Beta-2-Microglobulin Level Predicts Outcome Following Autologous Hematopoietic Stem Cell Transplantation in Patients With Multiple Myeloma

Despite the widespread use of high-dose therapy combined with autologous hematopoietic stem cell transplantation (autoHSCT), the outcomes of multiple myeloma (MM) treatment remain variable. The aim of this study was to define pretransplantation factors that influence outcomes following autoHSCT in patients with MM. Eighty-one MM patients, aged 51 years (range 31–70 years), undergoing first autoHSCT were included in the analysis. Thirty patients were in complete remission and 51 were in partial remission. The conditioning regimen was based mainly on melphalan (200 mg/m2 intravenous [iv]). The following factors were tested for their prognostic significance: beta-2-microglobulin (B2M), lactate dehydrogenase, monoclonal protein level, bone marrow plasma cell percentage (PL), hemoglobin level, age, interval from diagnosis to autoHSCT, and number of transplanted CD34-positive cells. The transplant-related mortality at day 100 was 3.7% (3/81). The incidence of progression at 9.2 years was 71% for patients with elevated B2M, and 32% for those where B2M was within normal limits (P = .02.) The probability of PFS was decreased for patients with B2M ≥ versus < normal limits (29% vs 68%; P = .02) and PL ≥ versus < 5% (0% vs 45%; P = 0.03). In a multivariate analysis B2M remained the only factor associated with increased risk of progression (relative risk [RR] = 3.3; P = .03) and reduced probability of PFS (RR = 3.3; P = .03). We concluded that B2M level measured at first autoHSCT was a useful predictor for progression and PFS in MM patients.