Deep Peripheral T Cell Immune-Profiling in Relapsed/Refractory Non-Hodgkin Lymphoma: Evaluation of Baseline Samples from the Epcoritamab Epcore NHL-1 Trial

Background: Lymphomas account for approximately 4% of cancer diagnoses worldwide, of which 90% are non-Hodgkin lymphomas (NHL). NHLs encompass a group of heterogeneous hematological malignancies with over 60 different subtypes; the most frequently diagnosed subtypes are diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). Treatment regimens incorporating α-CD20 monoclonal antibodies have become the standard-of-care for DLBCL and FL; however, intrinsic or acquired resistance will occur in the majority of patients and therefore newer therapeutic interventions are needed. Epcoritamab is a CD3 redirecting, CD20 targeting bispecific antibody that redirects patient tumor and peripheral T cells to lymphoma cells expressing CD20. Therefore understanding both the baseline T cell immune status and T cell fitness in patients with relapsed/refractory (R/R) disease is essential. Here we utilized a peripheral immune profiling multi-omics approach to enable deep characterization of the T cell immune landscape at baseline in R/R DLBCL and FL patient populations from EPCORE NHL-1, a phase 1/2, open-label, multi-center clinical trial of epcoritamab (NCT03625037; EudraCT 2017-001748-36). Methods:Samples and immune-phenotyping: Peripheral blood mononuclear cells (PBMCs) were prospectively collected from the EPCORE NHL-1 trial from patient whole blood and frozen for subsequent immune profiling. PBMCs were also collected from normal healthy volunteer (NHV) donors as age-matched controls. Multiplexed flow cytometry-based immune-phenotyping panels were developed and validated for clinical exploratory use to profile the major T cell subsets and their activation states, including CD4/CD8 naïve T cells (Tnaive), memory T cells (Tmem) and T-regulatory cells (Tregs). Eighty-seven DLBCL, 78 FL patient samples and 24 NHV controls were included in the study. Transcriptomics and TCRseq: PBMCs were also lysed for HTG EdgeSeq transcriptomic profiling and TCR repertoire sequencing (TCRseq). Normal healthy tissue gene expression was established by profiling NHV tonsils and lymph nodes as controls. FFPE DLBCL resections and core needle biopsies (n=99), FL (n=19) and normal lymph nodes (n=8) were sourced commercially. FFPE sections were processed into lysates and hybridized with HTG's Human Transcriptome Panel (HTP) probes for mRNA quantification. Results: Immune profiling of R/R DLBCL and FL patients uncovered distinct patient clusters and inter-disease specific differences in the Tnaive and Tmem cell subsets. Overall R/R FL patients showed elevated levels of CD19+ B cells at baseline compared to R/R DLBCL. DLBCL patients had increased levels of CD8+CD107a+ Tnaive /Tmem cells and PD-1+ Tregs compared to FL patients and NHV donors. In the CD4 T cell compartment, FL patients showed elevated levels of activated CD4+ T cells compared to DLBCL. Intriguingly, overall peripheral Tregs were higher in FL patients when compared to NHV donors and DLBCL patients. In good agreement with the EPCORE NHL-1 patient immune-phenotyping data in the periphery, transcriptomic profiling of commercially sourced NHL tumors showed an elevated Treg mRNA signature in FL when compared to DLBCL and NHV tonsil. Finally, the immune repertoire profiling by TCRseq in the periphery demonstrated that NHL patients generally exhibited lower clonal diversity than age-matched NHV donors. Conclusions: Comprehensive immune profiling of prospectively collected baseline PBMC samples from the EPCORE NHL-1 clinical trial using a multi-omics approach uncovered distinct inter- and intra-disease immune states in NHL patients. DLBCL patients had elevated expression of the degranulation and cytotoxic-specific marker CD107a in the periphery, suggesting an active immune state in these R/R patients. Notably, FL patients showed increased Tregs in the periphery and these data correlated with non-matched commercially sourced tumor when compared to DLBCL patients, while DLBCL patient Tregs had elevated T cell activation markers including PD-1. Finally, both DLBCL and FL patients had lower clonal diversity than NHV donors which may be a function of prior treatment. Ongoing studies include measuring the patient immune landscape over time and correlating immune pharmacodynamic/biomarkers with clinical outcomes.