Successful mobilization of peripheral blood stem cells in heavily pretreated myeloma patients with G-CSF alone

Abstract

We investigated the feasibility of mobilizing peripheral blood stem cells (PBSC) with G-CSF alone in 24 patients with multiple myeloma. The median age was 53 years (range 33-62). All patients had stage II/III disease and responded to standard first-line (n = 6) or salvage chemotherapy (n = 18). The median number of previous chemotherapy cycles was 7 (4-18) and the median number of prior melphalan-cycles was 6 (0-14). Nine (35%) patients had experienced prior radiation therapy. The patients received either 10 microg/kg G-CSF (n = 18) or 24 microg/kg G-CSF (n = 7, including one patient with previous 10 microg/kg G-CSF stimulation) daily s.c. for 5 or more consecutive days until completion of harvesting, starting apheresis on the fifth day. G-CSF treatment was well tolerated, with only slight bone pain in half of the patients (51%). After a median of three (range 1-7) apheresis procedures, medians of 3.8 (0.3-17) x 10(6) CD34+ cells/kg, 8.5 (4.5-24) x 10(8) MNC/kg, 2.9 (0.6-39.4) x 10(4) CFU-GM/kg, and 5.6 (0.9-49) x 10(4) BFU-E/kg were harvested. Three patients (12%) with extensive melphalan pretreatment failed the target collection of at least 2.0 x 10(6) CD34+ cell/kg. Pretreatment with six or more cycles of melphalan yielded a smaller number of CD34+ cells than pretreatment with fewer than six cycles (2.5 vs 5.3 x 10(6)/kg; p = 0.001). Nineteen patients underwent high-dose chemotherapy consisting of either total marrow irradiation (9 Gy)/busulfan (12 mg/kg) and cyclophosphamide (120 mg/kg) (n = 10), or busulfan (14 mg/kg)/cyclophosphamide (120 mg/kg) (n = 5), or tandem melphalan (200 mg/m2). The median time for granulocyte (> 1.0/nl) and platelet (> 50/nl) recovery was 10 and 14 days (ranges 7-12 and 8-40), respectively. G-CSF alone is a safe, alternative approach to mobilizing sufficient PBSC in patients with multiple myeloma and allows an exact prediction of harvest time. G-CSF-mobilized PBSCs ensure rapid engraftment after myeloablative therapy. Melphalan treatment should be avoided in patients who are candidates for high-dose chemotherapy.