Tandem HD-chemotherapy and myeloablative radioimmunotherapy with 131I-anti-CD20 rituximab in relapsed and refractory B-cell lymphoma: Results of a phase II study of the German RAIT Study Group

Abstract

13007 Background: Radioimmunotherapy has been shown to be effective in CD20 + B-cell lymphomas. Both non-myeloablative as well as myeloablative regimens have been employed for low grade and high grade lymphomas with impressive response rates and remission durations. Recently, the Press group and our group published data on myeloablative 131-I-anti-CD20 RAIT with high response rates and favourable long term survival especially in follicular lymphomas and transformed FL. Therefore, a phase II study is currently being done within the German Radioimmunotherapy Group, interim analysis data are presented. Methods: Patients were to receive R-Dexa-BEAM, followed by BEAM and HD-RAIT 2–6 months after BEAM. 131-I-Rituximab was administered with a maximum kidney and lung dose of 25 Gy. Sample size was calculated to be 16 to evaluate toxicity and feasibility of the tandem approach as primary endpoint. Results: 16 pts with relapsed (14) or primary refractory (2) B-cell lymphomas (FLI,II: 4pts; DLBCL: 4pts (all early relapses); transformed FL: 6 pts; MCL:1 pt, marginal zone lymphoma: 1 pt) were treated with 1 (15 pts) or 2 cycles (1 pt) of R-Dexa-BEAM. 13/16 pts achieving PR (5) or CRu (8) were treated with BEAM, 2 pts with PD and 1 with subdural hematoma were drop outs. After BEAM, 9/13 pts were in CR, 3/13 PR, 1/13 PD. Of 12 responding pts, 6 received HD-RAIT (1 pancytopenia, 1 hepatic, 2 pulmonary toxicity, 3 too early). After HD RAIT, 5/6 pts were in CR, 1 in PR. 4/6 pts (3 CR, 1 PR) are alive for 22–31 months, 2 pts died in CR, 1 of interstitial lung disease 2 months after HD-RAIT, 1 pt of pneumonia 8 months after HD-RAIT. Conclusions: Myeloablative RAIT is a feasible and effective treatment modality for relapsed poor prognosis CD20+ B-NHL not having severe toxicity due to the salvage regimen and HD-chemotherapy. HD RAIT offers the potential for long term relapse free survival. Final analysis of toxicity and outcome of this phase II study will be presented at the meeting. No significant financial relationships to disclose.