Patterns of Relapse or Progression After Bortezomib-Based Salvage Therapy in Patients With Relapsed/Refractory Multiple Myeloma

We retrospectively evaluated patterns of relapse or progression after bortezomib-based salvage therapy in patients with multiple myeloma. The transformed relapse or progression was observed in 15 (14.4%) out of 104 patients and their overall survival was extremely short in comparison with isoformed pattern (P < .001). Early diagnosis and new innovative approaches ought to be conducted in these patients. Introduction: Bortezomib-based therapy is commonly used in treatment for relapsed or refractory multiple myeloma (MM). Unfortunately, many patients show relapse or progression in heterogeneous patterns. Patients and Methods: In this study, we retrospectively evaluated patterns of relapse or progression after bortezomib-based salvage therapy in patients with MM and analyzed prognostic significance according to patterns of relapse or progression. One hundred forty-eight patients were treated with bortezomib-based therapy between November 2004 and April 2012. Of these patients, 104 (70.3%) patients relapsed or progressed after bortezomib-based salvage therapy. We divided the patterns of relapse or progression to the 2 groups: (1) the isoform relapse or progression (group A) in 89 (85.6%) patients as disease findings at initiation of bortezomib-based therapy; and (2) transformed relapse or progression (group B) in 15 (14.4%) patients (plasnnacytoma, n = 7; light chain escape, n = 6; and plasma cell leukemia, n = 2) different from initial disease findings. Results: Median overall survival in group A and group B were 32.7 months (95% confidence interval [Cl], 21.3-44.1) and 10.7 months (95% Cl, 2.0-19.4) (P < .001), respectively. Conclusion: MM patients who relapsed or progressed as the transformed pattern for bortezomib-based salvage therapy have an extremely poor prognosis and might require new innovative approaches.