Recurrent Hodgkin's Disease (HD) provides unique opportunities to improve radiolabeled immunoglobulin therapy (RIT). Normal tissue toxicity after RIT is limited to bone marrow damage and is well documented and quantified in HD patients. Anti-antibody formation is rare in patients with HD, allowing for multiple RIT cycles. Overall, 134 patients with recurrent HD were treated on five different studies with i.v. antiferritin, labeled with 131I or with 111In for diagnostic purposes and 90Y for therapeutic purposes.
Patients with recurrent, end-stage HD obtain a 60% response rate following 90Y-labeled antiferritin. One-half of the therapy responses are complete. Responses are more common in patients with longer disease histories (>3 years) and smaller tumor volumes (<30 cm3) and in patients receiving at least 0.4 mCi 90Y-labeled antiferritin/kg body weight. Complete responders survive significantly longer than partial responders (2 years versus 1 year). Partial responders survive longer than patients with progressive disease (1 year versus 4 months). HD in one-third of the patients recurs in new areas. A low protein dose (2–5 mg) and a moderate specific activity (10 mCi/mg) are recommended. Results obtained with 90Y-labeled antiferritin are significantly better than results with 131I-labeled antiferritin.
Further translational research in vitro in the radiopharmacy and in vivo with experimental animals is ongoing to improve the therapeutic results of RIT in HD. Obviously, many permutations of RIT cannot be explored in HD patients for ethical, financial, or logistic reasons, and predictive preclinical research is required to achieve further progress. Currently, RIT is a low-toxicity, low-cost outpatient procedure for recurrent HD with a high response rate in a patient population with an unfavorable prognosis.
Presented at the “Fifth Conference on Radioimmunodetection and Radioimmunotherapy of Cancer,” October 6–8, 1994, Princeton, NJ. This study was supported in part by Grants CA43791 and CA51161 from the National Cancer Institute, United States Department of Health and Human Services, Bethesda, MD.