Abstract
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Objectives From our initial experience with single treatment of 131I-rituximab for patients with B-cell NHL, we observed modest response rate (29.2%) with a relatively short duration of response (median: 2.9 months). Therefore, we developed a protocol for repeated treatment with using 131I-rituximab to investigate if this protocol can increase the response.
Methods 31 patients with relapsed or refractory B-cell NHL received unlabeled rituximab 70 mg immediately prior to the administration of a therapeutic dose of 131I-rituximab, and the tumor response was evaluated 1 month later by contrast enhanced 18F-FDG PET/CT. RIT was repeated for the patients who did not progress after single treatment, and this was continued until disease progression or up to a maximum of six cycles.
Results A total of 82 cycles of RIT were administered. The repeated RIT showed twofold increases of the response rate (67.7%) and the median response duration (6.6 months), and it also induced a favorable response for patients with an aggressive histology, as compared to that of single RIT (50.0% vs. 9.1%, respectively, p=0.063). There was no significant difference in terms of response between the patients with low grade and aggressive histology (76.2% vs. 50.0%, respectively, p=0.222). The toxicities were principally hematologic, with grade 4 thrombocytopenia occurring in 12.3% and grade 4 neutropenia occurred in 16.0% of the 81 assessable treatments.
Conclusions Compared to single treatment, repeated RIT with 131I-rituximab increased the response duration and the response rate for patients with relapsed or refractory B-cell NHL, and including those patients with an aggressive histology.
Research Support Clinical Radiological Research Program of Korea Cancer Center Hospita