Objectives: In vitro studies have shown synergistic antimyeloma effects with the combination of bortezomib and alkylating agents. Combinations of bortezomib, cyclophosphamide, and dexamethasone are rational with the prospect of superior antitumor activity with independent toxicity.
Methods: Between December 2004 and April 2007, we treated 44 patients with relapsing multiple myeloma with the combination of bortezomib 1.3 mg/m intravenously on days 1, 4, 8, 11; dexamethasone 20 mg/m orally daily for 4 days beginning on days 1, 9 and 17; and cyclophosphamide 70 mg/m orally twice daily for 4 days. A second course was given 1 month later.
Results: Clinical response was observed in 32 patients (73%) including 26 with disease in partial remission (59%), and 6 with disease in complete remission (14%). Side effects were uncommon and mild, except for grade 3 thrombocytopenia in 15%, infection in 5% and constipation in 2% of patients. The median remission time of responding patients was 10 months that contributed to significantly longer median survival for patients with responsive disease (33 mo) than for those with unresponsive disease (12 mo) (P < 0.01).
Conclusion: Bortezomib-cyclophosphamide-dexamethasone was an effective, well-tolerated combination for the treatment of relapsing multiple myeloma.