Radioimmunotherapy (RIT) for Follicular Lymphoma achieves long term lymphoma control in first line and at relapse: 8‐year follow‐up data of 281 patients from the international RIT‐registry

Abstract

Summary To assess efficacy of radioimmunotherapy (RIT) in follicular lymphoma, data from 281 patients collected in the RIT Network, with a median follow‐up of 8·2 years after RIT were analysed. RIT was given at first line in 18·5% and at relapse in 81·5%. Following first line therapy, 76·9% achieved complete remission (CR), 9·6% partial remission (PR), 1·9% stable disease (SD) and 1·9% had progressive disease (PD); response was not documented in 9·7%. At relapse, the rate of CR was 48·5% and that of PR was 16·6%, SD 2·6% and PD 10·5%; response was not documented in 21·8%. After median follow‐up of 8·2 years, median progression‐free survival (PFS) for all was 2·54 years, median overall survival (OS) was not reached. Median PFS and OS (both not reached) were significantly better in first line, compared to RIT at relapse (PFS, 2·11 years; OS, 10·8 years; P = 0·0037 and P = 0·0021, respectively). Overall 8‐year PFS was 33·9%, 53·6% for first line and 29·6% for relapsed individuals. Overall 8‐year OS was 58·8%, 78·1% for first line and 54·5% for relapsed patients. Thirty‐five patients (12·5%) developed secondary malignancy and 16 patients (5·7%) experienced transformation into aggressive lymphoma. RIT is a safe and effective treatment option for follicular lymphoma, both at front line and relapse with an 8‐year PFS of 53·6% and 29·6%, respectively.

Radioimmunotherapy with 131I‐rituximab for patients with relapsed or refractory follicular or mantle cell lymphoma

“…During the follow‐up period, secondary malignancy was also reported in 3 of 24 patients (12.5%). In other large RIT registry studies of follicular lymphoma or mantle cell lymphoma that have been followed for a long time, secondary malignancy was reported similarly at 12.4% and 12%, respectively 21–22 The secondary malignancy frequencies reported in both studies were comparable to those in our study. Additional investigation is needed on the prevalence and prognosis of secondary malignancies through long‐term follow‐up RIT studies.…”

90Y-ibritumomab Tiuxetan in B-cell Non-Hodgkin Lymphomas: Real-world Data From the United Arab Emirates

“…In the report of the RIT Network (285 FL cases), secondary neoplasms developed in 12.5% (22 solid and 13 hematologic neoplasms, most commonly acute myeloid leukemia and myelodysplastic syndrome), and histologic transformation occurred in 5.7% of cases with a median follow-up of 8.2 years. 27 In our study, the treatment's short-term safety profile was similar to that reported earlier, with 13.0% of cases developing grade 3 or 4 hematologic toxicity of which none urged therapy cessation. Although we had 1 case of acute myeloid leukemia, the follow-up length did not allow us to draw firm conclusions about long-term safety (carcinogenic effects of radiation may manifest 5-10 years later than exposure).…”

“…Of note, we did not use the treatment in bulky cases (per the drug's label), and most patients refused external beam radiation therapy. Besides, the proportion of patients receiving 90 YIT in first line (33%) was higher than that observed in the literature (19%), 27 which is probably the consequence of our unique setting (easy-toaccess RIT vs difficult-to-access ASCT; Fig. 1).…”

“…26 According to recent, long-term, follow-up data from the international RIT Network, patients receiving 90 YIT in first line had a higher 8-year OS and progression-free survival (PFS) compared with those treated with the drug after relapse (78.1 vs 54.5% and 53.6 vs 29.6%, respectively). 27 In refractory or relapsing FL cases, 90 YIT proved to be effective in the long term (≥5 years of follow-up; mean estimated OS, 82.3 months) with an acceptable healthrelated quality of life. 28 In our study, the length of follow-up was a median 3 years for the 90 YIT group (median OS and EFS were not reached), but no FL cases treated with 90 YIT relapsed during follow-up.…”

Radioimmunotherapy for Mantle Cell Lymphoma: 5-Year Follow-up of 90 Patients from the International RIT-Registry

“…The registry is maintained by a professional clinical research organization (CRO; Alcedis GmbH, Giessen, Germany). Further information regarding the EDC system has been published recently [7]. For the analysis presented here, all initially participating centres with documented mantle cell lymphoma (MCL) patients in the RIT-NT were contacted via mail to take part in the extended follow-up for MCL.…”