Bendamustine, bortezomib and prednisone for the treatment of patients with newly diagnosed multiple myeloma: results of a prospective phase 2 Spanish/PETHEMA trial.

Bendamustine is a bifunctional alkylating agent with proven activity in myeloma. In this study 60 newly diagnosed myeloma patients were given bendamustine plus bortezomib and prednisone in a regimen consisting of one cycle of bortezomib twice weekly for 6 weeks (1.3 mg/m(2) on days 1, 4, 8, 11, 22, 25, 29, and 32), plus bendamustine (90 mg/m(2) on days 1 and 4) and prednisone. The following cycles included bortezomib once weekly. Patients who were transplant candidates proceeded to stem cell collection after four cycles and the transplant was performed after six cycles. Patients who were not candidates for transplantation received up to nine cycles. Forty-two patients were transplant candidates and after six cycles, 50% achieved at least a very good partial response, with 24% having complete responses; 35 proceeded to a transplant, and the complete response rate was 54%. Seventeen patients continued up to nine cycles, and 57% achieved at least a very good partial response, including 26% with complete responses. The 2-year progression-free survival and overall survival rates were 62% and 86%, respectively. The safety profile was manageable, but stem cell mobilization was compromised in 35% of patients. In summary, this combination is effective in untreated patients, with an acceptable toxicity profile, but given the introduction of second-generation novel agents and monoclonal antibodies, the combination will probably be better reserved for relapsing patients, in whom stem cell collection is not needed, while cost-effective combinations with non-cross-resistant drugs continue to represent a medical need. This trial was registered with ClinicalTrials.gov, number NCT01376401.