Advances in the Treatment of Paraproteinemic Neuropathy

Purpose of review Several advances have been made on the pathogenesis and therapy of neuropathies associated with paraproteinemia (monoclonal gammopathy). It is important for the neurologist to understand the pathogenetic relevance of this association especially when the hematological disease does not require per se any therapy. Recent findings Treatment of the neuropathy in patients with malignant paraproteinemia is mainly addressed by the hematologist while the neurologist is mainly involved in the initial diagnosis and in deciding whether the neuropathy is caused by the disease or by the chemotherapy used for the disease. There is little evidence that the neuropathy is caused by the hematological condition in patients with IgG or IgA monoclonal gammopathy of undetermined significance (MGUS) unless there is an evidence of a reactivity of the paraprotein with nerve or evidence of its presence in the nerve. Patients with a chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)-like presentation should be treated as CIDP while there is no evidence that immune or chemotherapy may be effective in the other patients. In most patients with IgM paraproteinemia, that is usually a MGUS or an indolent Waldenström's macroglobulinemia, the neuropathy is induced by an immune reactivity of the paraprotein with nerve and particularly with the myelin-associated glycoprotein. There are now consistent data also from controlled studies that the anti-CD20 monoclonal antibody rituximab may improve the neuropathy in these patients. POEMS syndrome is a severe condition characterized by a disabling neuropathy whose prognosis has improved in the last few years with therapies against the proliferating plasma cell clone or vascular endothelial growth factor including local radiotherapy and chemotherapy followed by autologous stem cell transplantation. Other therapies are also available for patients not eligible or resistant to transplantation, including lenalidomide and possibly thalidomide or bortezomib. Summary Several new therapies are now available for patients with paraproteinemic neuropathy consistently improving the prognosis of these neuropathies. In most instances, however, their efficacy needs to be confirmed in controlled trials.