Author(s): Ahn JS, Jung SH, Yang DH, Bae SY, Kim YK
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 (plasmacytoma, 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 [CI], 21.3-44.1) and 10.7 months (95% CI, 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.