LONG‐TERM FOLLOW‐UP AND GENE EXPRESSION PROFILES ASSOCIATED WITH OUTCOME IN PATIENTS WITH RELAPSED AGGRESSIVE B‐ OR T‐CELL LYMPHOMAS TREATED IN THE NORDIC P[R]EBEN TRIAL

Abstract

Introduction: The Nordic Lymphoma Group (NLG) performed a dose-finding/expansion trial evaluating pixantrone, etoposide, bendamustine and, in CD20+ lymphomas, rituximab (P[R]EBEN) in patients (pts) with relapsed diffuse large B-cell (DLBCL) or peripheral T-cell (PTCL) lymphomas. The regimen was out-patient based, and applicable in frail, heavily pre-treated pts. Here we present a long-term follow-up of the trial and a per-protocol correlative biological analysis of pre-therapeutic tumour biopsies looking for gene expression profiles associated with long-term response. Methods: We enrolled 60 pts (37 DLBCL and 23 PTCL; age range: 39–84 yrs, median: 71 yrs). Time to event parameters were analyzed by Kaplan-Meier estimates, log-rank test and Cox regression models. Pre-therapeutic biopsies from 42 pts (25 DLBCL, 17 PTCL) were analyzed for gene expression by NanoString PanCancer Pathways and Immune profiling panels (altogether 1348 genes). Results: Of the original 60 patients, 22 were alive at the time of the present analysis. The median follow-up of surviving pts was 41 mo (range 26–76 mo). The 38 deaths were due to: lymphoma (24; 63%), infections (3; 8%) and other causes (11; 29%: 1 lung carcinoma, 5 acute myeloid leukemia-AML, 1 myelodysplasia-MDS, 1 lung embolism, 1 allotransplant related and 2 unknown). Of the 6 pts with AML/MDS, 5 were PTCL and 1 DLBCL. Of 58 evaluable pts, 38 (65%) had a complete (CR) and 1 (3%) a partial response (B: 51%; T: 70%). The median duration of response (DoR) of the 38 CR pts was 17 mo (range 0.5–55 mo; B: 18 mo; T: 17 mo). Four pts were bridged to allogeneic transplant. The overall 5-yr OS and PFS were 33% and 19%, respectively. The median OS for DLBCL was 16.0 mo [IQR 7.0>] and for PTCL 18.0 mo [IQR 8.0>]. The median PFS for DLBCL was 10.0 mo [IQR 4.0–32.0] and for PTCL 10.0 mo [IQR 5.0–26.0]. To better understand molecular alterations underlying the delay of relapse in this heavily pre-treated elderly population, we determined differentially expressed genes between short (<12 mo) and long term (>12 mo) responders. In DLBCL, 31 genes showed significant differential expression between short- and long-term responders (P < 0.05). The latter had higher expression of genes related to transcription factor activity. The gene most significantly associated with long-term response was Neutrophil Cytosolic Factor 4 (NCF4). In PTCL, 23 genes were differentially expressed between short- and long-term responders, the latter showing enrichment in Ras signaling pathway genes (e.g., Rac Family Small GTPase 3, RAC3, and phospholipase A2 group IIA, PLA2G2A). The research was funded by: Servier Laboratoires Keywords: Aggressive B-cell non-Hodgkin lymphoma, Aggressive T-cell non-Hodgkin lymphoma, Combination Therapies No conflicts of interests pertinent to the abstract.