Single-centre experience with nonmyeloablative allogeneic stem cell transplantation in patients with multiple myeloma: prolonged remissions induced.

BACKGROUND

The role of allogeneic stem cell transplantation in multiple myeloma is not yet established.

METHODS

We retrospectively evaluated the outcome of nonmyeloablative allogeneic stem cell transplantation (NMA) in patients with multiple myeloma treated at the Department of Haematology of the University Medical Centre Utrecht. Thirty-six patients received NMA as part of the first-line treatment; 23 patients as part of salvage therapy. Conditioning regimen was low-dose total body irradiation (TBI, 2 Grays) only; fludarabine was added in patients without previous autologous stem cell transplantation and patients with matched unrelated donors received antithymocyte globulin in addition to fludarabine and TBI.

RESULTS

Following NMA overall response increased from 84 to 90%, complete remission rate from 15 to 32%. As part of first-line treatment NMA induced complete remission in 50% of patients vs one patient (4%) treated for relapsed multiple myeloma. Median progression-free survival was 26 months (13 months for the salvage group, 38 months for the 'upfront' patients). Median overall survival has not been reached yet. The achievement of complete remission following NMA as part of first-line treatment was associated with prolonged progression-free and overall survival. Major toxicities were acute and chronic graft-vs-host disease occurring in 64% (23% grade 3-4) and in 54% (49% extensive) patients, respectively. Seven patients (12%) died from nonrelapse mortality, five patients (9%) directly related to toxicity of NMA.

CONCLUSION

NMA in multiple myeloma is feasible, is associated with acceptable nonrelapse mortality and may induce prolonged complete remission. In pretreated patients the result of NMA is disappointing which urges new strategies.