Englumafusp Alfa (CD19-4-1BBL) and Glofitamab Combination in Patients with Relapsed/Refractory Non-Hodgkin Lymphoma (R/R NHL): Biomarker Results from a Phase I Dose-Escalation Trial

Background:Englumafusp alfa is an antibody-like fusion protein that simultaneously targets CD19 on B cells and 4-1BB on T cells and other immune cells. In the presence of a T-cell receptor signal and strictly dependent on CD19 crosslinking, englumafusp alfa co-stimulates T cells via 4-1BB agonism that boosts T-cell effector functions and prevents T-cell anergy. An ongoing Phase I dose-escalation study (NCT04077723) is investigating the safety, efficacy, pharmacokinetics, and pharmacodynamics (PD) of intravenous administration of englumafusp alfa in combination with glofitamab in patients (pts) with R/R NHL. We recently presented preliminary clinical data demonstrating promising clinical activity and good tolerability in R/R NHL (Hutchings et al, ICML 2023). Here, we report preliminary peripheral blood (PB) and tissue biomarker analyses to demonstrate mechanisms of action (MoA), dose relationship, and baseline features associated with response.