NVG-111, a novel ROR1xCD3 bispecific antibody for non-Hodgkin lymphoma.

7549 Background: Receptor tyrosine kinase-like Orphan Receptor 1 (ROR1) is a type I transmembrane protein is highly expressed on an array of haematological and solid tumours. NVG-111 is a humanised, tandem scFv ROR1xCD3 bispecific antibody previously shown to elicit potent killing of tumour cells in vitro and in vivo by engaging a membrane-proximal epitope in the Wnt5a-binding Frizzled domain of ROR1 and redirecting T cell activity. The in vitro potency and pharmacodynamic responses to NVG-111 were assessed to support progression to a first-in-human study. Methods: The potency of NVG-111 in vitro was determined by evaluating the concentration response for cytotoxicity, T cell activation, and cytokine release in co-cultured Jeko-1 and unstimulated human T cells. Comparative data were generated for the marketed CD19xCD3 bispecific antibody, blinatumomab. Potency data for NVG-111 were used together with allometric scaling from murine PK studies to inform planned clinical doses. Results: NVG-111 demonstrated T cell-dependent cytotoxicity, T cell activation and levels of cytokine release similar in potency to blinatumomab. Cytotoxic responses of both NVG-111 and blinatumomab were more potent than T cell activation and cytokine release. Dose response curves for NVG-111 showed a decrease in activity beyond the concentration of maximal response (ie “hook effect”). We hypothesise this is due to receptor saturation, inhibiting synapse formation. NVG-111 has progressed to a Phase 1/2 first-in-human study in patients with debulked, relapsed/refractory chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), the drug given as add-on to ≥2nd line therapy with a Bruton’s tyrosine kinase inhibitor, or venetoclax. Phase 1 includes escalating doses of 0.3 to 360 µg/day via continuous infusion over 3 cycles (each 21 days on, 7 days off) to establish safety, PK, pharmacodynamics (PD) and recommended phase 2 dose (RP2D). Predicted exposure at 0.3 µg/day is ̃EC20 for cytotoxicity in vitro and below the lowest EC10 for cytokine release. PD biomarkers in the study include systemic cytokines. Phase 2 will study efficacy and safety of the RP2D in CLL and MCL, with primary endpoint complete response rate; other efficacy endpoints include minimal residual disease and progression free survival. Conclusions: NVG-111 shows potent T-cell mediated lymphoma cell cytotoxicity in vitro at concentrations well below those associated with extensive cytokine release. NVG-111 is in an ongoing Phase 1/2 study and may present a novel option for adoptive immunotherapy in patients with non-Hodgkin lymphoma and potentially other cancers. Clinical trial information: 2020-000820-20. [Table: see text]