Predictive factors for a successful mobilization of peripheral blood CD34(+) cells in multiple myeloma

We analyzed the prognostic factors for a successful mobilization and periph eral blood stem cell collection in a series of 57 consecutive patients with multiple myeloma (MM); a new scoring system to predict an adequate mobiliz ation in this subset of patients was also constructed. A total of 221 apher eses were performed in 57 patients with MM. The median time from diagnosis to mobilization was 12 months (range 4-120). Only one line of chemotherapy was administered before mobilization to 36 patients and two or more to 21. The median number of alkylating chemotherapy cycles was 6 (2-33). Two patie nts were mobilized in complete remission, 32 in partial response, and 23 in stable/progressive disease. Significant adverse prognostic factors for col lecting 2.5x10(6) CD34(+)cells/kg or more were: a period of at least 12 mon ths from diagnosis, at least six cycles of alkylating agents, and a plasma cell infiltration of 20% or more prior to mobilization. Patients with three risk factors had a probability of only 0.38 (95% CI 0.3-0.9) for adequate mobilization. Ten patients failed to mobilize; a period from diagnosis of 1 2 months or more and female sex were unfavorable factors. Patients with two risk factors had a probability of 0.50 (95% CI 0.2-0.8) for failing the mo bilization procedure. These findings indicate that MM patients must be mobi lized early in the course of the disease, with minimal disease burden befor e severe hematopoietic progenitor cell injury due to cumulative therapy.