Phase 1 study of IMCnyeso, a T cell receptor bispecific ImmTAC targeting NY-ESO-1-expressing malignancies.

IMCnyeso, an immune mobilizing monoclonal T cell receptor against cancer (ImmTAC) bispecific (New York esophageal squamous cell carcinoma [NY-ESO]×CD3) T cell engager, targets an NY-ESO-1/L-antigen family member-1 isoform A (LAGE-1A) peptide presented by histocompatibility leukocyte antigen (HLA)-A∗02:01. In this phase 1 study, 28 HLA-A∗02:01+ patients with advanced NY-ESO-1/LAGE-1A-positive advanced tumors (n = 28) receive IMCnyeso weekly intravenously (dose range: 3-300 μg; 7 dose-escalation cohorts). The primary objective is to identify the maximum tolerated dose (MTD) or recommended phase 2 dose (RP2D); additional objectives include preliminary anti-tumor activity, pharmacokinetics, immunogenicity, and pharmacodynamic changes. The study was terminated before fully enrolling dose escalation, and the MTD was not identified. There are no treatment-related discontinuations or deaths. The most common adverse events are grade 1/2 cytokine release syndrome and associated symptoms. Cytokine induction and transient lymphocyte count decreases are observed at doses 30-300 μg. At these doses, preliminary efficacy includes mixed response (2 patients) and a median overall survival of 12 months. IMCnyeso is well tolerated and, at doses ≥30 μg, induces pharmacodynamic changes consistent with T cell redirection. This study was registered at ClinicalTrials.gov (NCT03515551).