This largest study to date of CANOMAD patients revealed that one third harbored an overt hematologic malignancy, consisting mainly in WM.
IVIg and rituximab-based regimens were the most effective therapies with a 50% response rate
CANOMAD (chronic ataxic neuropathy, ophthalmoplegia, IgM paraprotein, cold agglutinins and disialosyl antibodies) is a rare syndrome characterized by chronic neuropathy with sensory ataxia, ocular and/or bulbar motor weakness, in the presence of a monoclonal IgM reacting against gangliosides containing disialosyl epitopes. Data regarding associated hematologic malignancies and effective therapies in CANOMAD are scarce. We conducted a French multicenter retrospective study that included 45 patients with serum IgM antibodies reacting against disialosyl epitopes in the context of evocating neurological symptoms. Main clinical features were sensitive symptoms (ataxia, paresthesia, hypoesthesia) (n=45, 100%), motor weakness (n=18, 40%), ophthalmoplegia (n=20, 45%) and bulbar symptoms (n=6, 13%). Forty five percent of the cohort had moderate to severe disability (modified Rankin score, 3-5). Cold agglutinins were identified in 15 (34%) patients. Electrophysiological studies showed a demyelinating or axonal pattern in respectively 60 and 27% of cases. All patients had serum monoclonal IgM gammopathy (median, 2.6 g/L; range, 0.1-40). Overt hematologic malignancies were diagnosed in 16 patients (36%), most frequently Waldenström macroglobulinemia (n=9, 20%). Forty-one patients (91%) required treatment for CANOMAD. Intravenous immunoglobulins (IVIg) and rituximab-based regimens were the most effective therapies with respectively 53 and 52% of partial or better clinical responses. Corticosteroids and immunosuppressive drugs were largely ineffective. Although more studies are warranted to better define the optimal therapeutic sequence, IVIg should be proposed as the standard of care for first-line and rituximab-based regimens for second-line treatment. These compiling data argue for CANOMAD to be included in neurological monoclonal gammopathy of clinical significance.