Radioimmunotherapy of B-cell non-Hodgkin's lymphoma: from clinical trials to clinical practice.

Radioimmunotherapy (RIT) is a new treatment modality for B-cell non-Hodgkin's lymphoma (NHL). Recent clinical trials have clearly established its efficacy in NHL patients refractory to standard chemotherapy or immunotherapy with the widely used unconjugated rituximab monoclonal antibody (mAb). The Food and Drug Administration has approved (90)Y-ibritumomab tiuxetan anti-B-cell NHL mAb as the first commercially available radiolabeled antibody for cancer therapy. This comes only a few years after the introduction of rituximab into clinical practice as the first unconjugated antibody for cancer treatment, underscoring the success of both immunotherapy and RIT in the treatment of NHL. With the approval of (90)Y-ibritumomab tiuxetan, and based on the results of numerous clinical trials with radiolabeled anti-B-cell NHL mAbs, RIT promises to become integral to nuclear medicine practice. In this article, the basic concepts of RIT are reviewed with important milestones in its development for B-cell NHL treatment and particular emphasis on phase II and III clinical trials establishing its efficacy in clearly defined patient populations. Finally, the prospects for the expected widespread clinical use of RIT in the management of B-cell NHL, alone or in combination with other more established therapies, are discussed. This article provides both investigative and clinical nuclear medicine physicians with a better understanding of RIT capabilities and limitations in B-cell NHL and their role as consultants in the care of NHL patients.