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Stereotactic Adoptive Transfer of Cytotoxic Immune Cells in Murine Models of Orthotopic Human Glioblastoma Multiforme Xenografts
Published on: September 1, 2018
Clinical Evaluation of Ex Vivo Expanded MUC1-Specific Peripheral Blood T Cells for Adoptive Immunotherapy in
Erin W Meermeier1, Dara S Missan2, Latha B Pathangey1
1Department of Immunology, Mayo Clinic, Scottsdale, Arizona.
Purpose:
Naturally occurring tumor-specific T cells derived from peripheral blood (PB) offer a clinically accessible source for adoptive immunotherapy. However, the expansion of these T cells from patients with cancer remains a challenge. We hypothesized that mimicking innate immune activation could optimally stimulate antigen-driven T-cell expansion in vitro, unlocking the therapeutic potential of PB-derived T cells.
Patients And Methods:
We previously developed an ex vivo culture system that selectively expands tumor antigen-activated T cells from PB mononuclear cells (PBMC), generating multiclonal effector and central memory T cells. In this hypothesis-generating study, we evaluated the therapeutic potential of MUC1-activated T cells in patients with relapsed and/or refractory multiple myeloma (r/rMM) in a phase I clinical trial (NCT05411497). MUC1 is an oncoprotein overexpressed in r/rMM. We translated our small-scale culture into GMP-compliant, large-scale manufacturing, which achieved expansion of T cells from heavily pretreated patients' PBMCs without exhaustion. Five patients were treated with escalating doses of up to 1 × 1010 T cells.
Results:
Although the cell infusions were well tolerated, no objective responses occurred. One patient, who received the highest dose, has had stable disease for 2 years after infusion. This patient exhibited transient dermatitis with localized MUC1 and CD3 staining, as potential evidence of on-target, off-tumor T-cell reactivity, perhaps contributing to disease stabilization. T-cell receptor sequencing revealed the T-cell product in four of the patients' blood, which correlated with the product's degree of polyfunctionality and MUC1 reactivity.
Conclusions:
These findings demonstrate the feasibility, safety, and biological activity of PB-derived, MUC1-specific T cells as adoptive immunotherapy.
Significance:
Expanding tumor antigen-specific T cells for clinical use from the blood of heavily pretreated patients with cancer remains a significant hurdle. We scale up a novel culture method that integrates innate immune signals to stimulate T-cell expansion and demonstrate safety, feasibility, and a case of long-term disease stabilization upon treatment of patients with multiple myeloma in a phase I clinical trial.

