CAR T therapy provides long-term ‘cures’ for two leukaemia patients

Interview with Talk of the Town on Dundalk FM 16/02/22

A new therapy for cancer, which uses patients’ own cells to fight the disease, and has been available in Ireland since December last, has cured two patients of chronic lymphocytic leukaemia who were among the first to receive CAR T therapy in 2010.

There are no signs of cancer in the two, now healthy, patients according to the results of research into the long term effects of CAR T therapy undertaken at the University of Pennslyvania and reported earlier this month in the science journal Nature.

“This is remarkable since the cancers are resistant to conventional treatment,” says Professor Martin Pule, Director of the University College London Cancer Institute CAR T-cell programme in the UK. “This, and the growing body of clinical study data, gives us a lot of hope that we can indeed start cautiously talking about some patients being cured of their cancers following CAR T cell therapy,” says Pule.

CAR T therapy works through harnessing the disease-fighting ability of T cells, which are part of the immune system, says Professor Karen English, a researcher in the faculty of science and engineering at Maynooth University working in cell therapy, a field that includes CAR T research.

A sample of the patient’s blood is taken and T cells are separated out, says English. “This cell is chosen because it has the power to kill cancer cells. The T cells are then ‘supercharged’ in the laboratory so that they can recognise the cancer cells. “

The supercharged T cells are then put back into the cancer patient through an intervenous injection, says English, after which the T cells seek out the cancer cells in the blood and kill them. “This approach genetically engineers the T cells with a ‘homing beacon’ so that they immediately recognise the cancer cells and kill them.”

In the UK, CAR T therapy has been available to patients since December 2018, up until the therapy became available in Ireland at St James’s Hospital and Our Lady’s Children’s Hospital Crumlin last December, patients in Ireland were sent to the UK.

The treatment has about a 40% success rate, in people that otherwise are facing terminal illness, says Professor Larry Bacon, Consultant Haemolotologist and clinical lead for the National Adult CAR-T Centre at St James’s Hospital. “When you say it out loud that doesn’t sound like a lot but when you think that these are people whom in the past we had about a 7% survival (rate) and most of them would have been sent home for patient care or palliative chemotherapy,” Bacon says.

“CAR-T therapy is a lifeline for suitable blood cancer patients whose other treatment options have been exhausted,” says Bacon. “It is the most advanced immunotherapy currently available for patients with lymphoma and CAR-T therapy marks a huge breakthrough in the treatment of relapsed and refractory disease.”

Children’s Health Ireland in Crumlin is the National Paediatric CAR-T centre, and the therapy is being made available to teenagers, children, toddlers and babies.

The results from clinical trials of CAR T therapy have been most promising for blood cancers, and less so for solid tumours which are far harder for T cells to penetrate. “Approximately 75% of blood cancer patients who received CAR-T have had a complete or partial response to the therapy,” says English. “This is very impressive especially in patients for whom no other treatment option would work.”