Combination therapy with bortezomib, continuous low-dose cyclophosphamide and dexamethasone followed by one year of maintenance treatment for relapsed multiple myeloma patients.

Combination therapy for longer periods but at low dose might be an effective and tolerable manner to treat patients with relapsed multiple myeloma (MM). We used bortezomib, dexamethasone and low-dose oral cyclophosphamide as an induction regimen, followed by 1 year of maintenance consisting of bortezomib and cyclophosphamide. Relapsed MM patients were treated with six cycles of bortezomib twice weekly, cyclophosphamide 50 mg daily and dexamethasone. Maintenance therapy was given for 1 year. Primary endpoints were toxicity during re-induction and maintenance therapy. Secondary endpoints were response to treatment and progression-free (PFS) and overall survival (OS). This study included 59 patients. Myelosuppression and neuropathy were the most common side effects. Median follow-up was 27·1 (0·46-54·4) months with an overall response of 71%, and a very good partial response or more of 33%. During maintenance, improved responsiveness was observed in 19% of the patients. The median PFS was 18·4 months (range 0·13-43·5) and the median OS was 28·1 months (range 0·13-54·4). In conclusion, our study demonstrates that treatment with bortezomib, dexamethasone and low-dose cyclophosphamide is an effective and manageable regimen. Adding 1 year of maintenance was feasible, with limited side effects and an increased response rate.