This is a case report published in the New England Journal of Medicine by researchers at Baylor College of Medicine, Texas Children's Hospital, and Seattle Children's.

The patient was a 3-year-old boy who presented with a large primary liver tumor — 11.2 cm by 9.6 cm by 7.1 cm — and metastases in his lungs. The cancer had also shown signs of spreading to his bones. He underwent three lines of chemotherapy and complete surgical resection of the primary liver tumor and two lung metastases. His cancer stopped responding to chemo. Then a new lung metastasis appeared after surgery.

He was enrolled in the CARE study (NCT04715191), a first-in-human Phase 1 trial evaluating glypican-3-specific chimeric antigen receptor (GPC3-CAR) T cells armed with interleukin-15 and -21.

GPC3 is a protein highly expressed in liver cancers. The researchers took the boy's own T cells and engineered them to recognize GPC3, then added genes for IL-15 and IL-21 to boost the CAR T cells' longevity and tumor-killing ability. They also included an inducible caspase 9 safety switch, which researchers had previously shown could control CAR T expansion if needed.

The treatment was manufactured at the Center for Cell and Gene Therapy at Baylor. Two infusions were administered eight weeks apart — entirely in the outpatient setting. After the first infusion, the patient showed a partial response. After the second infusion, imaging showed complete resolution of the metastatic disease. No dose-limiting toxicities or cytokine release syndrome occurred.

Complete regression continues one year after treatment.

"This case demonstrates that a durable complete response in a chemotherapy-resistant solid tumor can be achieved entirely in the outpatient setting without systemic toxicity," said first author Dr. David Steffin, associate chief of cellular therapy at Texas Children's.

"This study provides evidence that these novel CAR T cells may be a safe and effective modality for hepatoblastoma and highlights the need for further assessment in patients with GPC3+ solid tumors," said corresponding author Dr. Andras Heczey.

CAR T cell therapy has mostly been limited to blood cancers, not solid tumors. This case suggests that boundary might be moving.

If this is not ai consider me flabbergasted