Phase I/II clinical trial of NY-ESO-1-specific TCR-engineered T-cell transfer combined with a novel T-cell stimulator CHP:NE1 for patients with refractory soft tissue sarcoma.

Abstract

TPS11074 Background: Combination therapy to enhance the efficacy of T cell receptor (TCR)-engineered T cells (TCR-T) has received increasing attention. We found that a combination therapy of TCR-T and a long peptide vaccine with CpG adjuvant without lymphodepletion regimen caused regression of immune checkpoint inhibitor-resistant sarcoma in a preclinical mouse model. Based on this finding, we initiated a clinical trial of TBI-1301 combined with CHP:NE1 without lymphodepletion for the patients with NY-ESO-1-expressing advanced soft tissue sarcoma. TBI-1301 is an NY-ESO-1157–165/HLA-A*02:01- or -A*02:06-specific TCR-T engineered to reduce endogenous TCR mRNA expression. CHP:NE1 is a novel T cell stimulator consisting of NY-ESO-1 long peptide antigen, cholesteryl pullulan (CHP) nanogel, and CpG oligoDNA. CHP nanogel is used for efficient delivery of long peptide antigen into the lymph nodes. CpG oligoDNA is a TLR9 agonist and used as an adjuvant. CHP:NE1 is expected to reinforce TBI-1301 T cells in the lymph nodes. Methods: This is an investigator-initiated multi-institutional first-in-human phase I/II clinical trial. TBI-1301 is infused at 5×109 cells one day after subcutaneous injection of CHP:NE1. CHP:NE1 is injected again 7 days after TBI-1301 infusion. This cycle is repeated once more. Lymphodepletion using cyclophosphamide and/or fludarabine is not performed. Key inclusion criteria include: refractory soft tissue sarcoma with NY-ESO-1 antigen expression, HLA-A*02:01- or HLA-A*02:06- positive, ECOG Performance Status 0 or 1, and adequate organ function. The primary objective is to assess the safety and efficacy in the phase 1 and 2 parts, respectively. The secondary objective is to assess the efficacy and immune response (blood concentration, immunophenotype and activity of TBI-1301) in the phase 1 part and the safety and immune response in the phase 2 part. Enrollment in this study is currently ongoing. Clinical trial information: JMA-IIA00346.