A phase II trial of small-dose bortezomib, lenalidomide and dexamethasone (sVRD) as consolidation/maintenance therapy in patients with multiple myeloma.

PURPOSE: Consolidation/maintenance therapy induces deep remission in patients with multiple myeloma (MM); however, the most suitable regimen has been under investigation. The combination therapy with bortezomib, lenalidomide and dexamethasone (VRD) is a powerful regimen for relapsed/refractory as well as newly diagnosed MM as an induction therapy. However, severe adverse events (AEs) may become a problem when VRD is introduced without dose reduction as a consolidation/maintenance therapy.

METHODS: In this single-arm phase II study, we evaluated the efficacy of small-dose VRD regimen (sVRD) in the consolidation/maintenance setting. Sixteen patients who had partial response (PR) or better after any induction therapy were enrolled. Patients received at least six 28-day cycles of subcutaneous bortezomib (1.3 mg/m(2) on days 1 and 15), lenalidomide (10 mg on days 1-21) and dexamethasone (40 mg on days 1, 8, 15 and 22).

RESULTS: The overall response rate and the complete response (CR) rate were 100 and 43.8 %, respectively. In particular, one patient with CR and two patients with very good PR at enrollment achieved stringent CR during 6 courses of sVRD. With a median follow-up time of 29.4 months, the median progression-free survival (PFS) and overall survival (OS) were not reached, while the PFS and OS rates at 2.5 years were 66.6 and 77.3 %, respectively. Univariate analysis demonstrated that disease progression as a reason for discontinuation of sVRD had a negative impact on OS. There were no grade 3 or 4 hematologic or nonhematologic AEs.

CONCLUSION: Our sVRD regimen as a consolidation/maintenance therapy was highly effective and well tolerable.