Phase II trial of the combination of denileukin diftitox and rituximab for relapsed/refractory B-cell non-Hodgkin lymphoma.

Denileukin diftitox plus rituximab was evaluated in relapsed/refractory B-cell non-Hodgkin lymphoma patients. Of the 38 evaluable patients, 30 (80%) were rituximab-refractory. The overall response rate (ORR) was 32%, with six complete responses (CR) and six partial responses (PR). The median time to progression for responders was 8 months (range: 2-36+); two patients with rituximab-refractory follicular lymphoma were in CR at 25 and 36+ months. The ORR was 55% (4 CRs, 2 PRs) in 11/14 patients with rituximab-refractory follicular lymphoma, and 100% in the three patients with rituximab-sensitive tumour. Most toxicities were low grade and transient, and myelotoxicity was uncommon.