Introduction: Bortezomib (Velcade) is a proteasome inhibitor that has shown important clinical efficacy either as a single agent or in combination with other cytostatic agents in multiple myeloma (MM). In the present protocol, bortezomib was combined with other active substances like bendamustine and prednisone (BPV), in order to assess the efficacy and toxicity of the combination therapy in patients with relapsed or refractory MM.
Methods: Between January 2005 and December 2011, 78 patients with relapsed or refractory MM were treated with bendamustine 60 (-120) mg/m(2) on days 1 and 2, bortezomib 1.3 mg/m(2) on days 1, 4, 8 and 11, and prednisone 100 mg on days 1, 2, 4, 8 and 11. The median number of prior therapies was 2 with a wide range of 1-9. Thirty-three patients had pre-existing severe thrombocytopenia and/or neutropenia (WHO grade 3 or 4).
Results: A median number of two (range 1-7) BPV treatment cycles were given to the patients. The majority of the patients (n = 54; 69 %) responded after at least one cycle of chemotherapy with 3 CR, 10 nCR, 10 VGPR and 31 PR. Median PFS and OS for patients without severe hematological toxicities due to previous treatments (n = 45) were 11 and 50 months, respectively. Outcome for these patients was significantly better than that for patients with severe hematological toxicities (grade 3 or 4, n = 33) with a PFS, and OS of 3 months (p < 0.05) and 5 months (p < 0.001), respectively. The regimen was well tolerated with few significant side effects in patients without severe hematological toxicities due to previous treatments. These results indicate that the combination of bortezomib, bendamustine and prednisone is well tolerated in patients with relapsed or refractory MM.