Chromosome 1 abnormalities in newly diagnosed elderly multiple myeloma patients 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 (>65 years) newly diagnosed Multiple Myeloma patients, enrolled in the GIMEMA-MM-03-05 trial and treated with bortezomib, melphalan and prednisone vs 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. By a multivariate Cox model, chromosome 1 abnormalities, age >75 and CD19+/CD117- bone marrow plasma cells immunophenotype emerged as independent risk factors for Overall Survival in elderly, newly diagnosed multiple myeloma patients. Moreover, a detrimental effect of thalidomide, even when administered in association with bortezomib, was observed in abnormal chromosome 1 as well as (17p)deleted patients, while the benefit of thalidomide addiction to the bortezomib-melphalan-prednisone regimen was noted in patients carrying an aggressive CD19+/CD117- bone marrow plasma cells immunophenotype. This trial was registered at www.clinicaltrials.gov as #NCT01063179.