Weekly versus twice weekly bortezomib given in conjunction with rituximab, in patients with recurrent follicular lymphoma, mantle cell lymphoma and Waldenström macroglobulinaemia.

The combination of bortezomib and rituximab was evaluated in patients with mantle cell lymphoma (MCL), follicular lymphoma (FL) and Waldenström macroglobulinaemia (WM), in a Phase I and later, a randomized Phase II study. In the randomized study, 42 patients with recurrent/refractory disease received either: bortezomib 1·3 mg/m(2) on days 1, 4, 8 and 11 of a 3-week cycle with rituximab 375 mg/m(2) on day 1 (21 patients) or: bortezomib 1·6 mg/m(2) and rituximab on days 1, 8, 15 and 22 of a 5-week cycle (with rituximab being given only in cycles 1 and 4).Twenty-eight patients were withdrawn (toxicity 16, progression 7, and 'patient choice' 5). The main toxicities were neurological, gastro-intestinal and haematological. The overall response rate was 28/42(67%) and by histology: MCL 11/19, FL 8/15, and WM 9/10. Ten of 28 responding patients remained progression-free at 1-3·5 years. Toxicity and efficacy were equivalent between the two groups. The combination has significant toxicity but is effective, particularly in patients with WM.