CAR T-Cell Therapy Breakthrough for Solid Tumours

Why in the News?

A recent study published in the journal Science has reported a breakthrough in CAR T-cell therapy, where scientists developed a highly sensitive receptor capable of detecting faint tumour signals, potentially enabling treatment of solid cancers such as kidney and ovarian cancer.

What is CAR T-cell Therapy (Chimeric Antigen Receptor T-cell Therapy)?

• A form of immunotherapy where a patient’s T-cells are genetically modified to identify and destroy cancer cells

Existing Limitation

• Effective mainly in blood cancers like leukemia and lymphoma
• Limited success in solid tumours due to
  • Antigen Heterogeneity
    • Tumour cells vary in protein expression
    • Some cells remain undetectable to CAR T-cells

Note: An antigen is any substance—such as bacteria, viruses, toxins, or foreign proteins—that causes the immune system to produce antibodies or mount a specific defense response

Key Discovery

• Target protein: CD70
• Found in
  • 70 to 80 percent of kidney and ovarian cancers
  • Around 25 percent of pancreatic cancers
• Many tumour cells thought to lack CD70 actually contain it in very low quantities

New Innovation

HIT Receptor (HLA Independent T-cell Receptor): engineered immune receptors that enable T cells to target cancer cells without requiring HLA matching.

• Detects very low levels of tumour antigens
• Works by linking detection directly to the natural T-cell activation pathway
• Bypasses the HLA system

Results of Study

• Conventional CAR T-cells failed to eliminate all tumour cells
• HIT receptor based T-cells:
  • Eliminated hidden tumour cells
  • Achieved complete tumour removal in experimental models

Safety Concerns

• High sensitivity may attack normal cells
• Known as Goldilocks Challenge
• CD70 mostly absent in vital organs like Heart, Lungs, and Brain
• Minor effects observed in immune cells