Centralized radiolabeling of antibodies for radioimmunotherapy

The purpose of this article is to discuss the factors involved in the selection of antibodies, radionuclides and labeling methods in the development of radioimmunotherapy (RIT) for non-Hodgkin's lymphoma (NHL) from a single clinical study site through multicenter trials and commercialization.

The development of an effective radioimmunotherapeutic agent is described, with a discussion of the practical considerations in its development. The critical issues related to the commercial preparation and administration of 1311 anti-B1 for therapeutic purposes are reviewed.

RIT with radiolabeled antibodies to the CD20 surface antigen represents a new modality for the treatment of NHL and, potentially, other malignancies. One monoclonal antibody showing great promise for the treatment of NHL is 131I-labeled anti-B1. Iodine-131 is preferred by many investigators over other radionuclides such as 90Y for labeling therapeutic antibodies because of its relatively low cost, accessibility, ease of labeling, 8-day half-life and imaging capabilities. To ensure their safety and consistency, radiolabeled antibodies must undergo the same quality assurance measures as nonradioactive pharmaceuticals. Therefore, radiolabeling in a centralized facility has numerous advantages over localized radiolabeling in the preparation of 131I-labeled antibodies for RIT.

Centralized radiolabeling has significant advantages over the local production of radiolabeled antibodies. The developmental challenges of centralized radiolabeling have been successfully addressed for 131I anti-B1 therapy.