Could groundbreaking CAR-T cancer therapy trigger more cancer? Premium

Car-T therapy, short for “chimeric antigen receptor T-cell”, is a cutting-edge treatment that reprogrammes a patient’s immune cells to fight their cancer.

In the last few decades, scientists have finally learned to harness the immune system to successfully treat cancer. Although doctors often use immunotherapy drugs, another type of treatment uses patient’s cells to treat their own cancers.

Car-T therapy, short for “chimeric antigen receptor T-cell”, is a cutting-edge treatment that reprogrammes a patient’s immune cells to fight their cancer. This innovative approach involves taking T-cells, a type of white blood cell that plays a crucial role in the immune system, from a patient and modifying them in a laboratory to better recognise and attack cancer cells.

These enhanced T-cells are then multiplied and infused back into the patient, where they seek out and destroy cancer cells. Lots of data shows that in difficult-to-treat lymphomas, a type of cancer, patients can do so well.

In November 2023, the US Food and Drug Administration (FDA) announced an investigation into this celebrated cancer treatment. They were looking into whether Car-T therapy might be causing new cancers in some patients who had undergone the treatment. This was a significant concern given the therapy’s reputation as a revolutionary cancer-fighting strategy.

Initially, the FDA mentioned that it had observed 20 cases where patients developed new immune-cell cancers, such as lymphomas or leukaemias, which are types of blood cell cancer, after receiving Car-T therapy. This prompted questions about who these patients were, how many such cases existed and what other treatments they might have received before Car-T therapy.

By March 2024, the FDA had documented 33 such cases among around 30,000 treated patients. Consequently, all Car-T therapies now carry a boxed warning about the potential risk of developing secondary cancers. The European Medicines Agency also started its own investigation into the matter.

Despite these concerns, it is still unclear whether the new cancers are directly caused by the Car-T cells or whether other factors are involved. It is also important to note that these cancers are very rare – as data published this month shows.