Dose-Adjusted EPOCH and Rituximab (DA-EPOCH-R) Treatment in Dual Expressor Diffuse Large B-Cell and Double/Triple Hit Lymphomas: TP53 Mutations Influence on Clinical Outcome

Introduction: Diffuse Large B-Cell Lymphoma (DLBCL) is an heterogeneous disease: 30-40% of cases have high expression of MYC and BCL2 proteins (Dual Expressor, DE) and 5-10% have chromosomal rearrangements involving MYC, BCL2 and/or BCL6 (Double-/ Triple-Hit, DH/TH). Although the optimal treatment for those high-risk lymphomas remains undefined, DA-EPOCH-R produces durable remission with acceptable toxicity (Dunleauvy K, Lancet 2018). TP53 mutation is an independent marker of poor prognosis in patients (pts) with DLBCL treated with R-CHOP therapy. However, its prognostic value in poor prognosis lymphomas, receiving intensive therapy, has not been investigated yet. Methods: A series of consecutive pts (n=87) with biopsy proven diagnosis of DE DLBCL (MYC expression ≥40% and BCL2 expression ≥ 50% of tumor cells) or DE-Single Hit (DE-SH, i.e., DE-DLBCL with a single rearrangement of either MYC, BCL2 or BCL6 oncogenes) or DE-DH/TH (MYC, BCL2 and/or BCL6 rearrangements obtained by FISH) were treated with 6 cycles of DA-EPOCH-R and central nervous system (CNS) prophylaxis consisting of two courses of high-dose intravenous Methotrexate. Additional eligibility criteria included age ≥18 years and adequate organ functions. Cell of origin (COO) was defined according to Hans algorithm [germinal center B cell like (GCB) and non GCB)]. TP3 mutations were evaluated by next generation sequencing (NGS) based on AmpliseqTM technology or Sanger sequencing and considered positive when a variant allelic frequency ≥10% was detected. Results: Eighty-seven pts were included [n=36 DE only, n=32 DE-SH (n=8 MYC, n=10 BCL2, n=14 BCL6), n=19 DE-DH/TH] with 40 patients (46%) showing a non GCB COO. Pts had a median age of 59 years (range, 24-79 years). Seventy-three pts (84%) had advanced disease and 44 (50%) an high-intermediate/high-risk score as defined by International Prognostic Index (IPI). Only 8 of 87 pts (9%) were consolidated in first clinical remission with autologous stem cell transplantation following DA-EPOCH-R. After a median follow-up of 24 months, 73 are alive (84%) and 14 died [n=12 disease (n=2 CNS disease); n=1 pneumonia; n=1 suicide]. The 2-year PFS and OS were 71% (95%CI, 60-80%) and 76% (95%CI, 61%-85%) for the entire population. For those with IPI 3-5 the PFS and OS were not significant different for DE and DE-SH pts versus DE-DH/TH pts [64% vs 57% p=0.77); 78% vs 57% p=0.12)]. The COO did not influence the outcome for DE only and DE-SH [PFS: 78% vs 71% (p=0.71); 92% vs 86% (p=0.16) for GCB vs non -GCB, respectively]. Fourty-six pts (53%;n=18 DE only, n=18 DE-SH, n=10 DE-DH/TH ) were evaluated for TP53 mutations with 11 pts (24%) carrying a clonal mutation (n=6 in DE, n=3 in DE-SH, n=2 in DE-DH/TH). The 2-year PFS and OS did not significantly change for pts DE and DE-SH TP53 wild type as compared to DE and DE-SH mutated [PFS: 84 % vs 77%, (p=0.45); OS: 87% vs 88%, (p=0.92)]. The two pts DE-DH/TH with TP53 mutation are alive and in complete remission.Conclusions: High risk DLBCL pts treated with DA-EPOCH-R have a favourable outcome independently from high IPI score, DE-SH and DE-DH/TH. Also the presence of TP53 mutations does not negatively affect the outcome of pts treated with this intensive regimen. The efficacy of DA-EPOCH-R in overcoming poor prognostic genetic features in DLBCL should be confirmed in a larger prospective clinical trial.