SUCCESSFUL MOBILIZATION OF PERIPHERAL-BLOOD STEM-CELLS IN HEAVILY PRETREATED MYELOMA PATIENTS WITH G-CSF ALONE

We investigated the feasibility of mobilizing peripheral blood stem ce lls (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 d isease and responded to standard first-line (n =6) or salvage chemothe rapy (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 patie nts received either 10 mu g/kg G-CSF (n = 18) or 24 mu g/kg G-CSF (n = 7, including one patient with previous 10 mu g/kg G-CSF stimulation) d aily s.c. for 5 or more consecutive days until completion of harvestin g, starting apheresis on the fifth day. G-CSF treatment was well toler ated, 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. 3) 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 th e target collection of at least 2.0 x 10(6) CD34 + cell/kg. Pretreatme nt with six or more cycles of melphalan yielded a smaller number of CD 34+ cells than pretreatment with fewer than six cycles (2.5 vs 5.3 x 1 0(6)/kg; p = 0.001). Nineteen patients underwent high-dose chemotherap y consisting of either total marrow irradiation (9 Gy)/busulfan (12 mg /kg) and cyclophosphamide (120 mg/kg) (12 = 10), or busulfan (14 mg/kg )/cyclophosphamide (120 mg/kg) (n = 5), or tandem melphalan (200 mg/m( 2)). The median time for granulocyte (>1.0/nl) and platelet (>50/nl) r ecovery was 10 and 13 days (ranges 7-12 and 8-40), respectively. G-CSF alone is a safe, alternative approach to mobilizing sufficient PBSC i n patients with multiple myeloma and allows an exact prediction of har vest time. G-CSF-mobilized PBSCs ensure rapid engraftment after myeloa blative therapy. Melphalan treatment should be avoided in patients who are candidates for high-dose chemotherapy.