A novel regimen combining high dose cytarabine and bortezomib has activity in multiply relapsed and refractory mantle cell lymphoma - long-term results of a multicenter observation study.

Salvage therapy for patients with mantle cell lymphoma (MCL) remains a challenge. The clinical course is characterised by increasing resistance to conventional chemotherapy and a dismal long-term outcome. On the basis of studies demonstrating synergy in vitro, eight heavily pretreated patients (median age 65 years) with advanced stage MCL were individually treated with a novel combination protocol consisting of the proteasome inhibitor bortezomib (1.5 mg/m(2); Days 1 and 4), high-dose cytarabine (750-2000 mg/m(2); Days 2 and 3) and dexamethasone (40 mg daily; Days 1-4). Rituximab (375 mg/m(2)) was added in patients not refractory to prior rituximab-containing regimens. Treatment was repeated in 3-week intervals or postponed until hematologic recovery for up to four planned cycles. Toxicity consisted mainly of Grade 3/4 hematotoxicity, which occurred in all patients. Median treatment interval was 31 days. Objective responses were observed in four (50%) of eight patients, including two complete remissions. Median progression free and overall survival were 5 and 15.5 months, respectively. The combination of bortezomib and a high-dose cytarabine-containing regimen has activity in heavily pretreated patients with relapsed or refractory MCL.