High-dose chemo-radioimmunotherapy with autologous stem cell support for relapsed mantle cell lymphoma

Relapsed mantle cell lymphoma is a radiation-sensitive malignancy that Is unlikely to be cured by treatment with conventional high-dose therapy and autologous stem cell transplantation. We tested the safety and efficacy of using a CD20-specific monoclonal antibody conjugated with I-131 to deliver high-dose radiation selectively to all lymphoma sites. Patients with relapsed or refractory mantle cell lymphoma received Infusions of I-131-labeled CD20-specific monoclonal antibody (Tositumomab). The antibody dose was 1.7 mg/kg body weight, and the amount of I-131 was calibrated to deliver 20 to 25 Gy to vital normal organs. This treatment was followed 10 days later by administration of high-dose etoposide (30-60 mg/kg), cyclophosphamide (60100 mg/kg), and Infusion of cryopreserved autologous stem cells. The 16 patients In this study had received a median of 3 prior treatments, and 7 had chemotherapy-resistant disease. The median dose of I-131 was 510 mCi (18.87 GBq). There were no therapy-related deaths. Among the 11 patients with conventionally measurable disease at the time of treatment, the respective complete and overall response rates were 91% and 100%. Fifteen patients remain alive, and 12 have had no progression of lymphoma at 6 to 57 months from transplantation and 16 to 97 months from diagnosis. Overall survival at 3 years from transplantation Is estimated at 93%, and progression-free survival is estimated at 61%. High-dose treatment with I-131-Tositumomab, etoposide, and cyclophosphamide results In a high remission rate and may provide long-term disease-free survival for patients with relapsed or refractory mantle cell lymphoma. (C) 2002 by The American Society of Hematology.