GPC2-CAR T cells tuned for low antigen density mediate potent activity against neuroblastoma without toxicity

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• Pediatric cancers like neuroblastoma (NB) can express fetal antigens, such as glypican-2 (GPC2), which are silenced postnatally.
• These oncofetal antigens present potential targets for immunotherapies like CAR T-cell therapy.

Purpose of the Study:

• To develop and optimize chimeric antigen receptors (CARs) targeting glypican-2 (GPC2) for effective treatment of neuroblastoma.
• To overcome limitations of standard CAR designs in targeting tumors with clinically relevant GPC2 antigen densities.

Main Methods:

• Engineered T-cells with CARs targeting GPC2, a fetal antigen found on neuroblastoma.
• Iteratively modified CAR designs, including transmembrane and co-stimulatory domains, and overexpressed c-Jun to enhance efficacy.
• Assessed CAR T-cell efficacy and toxicity against neuroblastoma models with varying GPC2 expression levels.

Main Results:

• Standard CAR designs were ineffective against neuroblastoma with clinically relevant GPC2 site density (∼5,000 molecules/cell).
• Iterative engineering significantly lowered the GPC2-CAR antigen density threshold, enabling potent and durable eradication of neuroblastoma.
• The optimized GPC2-CAR T-cells demonstrated efficacy without observable toxicity in preclinical models.

Conclusions:

• CAR T-cell therapy targeting oncofetal antigens like GPC2 holds significant promise for treating pediatric solid tumors.
• Optimized CAR design is crucial for overcoming antigen density challenges in solid tumor immunotherapy.
• A lead GPC2-CAR candidate has been identified, demonstrating potent efficacy and safety suitable for clinical development.