Treatment of IgM-associated AL amyloidosis with the combination of rituximab, bortezomib, and dexamethasone.

IgM-associated AL amyloidosis is a rare clinical entity with distinctive clinical characteristics. Little is known on the applicability of treatment regimens designed for Waldenström's macroglobulinemia (WM) to IgM-AL amyloidosis. Bortezomib is highly effective in AL amyloidosis and the combination of rituximab, bortezomib, and dexamethasone (RBDex) has been successfully tested in WM. Starting in May 2009 we prospectively treated with RBDex 10 patients with IgM-AL amyloidosis. Hematologic response was achieved in 78% of patients, including 3 refractory to previous rituximab. Severe adverse events (grade ≥ 3) were observed in 3 cases. Treatment of IgM-AL amyloidosis with RBDex warrants further investigation in the setting of international clinical trials.