High dose chemoradiotherapy and autologous blood stem cell transplantation in multiple myeloma

We report the results of peripheral blood stem cell (PBSC) collection performed after priming with a semi-intensive CHOP regimen in 70 patients with aggressive multiple myeloma (MM). Forty-one of the 44 previously untreated patients compared to 17 of the 26 patients with a refractory disease yielded stem cells enough for autotransplantation. Phenotypic and genotypic studies of collected mononuclear cells, even performed after depletion of monocytes and/or of T lymphocytes, did not reveal contamination by tumor plasma cells or clonal B cell precursors in any studied case. Forty-eight of the 58 patients with successful PBSC collection have been presently treated by high dose therapy followed by autologous blood stem cell transplantation (ABSCT). Among the 43 patients who received a regimen including total body irradiation, four died within six months after the autograft. All remainders responded and most often achieved an impressive tumor mass reduction. Ten relapsed and four died from disease progression. Nine to 70 months (median: 35 months) after blood stem cell collection, 29 patients are either in apparent complete remission or with a state of stable residual disease, most often minimal. Blood stem cell autograft was successful in all evaluable patients and the kinetic of hematologic recovery was roughly related to the amount of reinfused CFU-GM (2.1 to 50 x 10(4)/kg). Median delays for granulocytes greater than 500/mm3 and platelets greater than 25,000/mm3 were 15 days and 20 days, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)