Pioneering gene therapy approved for leukaemia in the US

By Mallory Locklear

A CAR-T treatment – a type of gene therapy for cancer – has been approved for use in the US. Announced by the US Food and Drug Administration (FDA) on Wednesday, this is the very first approval anywhere in the world for a type of CAR-T therapy, albeit the technologies have been used experimentally for some time.

CAR-T therapy made headlines earlier this year, when it was announced a CAR-T treatment had saved the life of Layla, a youthfull child in the UK who had leukaemia. The treatment involves reprogramming a person’s own immune cells to make them better at targeting cancerous ones.

The drug that has been approved by the FDA is Kymriah, a treatment for B-cell acute lymphoblastic leukaemia, the most common childhood cancer in the US.

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To synthesise Kymriah, a patient very first has a type of immune cell, called T-cells, eliminated from their assets and transported to a facility in Fresh Jersey operated by the pharmaceutical rock hard Novartis. Here, viruses will be used to insert a gene into these cells. The gene codes for a protein called a chimeric antigen receptor (CAR).

These cells are then reinfused back into the person. The added protein helps these modified T-cells home in on and fight leukemia cells.

In a trial, this treatment achieved an eighty three per cent remission rate over a period of three months in people who hadn’t responded to other treatment options. The FDA has approved Kymriah for people aged twenty five or under who have not responded to other treatments, or who have relapsed.

One-off treatment

Almost half the people in the trial experienced a side effect caused by an unwanted immune response triggered by the altered T-cells. Because of this, the FDA is requiring staff at the thirty two facilities approved for this treatment to fall under specific training to recognise this response, called cytokine release syndrome.

Kymriah will cost $475,000. This sounds high, but it’s lower than some analysts expected, and unlike many expensive cancer drugs, it is a one-off treatment that could result in years, not months, of extended lifespan.

The FDA’s decision has been hailed as the very first approval for a gene therapy in the US. Some argue that this isn’t a true gene therapy, as the genes introduced into the T-cells are not the treatment themselves – it is the transformed T-cells that go on to fight the cancer. But the FDA defines human gene therapy as products that introduce genetic material into a person’s DNA to treat a disease, so has classified Kymriah as such.

Europe has already approved two gene therapies for inherited diseases, while China approved a gene therapy for cancer treatment in 2004.

As for CAR-T therapies, other firms have similar treatments in the works, while Novartis also plans to get Kymriah approved for treating lymphoma.

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