comparable time for ANC and platelet engraftment. Extra-hematological toxicities were also comparable in the two groups. These findings suggest that the hematological and extra-hematological toxicities induced by fludarabine/full-dose i.v. busulfan are similar to those induced by a standard RIC regimen such as fludarabine/melphalan.

Prolonged responses after autologous stem cell transplantation in African-American patients with multiple myeloma

Multiple myeloma (MM) has a double incidence in African-American (AA) than in non-AA patients and previous studies have shown a higher mortality in the former patient population. Here, we retrospectively analyzed the results of autologous stem cell transplantation (ASCT) in 38 AA and 32 non-AA consecutive patients. The two groups were comparable at diagnosis for age, stage of the disease, cytogenetic abnormalities, beta(2) microglobulin and albumin blood levels, and plasma cell marrow infiltration. The rates of complete and partial response observed in AA and non-AA patients after induction chemotherapy (9 and 42 vs 13 and 33%) and at 2 months (31 and 25 vs 30 and 20%) following ASCT were similar. At 6 months after ASCT, a greater relapse rate was observed in non-AA patients (P=0.009). At a median follow-up of 26 months, AA patients had a greater event-free survival (P=0.02) than non-AA patients, whereas overall survival was comparable in the two groups. The initial finding that AA patients with MM, compared to non-AA patients, had more prolonged responses and comparable survival after ASCT suggests that intensified chemotherapy is equally effective in patients of various ethnicities.