Moving Radioimmunotherapy Forward for Follicular Lymphoma

Abstract

The treatment of follicular non-Hodgkin lymphoma (NHL), which is the second most common NHL in Western countries, continues to evolve. In this issue of Journal of Clinical Oncology, two important reports deal with the upfront use of radioimmunotherapy (RIT) in follicular lymphoma (FL). Both of these studies enrolled FL patients who were considered to be in need of therapy. The report by Scholz et al 1 used RIT as a single-agent without any chemotherapy, whereas the second study by Press et al 2 was a phase III randomized trial of the standard six cycles of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) versus six cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) with RIT as consolidation (Southwest Oncology Group [SWOG] S0016). The results of these studies have implications for current care and the design of future studies but, as is typical for FL studies, leave us with nagging unanswered questions. RIT is a unique therapeutic modality that uses an antibody carrier to target high-energy, short–path-length radionuclides to tumor sites with little effect on other solid organs. If pretherapy guidelines are followed, the only toxicity is reversible myelosuppression. The known sensitivity of FL to conventional radiation therapy and the usual widespread nature of FL make this type of NHL an attractive target for RIT. Indeed, early randomized studies of unlabeled antibody versus the radiolabeled version of essentially the same antibody in relapsed indolent NHL demonstrated the advantage of the radioimmunoconjugate (RIC) with respect to the overall response rate (ORR) and complete response (CR) rates. 3,4