Retreatment and prolonged therapy with subcutaneous bortezomib in patients with relapsed multiple myeloma: A randomized, controlled, phase III study.

ABSTRACT

OBJECTIVES: This randomized, international, multicenter, open-label phase III study investigated the effects of experimental retreatment with subcutaneous bortezomib plus dexamethasone (VD) followed by prolonged bortezomib therapy vs standard VD retreatment in patients with relapsed/refractory multiple myeloma. METHODS: Patients were randomized (21) to receive either experimental (n = 53) or standard (n = 27) retreatment, stratified by the number of prior therapy lines. RESULTS: The study was terminated prematurely with insufficient enrollment to adequately compare the retreatment therapies; results should be considered descriptive. After a median follow-up of 21.2 and 20.0 months in the experimental and standard arms, respectively, the median progression-free survival (primary endpoint) was 7.2 months (95% confidence interval 5.7-9.0) vs 7.8 months (4.9-11.7). The overall response rate was 66% and 52% for experimental and standard retreatment regimens, respectively. Thrombocytopenia was the most common and most differentially observed grade ≥3 adverse event (experimental 9% vs standard 22%). Any-grade peripheral neuropathies (including peripheral sensory neuropathies) were reported in 23% vs 37% of patients. CONCLUSIONS: This study showed no significant benefit with experimental vs standard VD retreatment therapy. Further investigations are required to determine whether the experimental retreatment regimen is a suitable alternative to the current standard retreatment regimen.