The efficacy and safety of bortezomib and dexamethasone as a maintenance therapy in patients with advanced multiple myeloma who are responsive to salvage bortezomib-containing regimens

Abstract

BACKGROUND: Although treatment for multiple myeloma (MM) has considerably improved in the past decade, MM continues to be an incurable hematological malignancy that causes most patients to eventually relapse and die from their illness. Thus, the identification of effective salvage strategies remains a priority. METHODS: In this trial, the authors evaluated the safety and efficacy of bortezomib and dexamethasone [V: on days 1 and 15 (1.3 mg/mq); D: on days 1-2 and 15-16, every 28-day cycle until progression (20 mg/d)] as maintenance therapy (MT) in patients with advanced MM who responded to salvage therapy that used a bortezomib-containing regimen. RESULTS: Forty-nine MM patients were enrolled in this study between October of 2004 and April of 2008. All patients who were included in this study were responsive to a prior salvage therapy with bortezomib and had a measurable disease. The bortezomib and dexamethasone MT improved the quality of responses to complete remission in 4 patients and very good partial response in 3 patients. In addition, 10 patients experienced at least a 50% improvement in their symptoms. The median time to progression (TTP) was 16 months with a progression-free survival of 61% after 1 year. The overall response after 1 year was 76%, and the cumulative incidence of death due to disease progression, which was adjusted for competitive risk events, was 14%. Non-dose-limiting toxicities included neuropathy (predominantly grade 1), herpes zoster reactivation, pneumonia, and gastrointestinal affections (constipation and diarrhea). Three patients developed grade 2 neuropathy, which required a bortezomib dose reduction to 1.0 mg/mq. No grade 3 or 4 toxicities were recorded. CONCLUSIONS: The use of bortezomib and dexamethasone as MT in advanced MM was effective and well tolerated. The twice-monthly bortezomib infusion appeared to reduce the incidence of grade 3 and 4 neuropathies in comparison to similar experiences in other settings. Cancer 2011;117:1884-1890. © 2010 American Cancer Society.