Durable complete responses from therapy with combined epratuzumab and rituximab

BACKGROUND. In this international, multicenter trial, the authors evaluated rituximab (anti‐CD20) plus epratuzumab (anti‐CD22) in patients with postchemotherapy relapsed/refractory, indolent non‐Hodgkin lymphoma (NHL), including long‐term efficacy. METHODS. Forty‐nine patients with follicular NHL (FL) (N = 41) or small lymphocytic lymphoma (SLL) (N = 7) received intravenous epratuzumab 360 mg/m2 and then intravenous rituximab 375 mg/m2 weekly ×4. The regimen was tolerated well. RESULTS. Twenty‐two of 41 patients with FL (54%) had an objective response (OR), including 10 (24%) complete responses (CR) (CR/unconfirmed CR [CRu]), whereas 4 of 7 patients with SLL (57%) had ORs, including 3 (43%) with CR/CRu. Rituximab‐naive patients (N = 34) had an OR rate of 50% (26% CR/CRu rate), whereas patients who previously responded to rituximab (N = 14) had an OR rate of 64% (29% CR/CRu rate). An OR rate of 85% was observed in patients with FL who had Follicular Lymphoma International Prognostic Index (FLIPI) risk scores of 0 or 1 (N = 13), whereas 28 patients with intermediate or high‐risk FLIPI scores (≥2) had an OR rate of 39% (18% CR/CRu rate). In patients with FL, the median response duration was 13.4 months, and that duration increased to 29.1 months for 10 patients who had a CR/CRu, including 4 patients who had durable responses with remissions that continued for >4 years. In patients with SLL, the median response duration was 20 months, including 1 patient who had a response that continued for >3 years. CONCLUSIONS. The combination of epratuzumab and rituximab induced durable responses in patients with recurrent, indolent NHL. Cancer 2008. © 2008 American Cancer Society. In this international, multicenter trial, combined rituximab (anti‐CD20) and epratuzumab (humanized anti‐CD22 antibody) induced durable responses in patients with recurrent, indolent non‐Hodgkin lymphoma.