Long-term complete responses after 131I-tositumomab therapy for relapsed or refractory indolent non-Hodgkin's lymphoma

Abstract

We present the long-term results of 18 chemotherapy relapsed indolent (N ¼ 12) or transformed (N ¼ 6) NHL patients of a phase II anti-CD20 131 I-tositumomab (Bexxar s ) therapy study. The biphasic therapy included two injections of 450 mg unlabelled antibody combined with 131 I-tositumomab once as dosimetric and once as therapeutic activity delivering 75 or 65 cGy whole-body radiation dose to patients with normal or reduced platelet counts, respectively. Two patients were not treated due to disease progression during dosimetry. The overall response rate was 81% in the 16 patients treated, including 50% CR/CRu and 31% PR. Median progression free survival of the 16 patients was 22.5 months. Median overall survival has not been reached after a median observation of 48 months. Median PFS of complete responders (CR/CRu) has not been reached and will be greater than 51 months. Short-term side effects were mainly haematological and transient. Among the relevant long-term side effects, one patient previously treated with CHOP chemotherapy died from secondary myelodysplasia. Four patients developed HAMA. In conclusion, 131 I-tositumomab RIT demonstrated durable responses especially in those patients who achieved a complete response. Six of eight CR/CRu are ongoing after 46 -70 months.

Iodine-131 Rituximab Radioimmunotherapy with BEAM Conditioning and Autologous Stem Cell Transplant Salvage Therapy for Relapsed/Refractory Aggressive Non-Hodgkin Lymphoma

“…[49][50][51][52] In contrast to the 90 Y-ibritumomab-BEAM 23 and 131 I-tositumomab-BEAM 26 protocols, our 131 I-rituximab/ BEAM protocol employs standard dose rituximab, which may confer an additional therapeutic benefit.…”

Iodine-131 Rituximab Radioimmunotherapy: Durable Control of Follicular Lymphoma

“…Rituximab is an attractive monoclonal antibody as it preferentially treats B cell lymphoma without affecting T cell function. Other advantages of 131 Irituximab RIT are the ability to repeat administration in the event of relapse, given the lack of potential for human anti-mouse antibody formation, which may occur in 131I-tositumomab radioimmunotherapy [22]. Outpatient administration of 131I-rituximab RIT is safe and the median radiation exposure is within the limits recommended by international guidelines [23].…”

Six of 12 Relapsed or Refractory Indolent Lymphoma Patients Treated 10 Years Ago with 131I-Tositumomab Remain in Complete Remission

“…The study protocol was approved by the local Ethics Committees of the University Hospitals of Lausanne and Geneva, the Intercantonal Drug Control Office (later renamed Swissmedic), and the Swiss Federal Office of Public Health, Section of Radioprotection. Eligibility criteria were as described for patients having given written informed consent (13). The most salient criteria were an indolent, CD20-positive B-cell lymphoma confirmed by histology, in relapse or resistant after at least 1 full regimen of chemotherapy.…”