Interim pet/ct predicts outcomes of diffuse large b‐cell lymphoma (dlbcl) treated with frontline lenalidomide/rchop (r2chop): long‐term analysis of mc078e

Introduction: Evaluating prognostic impact of interim (after 2 cycles of therapy) 18F-fluorodeoxyglucose positron emission tomography-computed tomography (iPET/CT), is important for clinical trials of risk adapted therapies in treatment-naïve (TN) DLBCL. Studies evaluating iPET/CT have heterogenous methodologies and treatment regimens producing conflicting results. A prospective study of a uniformly treated and followed patients under a standardized protocol would accurately identify predictive value of iPET/CT in TN DLBCL. Here we report outcomes by iPET/CT from a phase 2 trial of lenalidomide, rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R2CHOP) in TN DLBCL (MC078E, NCT00670358). Methods: Adult patients (pts) with untreated stage II-IV DLBCL and measurable disease were enrolled. Pts with central nervous system involvement, recurrent venous thromboembolism (VTE), or inability to take 81 mg daily aspirin were excluded. Pts received 6 cycles of R2CHOP which consisted of standard doses of R-CHOP and lenalidomide 25 mg daily on days 1-10 of 21-day cycles. All pts received aspirin 81 mg for VTE prophylaxis. Pts underwent PET/CT at baseline, interim and after cycle 6. PET/CT were analyzed with 5-point Deauville Score (DS). Negative PET/CT was defined as DS of 1-3 and positive PET/CT was defined as DS of 4- 5. Primary endpoint was progression free survival (PFS) at 24 months. Secondary endpoints were overall response rates (ORR), complete response (CR) rate, event-free survival (EFS) and overall survival (OS). Results: 138 pts were accrued and 118 were eligible for MC078E. 104 pts who had iPET/CT (102 before cycle 3, 1 before cycle 2 and 1 before cycle 4) were included in this analysis. Median age was 64 (19-87) years at diagnosis. 61% were male, 86% had stage III-IV, 45% had IPI 3-5. 92 (89%) completed 6 cycles of therapy and all received at least 2 cycles. 58 had negative iPET/CT and 46 had positive iPET/CT. Overall, 103 (99%, CI95: 94.8 - 100) responded; 90 (87% (CI95: 78.4 - 92.4)) had CR. 73 (70%) were alive and progression-free at 2 years. 2-year EFS, PFS and OS were 71% (CI95 62.7-80.3), 73.9% (CI95 65.8-82.8) and 88.3% (CI95 82.4-94.8), respectively. In landmark analyses from time of iPET/CT, patients who had positive iPET/CT had significantly lower 2-year EFS (49.6%, CI95 37-66.5, p < 0.0001) and PFS (54%, CI95 41.3-70.6, p < 0.001) but not OS compared to patients with negative iPET/CT (Figure 1A,B,C). Negative iPET/CT predicted higher EFS in patients with age >60, male sex, IPI 3-5 and stage II-IV (Figure 1D). Keywords: PET-CT, Aggressive B-cell non-Hodgkin lymphoma, Combination Therapies No conflicts of interest pertinent to the abstract.