A 3-year-old with chemotherapy-resistant metastatic hepatoblastoma achieved complete regression after receiving an experimental CAR T-cell therapy. The response lasted over a year with no severe side effects reported, according to a case study in the New England Journal of Medicine. This response remained ongoing 1 year after treatment and was achieved without cytokine release syndrome (CRS) or dose-limiting toxicities, offering encouraging evidence for the potential of engineered CAR T cells in solid tumors.
This early result indicates that engineered CAR T cells may provide a new strategy for treating solid tumors. While CAR T-cell therapies have demonstrated success in blood cancers, their application in solid tumors has encountered challenges such as poor cell survival, an immunosuppressive tumor microenvironment, and difficulty reaching tumor cells. Despite these hurdles, the case highlights the potential for durable activity against solid tumors when CAR T cells are appropriately engineered.
A Challenging Cancer to Treat
Hepatoblastoma is the most common liver cancer in children. Standard treatment typically involves chemotherapy, surgery, or transplant. However, cases that spread or recur after treatment remain difficult to manage. Outcomes can be favorable for children with localized, resectable disease, but metastatic, recurrent, or chemotherapy-resistant hepatoblastoma continues to pose significant treatment challenges.
The patient in this report had a large liver tumor and lung metastases. After undergoing three rounds of chemotherapy, surgery, and metastasis removal, the cancer ceased responding and reappeared in the lungs. Before entering the CARE trial (NCT04715191), the child had received 3 lines of chemotherapy, undergone complete resection of the primary tumor, and had 2 lung metastases surgically removed.
Developing a Novel Strategy
The researchers treated the child with CAR T cells targeting glypican-3 (GPC3), a protein present on hepatoblastoma cells. These cells were modified to produce IL-15 and IL-21, which support T-cell growth and activity. GPC3 is expressed not only on hepatoblastoma cells but also on other solid tumors, making it a promising target for cellular therapy. The investigational product, referred to as CARE T cells, was manufactured from the patient’s own T cells and included an inducible caspase-9 safety switch to eliminate the cells if severe toxicity developed.
Encouraging Outcomes, Measured Enthusiasm
The child received two outpatient infusions eight weeks apart. Scans revealed partial improvement after the first dose and complete tumor disappearance after the second. This response persisted for at least a year without significant side effects. The complete response was maintained for at least 1 year, with no dose-limiting toxicities or CRS observed, showing the therapy’s safety in this case.
This case provides hope for a new treatment option, but results must be confirmed through larger studies. The trial’s extended follow-up will yield essential data on safety and durability. As reported in the New England Journal of Medicine (2026;395(10):1029-1032), this case represents a significant step forward in the development of CAR T-cell therapies for solid tumors, though further research is needed to establish broader efficacy and safety.
