Effect of short-duration chemoimmunotherapy plus radioimmunotherapy on response rates in relapsed follicular lymphoma: A U.K. NCRI Lymphoma Group Study, CR UK/07/038.

Abstract

8056 Background: Radioimmunotherapy (RIT) and rituximab (R) maintenance have been investigated after chemotherapy (CT) or R-CT in first line treatment of follicular lymphoma (FL), but less is known about the efficacy of RIT after R-CT in relapsed FL. This phase II study was conducted to examine efficacy and safety of abbreviated R-CT followed by 90Y Ibritumomab tiuxetan in patients with recurrent FL. Methods: Patients (pts) had FL, at 1st or 2nd relapse after response to R-CT or CT alone. All had WHO/ECOG performance status ≤2, and adequate bone marrow (BM), kidney, liver and cardiac function. BM involvement by lymphoma had to be <25% prior to infusion of 90Y Ibritumomab tiuxetan, but could be higher at study entry. Pts received 3 cycles of either R-CHOP or R-CVP, followed by 90Y Ibritumomab tiuxetan (15MBq/Kg, maximum 1200 MBq). No maintenance R was given. Results: 52 pts were enrolled from 6/2008 to 7/2010. Median age was 62 years (range 31-87). 46% had high FLIPI score at entry, 31% intermediate. 80% were at 1st recurrence. Median duration of best prior remission was 27.7 months. 65% pts had previously received R and 25% doxorubicin. 71% pts had R-CHOP and 29% R-CVP, prior to RIT. Overall response rate (ORR) after 3 cycles R-CT was 94% (CR/CRu 10%) and after RIT ORR 96% (CR/CRu 28%). Grade 3/4 thrombocytopenia occurred in 58% pts (median duration 16 days): 3/52 pts after R-CT and 27/52 after RIT. Grade 3/4 neutropenia occurred in 62% pts: 15/52 pts after R-CT and 27/52 after RIT. 5 pts had a total 8 grade 3 infections, only 1 attributable to RIT. 6 pts required platelets and 4 red cell transfusions. 1 pt developed myelodysplasia 10 months after 90Y Ibritumomab tiuxetan, but no other second malignancy was recorded. PFS was 31.4 months (95% CI 15.8 - not reached). There was no difference in PFS according to FLIPI score at entry or reinduction CT (R-CHOP vs R-CVP). Pts with CR/CRu following RIT showed a trend to improved PFS compared to those with PR (12 month PFS 90% versus 63%, p=0.06). Conclusions: Abbreviated R-CT and consolidation with 90Y Ibritumomab tiuxetan is an option for pts with recurrent FL, with responses of comparable duration to those seen after a full course R-CHOP.