Phase II Study of Bortezomib in Combination with Cyclophosphamide and Rituximab for Relapsed or Refractory Mantle Cell Lymphoma

Background. Relapsed or refractory mantle cell lymphoma (MCL) has a poor prognosis. The best outcome is achieved in patients who have a partial or complete response to salvage treatment and proceed to allogeneic stem cell transplant. Patients and Methods. Twenty-one patients were given a combination regimen of bortezomib, cyclophosphamide, and rituximab at MD Anderson Cancer Center as part of a single-arm, prospective, open-label phase II clinical trial. The median age was 66 years, with a median number of prior treatments of three. Sixty-seven percent had failed intensive chemoimmunotherapy and 43% were intermediate/high risk according to the MCL international prognostic index score, with a median Ki-67 proliferation index of 45% in those who were tested. Results. The rates of overall and complete response achieved were 74% and 42%, respectively, with median progression-free and overall survivals of 9 months and 36.4months, respectively. The regimen's toxicity profile was acceptable; only 25% of the cycles resulted in grade 3 or 4 neutropenia or thrombocytopenia, and only 3% of cycles produced grade 3-4 fatigue. There were no episodes of grade 3-4 neuropathy. Conclusion. The combination of bortezomib with cyclophosphamide and rituximab is an effective and well-tolerated regimen in patients with relapsed/refractory MCL. Because of its low toxicity, future combinations of this regimen with other promising drugs that have different mechanisms of action offer a realistic possibility that may improve outcomes for patients who have MCL.