Natural History and Outcomes of Asymptomatic IgM Monoclonal Gammopathy

Abstract Waldenstrom's macroglobulinemia (WM) is a distinct clinical entity defined by the presence of a serum monoclonal IgM and bone marrow (BM) infiltration of ≥10% lymphoplasmacytic cells. Asymptomatic (smoldering) WM (aWM) is defined by the presence of serum IgM ≥3 g/dL and/or ≥10% BM lymphoplasmacytic infiltration but no evidence of end-organ damage (symptomatic anemia/cytopenias, constitutional symptoms, lymphadenopathy, hepatosplenomegaly or IgM-related symptoms such as hyperviscosity, severe neuropathy etc) that can be attributed to the underlying clonal disorder (Kyle et al; Blood 2012). IgM monoclonal gammopathy of undetermined gammopathy (MGUS) is defined by the presence of a monoclonal IgM of All patients were diagnosed and followed in the Department of Clinical Therapeutics (Athens, Greece) since 1995 and had BM biopsies available. Patients who presented with IgM-related complications (neuropathy, Schnitzler syndrome, IgM related amyloidosis etc) were not included. At the time of diagnosis of the IgM gammopathy, median age of all subjects was 71 years (range 25-86), 76% had IgMκ and 24% IgMλ; only one had a biclonal gammopathy (IgM and IgG). Median IgM was 1024 mg/dL (range 104 - 5320) and the monoclonal spike in the SPEP was 0.84 g/dL (ranging According to the definition by Kyle et al, 62 (61%) subjects had aWM and 41 (39%) IgM MGUS. Patients with aWM had higher M-protein (median 1.24 vs 0.55 g/dL) and more often monoclonal protein ≥1 g/dl (58% vs 13%, p In conclusion, patients with aWM should be followed without treatment unless symptoms develop. Bone marrow infiltration ≥50% and a hemoglobin Download : Download high-res image (64KB) Download : Download full-size image Figure . Disclosures Kastritis: Amgen: Research Funding; Takeda: Honoraria; Genesis: Honoraria; Janssen: Honoraria, Research Funding. Terpos: Genesis/Celgene: Honoraria, Other: DMC member, Research Funding; BMS: Honoraria; GSK: Honoraria; Abbvie: Honoraria; Takeda: Honoraria, Other: SC member; Janssen: Honoraria, Research Funding; Amgen: Honoraria, Other: SC member, Research Funding. Dimopoulos: Novartis: Consultancy, Honoraria; Genesis Pharma: Research Funding; Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Onyx Pharmaceuticals, an Amgen subsidiary, Takeda Oncology: Consultancy, Honoraria, Other: Advisory Committee: Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Onyx Pharmaceuticals, an Amgen subsidiary, Takeda Oncology.