Previous studies have shown that
retreatment of relapsed/refractory
multiple myeloma (MM) with a second course of
bortezomib therapy could be effective in heavily pre-treated patients. In this study, the results of a multicentre, retrospective survey were reported involving patients in Switzerland with MM who responded to initial
bortezomib therapy; 43 patients were enrolled and 42 were evaluated for response. The overall response rate (complete response [CR] + near CR [nCR] + partial response [PR]) to
bortezomib retreatment was 64.3%, and the clinical benefit rate (CR + nCR + PR + stable disease) for
retreatment was 83%. The response rate to
bortezomib retreatment in the subgroup with a first treatment-free interval (TFI) >6 months was higher than that in the subgroup with first TFI ≤6 months (74.1% vs. 46.7%) and lower in patients who received concomitant
dexamethasone with
bortezomib retreatment (57.1% vs. 78.6%). The median overall survival (OS) from first diagnosis of MM was 9.3 years, and after
retreatment with
bortezomib the median OS was 1.7 years. In total, 85.7% of patients who achieved CR or nCR with initial
bortezomib treatment achieved CR or nCR with
retreatment.
Bortezomib as
retreatment was well tolerated, and the safety profile was consistent with previous studies of
bortezomib in relapsed MM. The most common
adverse drug reaction attributed to
bortezomib was
peripheral neuropathy in 5 patients. In conclusion,
bortezomib retreatment was a well-tolerated, effective therapeutic option for relapsed MM patients in the Swiss clinical setting who have previously responded to
bortezomib, particularly for those who experienced an initial TFI of >6 months.