Therapeutic effect of bortezomib for primary plasma cell leukemia followed by auto/allo stem cell transplantation

Plasma cell leukemia (PCL) is a rare disease that represents approximately 4% of plasma cell malignant disorders. PCL consists of two variants: primary PCL presents in patients with no previous history of multiple myeloma, while secondary PCL consists of a leukemic transformation in a previously recognized multiple myeloma. Primary PCL is an extremely resistant, rapidly progressive, fatal disease, with a median overall survival of 6.8 months. There is no standard therapeutic strategy, because no treatment option has been prospectively evaluated. We describe a successful case of newly diagnosed primary PCL, treated with a regimen that included bortezomib, followed by auto stem cell transplantation and nonmyeloablative allogeneic stem cell transplantation. Our patient has maintained remission status for over 12 months since undergoing the allogeneic stem cell transplantation. This strategy is promising for PCL, which, though an extremely resistant disease, may become curable.