FOLLOW-UP OF RELAPSED B-CELL LYMPHOMA PATIENTS TREATED WITH IODINE-131-LABELED ANTI-CD20 ANTIBODY AND AUTOLOGOUS STEM-CELL RESCUE

Purpose: Radioimmunotherapy (RIT) is a promising treatment approach fo r B-cell lymphomas, This is our first opportunity to report long-term follow-vp data and late toxicities in 29 patients treated with myeloab lative doses of iodine-131-anti-CD20 antibody (anti-B1) and autologous stem-cell rescue, Patients and Methods: Trace-labeled biodistribution studies first determined the ability to deliver higher absorbed radia tion doses to tumor sites than to lung, liver, or kidney at varying am ounts of anti-B1 protein (0.35, 1.7, or 7 mg/kg), Twenty-nine patients received therapeutic infusions of single-agent I-131-anti-B1, given a t the protein dose found optimal in the biodistribution study labeled with amounts of I-131 (280 to 785 mCi [10.4 to 29.0 GBq]) calculated t o deliver specific absorbed radiation doses to the normal organs, foll owed by autologous stem-cell support. Results: Major responses occurre d in 25 patients (86%), with 23 complete responses (CRs; 79%), The non hematopoietic dose-limiting toxicity was reversible cardiopulmonary in sufficiency, which occurred in two patients at RIT doses that delivere d greater than or equal to 27 Gy to the lungs. With a median follow-up time of 42 months, the estimated overall and progression free surviva l rates are 68% and 42%, respectively, Currently, 14 of 29 patients re main in unmaintained remissions that range from 27+ to 87+ months afte r RIT, Late toxicities have been uncommon except for elevated thyroid- stimulating hormone (TSH) levels found in approximately 60% of the sub jects, Two patients developed second malignancies, but none have devel oped myelodysplasia (MDS), Conclusion: Myeloablative I-131-anti-BT RIT is relatively well tolerated when given with autologous stem-cell sup port and often results in prolonged remission durations with few late toxicities. (C) 1998 by American Society of Clinical Oncology.