Non-viral precision T cell receptor replacement for personalized cell therapy.

Area of Science:

• Immunology
• Genetics
• Oncology

Background:

• T-cell receptors (TCRs) are crucial for T-cells to identify cancer-specific mutations.
• Current T-cell therapies often face challenges in specificity and efficacy against solid tumors.

Purpose of the Study:

• To develop and evaluate a clinical-grade, non-viral CRISPR-Cas9 genome-editing approach for engineering T-cells with neoantigen-specific TCRs (neoTCRs).
• To assess the safety, feasibility, and in vivo T-cell trafficking of neoTCR-engineered T-cell products in patients with refractory solid cancers.

Main Methods:

• Simultaneous knockout of endogenous TRAC and TRBC genes using CRISPR-Cas9 non-viral genome editing.
• Insertion of neoantigen-specific TCRs (neoTCRs) into the TRAC locus, with neoTCRs isolated using personalized neoantigen-HLA capture reagents.
• Phase I clinical trial administering up to three distinct neoTCR transgenic T-cell products in a dose-escalation manner to patients with refractory solid cancers.

Main Results:

• Successful simultaneous knockout of endogenous TCR genes and knock-in of neoTCRs using a single-step, non-viral precision genome-editing method.
• neoTCR transgenic T-cells were detected in tumor biopsies post-infusion at higher frequencies than endogenous TCRs pre-infusion, indicating successful tumor trafficking.
• Observed manageable side effects, including cytokine release syndrome and encephalitis in one patient each, alongside expected chemotherapy-related side effects.

Conclusions:

• Demonstrated the feasibility of isolating and cloning multiple TCRs targeting mutational neoantigens.
• Established the clinical-grade manufacture and safety of infusing multiple gene-edited neoTCR T-cell products.
• Confirmed the ability of engineered T-cells to traffic to tumor sites in patients, supporting the potential of this approach for cancer immunotherapy.