A phase I/II trial of WT1-specific TCR gene therapy for patients with acute myeloid leukemia and active disease post-allogeneic hematopoietic cell transplantation: skewing towards NK-like phenotype impairs T cell function and persistence
Francesco Mazziotta, L. Martin, Daniel Egan, Merav Bar, Sinéad Kinsella, Kelly G. Paulson, Valentin Voillet, Miranda C. Lahman, Daniel Hunter, Thomas M. Schmitt, Natalie Duerkopp, Cecilia C.S. Yeung, Tzu-Hao Tang, Raphaël Gottardo, Yuta Asano, Elise C. Wilcox, Bo Lee, Tianzi Zhang, Paolo Lopedote, Livius Penter, Catherine J. Wu, Filippo Milano, Philip D. Greenberg, Aude G. Chapuis
Abstract
Abstract Relapsed and/or refractory acute myeloid leukemia (AML) post-allogeneic hematopoietic cell transplantation (HCT) is usually fatal. We previously reported that post-HCT immunotherapy with Epstein-Barr virus (EBV)-specific donor CD8 + T cells engineered to express a Wilms Tumor Antigen 1-specific T-cell receptor (T TCR-C4 ) appeared to prevent relapse in high-risk patients. In this phase I/II clinical trial (NCT01640301), we evaluated safety (primary endpoint), persistence and efficacy (secondary endpoints) of EBV- or Cytomegalovirus (CMV)-specific T TCR-C4 in fifteen patients with active AML post-HCT. Infusions were well tolerated, with no dose-limiting toxicities or serious adverse events related to the product. However, T TCR-C4 cells did not clearly improve outcomes despite EBV-specific T TCR-C4 cells showing enhanced potential for prolonged persistence compared to CMV-specific T TCR-C4 . Investigating the fate of persisting T TCR-C4 , we identified a shift towards natural killer-like (NKL) terminal differentiation, distinct from solid tumor-associated canonical exhaustion programs. In one patient, treatment with azacitidine appeared to mitigate this NKL skewing, promoting T TCR-C4 persistence. These findings suggest that AML drives a distinct form of T-cell dysfunction, highlight the need for targeted approaches that preserve T-cell fitness, ultimately improving the efficacy of cellular therapies for AML.