Neoantigen T-Cell Receptor Gene Therapy in Pancreatic Cancer

Abstract

A patient with progressive metastatic pancreatic cancer was treated with a single infusion of 16.2×10⁹ autologous T cells that had been genetically engineered to clonally express two allogeneic HLA-C*08:02-restricted T-cell receptors (TCRs) targeting mutant KRAS G12D expressed by the tumors. The patient had regression of visceral metastases (overall partial response of 72% according to the Response Evaluation Criteria in Solid Tumors, version 1.1); the response was ongoing at 6 months. The engineered T cells constituted more than 2% of all the circulating peripheral-blood T cells 6 months after the cell transfer. In this patient, TCR gene therapy targeting the KRAS G12D driver mutation mediated the objective regression of metastatic pancreatic cancer. (Funded by the Providence Portland Medical Foundation.).

Figure 1. (facing page). Adoptive Immunotherapy with T-Cell Receptor (TCR)–Engineered T Cells Targeting KRAS G12D in a Patient with Pancreatic Cancer.

Panel A shows the frequency of CD4+ and CD8+ T cells (left); the transduction efficiency as measured by the detection of mouse TCRβ constant chain, which was engineered into the TCRs (middle); and the ratio of 9mer and 10mer TCR-transduced T cells (right), as determined on flow cytometry, in the patient’s infusion product. The 9mer TCR and 10mer TCR refer to two different HLA-C*08:02–restricted TCRs that specifically target 9 or 10 amino acid–long KRAS G12D neoepitopes, respectively. Panel B shows the concentrations of the effector cytokines interferon-γ and tumor necrosis factor (TNF) secreted into the supernatant after an overnight coculture of the infusion product (1×10⁵ cells per well) with autologous dendritic cells (0.5×10⁵ cells per well) pulsed with 1 μg per milliliter of the indicated wild-type or mutant KRAS G12D peptide or transfected with 80 μg per milliliter of RNA encoding wild-type or mutant KRAS G12D. I bars represent the standard error. Panel C shows the contrast-enhanced computed tomographic scans of the patient’s chest before infusion and at 85 and 176 days after the infusion of 16.2×10⁹ T cells, approximately 91.5% of which were transduced to express a KRAS G12D–reactive TCR. Arrowheads highlight lesions before and after therapy.

Figure 2.. Serum Cytokine Levels and In Vivo T-Cell Persistence.

Panels A through D show concentrations of the effector T-cell cytokines interferon-γ, TNF, granulocyte–macrophage colony-stimulating factor (GM-CSF), and CCL4 (macrophage inflammatory protein [MIP]–1β) in the serum of the patient before cell therapy on day 0 and after cell therapy up to her discharge on day 11. I bars represent the standard error. (I bars for small standard errors may not be visible.) Panel E shows the in vivo persistence of the transferred TCR-engineered T cells in the peripheral blood as determined on flow cytometric analysis of mouse TCRβ. The pie chart (Panel E, inset) shows the ratio of 9mer and 10mer TCRs within the transduced T cells at day 176 after the receipt of cell therapy (arrow). Data were gated on CD3+ lymphocytes.