A phase II study of bortezomib in patients with MALT lymphoma.

We have performed a phase II study to evaluate bortezomib in patients with MALT-lymphoma. Sixteen patients entered the trial, 4 had gastric MALT-lymphoma, 7 of the ocular adnexa, one of the colon, and 2 of the parotid, and one patient each the lung and the breast. Bortezomib was given at 1.5 mg/m(2) days 1, 4, 8 and 11; repeated every 21 days. The overall response rate was 80% (13/16); 7 patients achieved complete remission (43%), 6 partial response (37%) and 3 stable disease. After a median follow-up of 23 months (range; 8-26), all patients are alive and 4 have relapsed. Fifteen patients required dose reductions due to either neuropathy (7 patients) or diarrhea (8 patients). Bortezomib appears to be active in patients with MALT-lymphoma. However, an unexpectedly high rate of toxicities was seen, warranting assessment of combination schedules with bortezomib at a lower dose than given in our study.