A novel antibody-TCR (AbTCR) T-cell therapy is safe and effective against CD19-positive relapsed/refractory B-cell...

A barrier to widespread adoption of chimeric antigen receptor (CAR) T-cell therapy is toxicity. To address this, we recently developed a novel antibody-T-cell receptor (AbTCR) platform (trademarked as ARTEMIS^®) which was designed to leverage natural immune receptor signaling and regulation. The AbTCR platform includes a gamma/delta (γδ) TCR-based AbTCR construct and a separate co-stimulatory molecule, both engineered to be tumor-specific. Here, we aim to assess the safety and preliminary efficacy of a CD19-directed AbTCR T-cell therapy.

We generated ET019003 T cells, which are autologous CD19-directed AbTCR T cells. We then conducted an early phase I study to evaluate the safety and preliminary efficacy of ET019003 T cells for the treatment of CD19-positive relapsed/refractory (r/r) B-cell lymphoma.

Sixteen patients enrolled in this study and 12 patients were treated. Of the 12 patients treated, 6 patients (50%) achieved a complete response (CR), and 4 (33%) achieved a partial response (PR) (best objective response rate [ORR] of 83%). CRs were durable, including 2 patients with ongoing CRs for 22.7 months and 23.2 months. ET019003 was well-tolerated with an attractive safety profile. No patients experienced severe (grade ≥ 3) cytokine release syndrome (CRS) and only 1 patient experienced immune effector cell-associated neurotoxicity syndrome (ICANS) of any grade. Significant elevations of cytokine levels were not seen, even in patients with marked expansion of ET019003 T cells.

This study provides initial clinical validation of the AbTCR platform as a novel cancer treatment with the potential to provide durable clinical benefit with low toxicity.

NCT03642496; Date of registration: August 22, 2018.