Chromosome 1 abnormalities in elderly patients with newly diagnosed multiple myeloma treated with novel therapies.

Multiple myeloma is a plasma cell disorder characterized by malignant plasma cell infiltration in the bone marrow, serum and/or urine monoclonal protein and organ damage. The aim of this study was to investigate the impact of chromosome 1 abnormalities in a group of elderly patients (>65 years) with newly diagnosed multiple myeloma enrolled in the GIMEMA-MM-03-05 trial and treated with bortezomib, melphalan and prednisone or bortezomib, melphalan, prednisone and thalidomide followed by bortezomib and thalidomide maintenance. We also evaluated the link between chromosome 1 abnormalities and other clinical, genetic and immunophenotypic features by a multivariate logistic regression model. Interphase fluorescence in situ hybridization on immunomagnetically purified plasma cells and bone marrow multiparameter flow cytometry were employed. A multivariate Cox model showed that chromosome 1 abnormalities, age >75 years and a CD19(+)/CD117(-) immunophenotype of bone marrow plasma cells were independent risk factors for overall survival in elderly patients with newly diagnosed multiple myeloma. Moreover, a detrimental effect of thalidomide, even when administered in association with bortezomib, was observed in patients with abnormal chromosome 1 as well as in those with 17p deletion, while the benefit of adding thalidomide to the bortezomib-melphalan-prednisone regimen was noted in patients carrying an aggressive CD19(+)/CD117(-) bone marrow plasma cell immunophenotype. This trial was registered at www.clinicaltri-als.gov as #NCT01063179.