Abstract 3163: Peripheral blood circulating multiple myeloma cells (CMMCs) correlate with disease burden and can be used to characterize high-risk cytogenetics in newly diagnosed and smoldering myeloma

There is an increasing interest in the ability to dynamically track disease burden and perform molecular subtyping of patients with plasma cell disorders without invasive bone marrow sampling. Circulating multiple myeloma cells (CMMC) have been detected in elevated numbers in the peripheral blood of patients with plasma cell disorders using flow cytometry or circulating cell enrichment platforms. We developed an automated CELLSEARCH® assay to enrich, enumerate, and perform a triplex FISH assay for t(4;14), t(14;16), and del 17p on CMMC (CD138+CD38+, CD45-CD19-) isolated from a 4 mL peripheral blood sample (Gross, et.al. Blood 2011; 118(21):1825). Here we present the enumeration and cytogenetic profiling of CMMC from separate cohorts of patients across the spectrum of plasma cell disorders. The first cohort consisted of newly diagnosed multiple myeloma patients enrolled in the CoMMpass study (ClinicalTrials.gov Identifier: NCT01454297). One or more CMMC per four ml blood were detected in 684/698 (98%) of newly diagnosed myeloma patients with median CMMC count of 413 per 4 mL of blood. CMMC counts decreased significantly from baseline when a remission was achieved due to treatment (p