How CAR-T uses the body’s own immune system to fight cancer

Special Report: A form of immunotherapy that involves modifying a patient’s white blood cells so they recognise and target cancer cells is shaping up as a potent weapon in humanity’s war against cancer.

Historically humankind has fought cancer in three main ways, says Steven Yatomi-Clarke, the chief executive and managing director of Melbourne-based Prescient Therapeutics (ASX:PTX).

We’ve cut it out through surgery, a technique that’s been around since the Dark Ages.

We’ve fried it with radiation, a treatment known as radiation therapy or radiotherapy.

And we’ve poisoned it with chemicals, in what’s known as chemotherapy, where harsh drugs are used to stop the cancer cells from dividing.

But in the past few decades, a new battlefront has emerged in the war against cancer – harnessing the body’s own immune system to target cancer cells, Yatomi-Clarke says.

This is something the body already does. If you’ve noticed your lymph nodes on the sides of your neck were swollen, that’s a sign that your immune system was hard at work battling a foreign invader – probably a virus or another infection. But they could possibly also be fighting cancer.

“If your T-cells are able to recognise these (cancer) cells, they can eliminate them, and you may never ever know about it,” Yatomi-Clarke says.

It’s when your white blood cells fail to recognise cancer cells that you might run into trouble.

Several immunotherapy treatments out there

Scientists have devised a number of ways to use the immune system to fight cancer.

In 2018, James P. Allison and Tasuku Honjo were awarded the Nobel Prize in Physiology or Medicine for their work on what are known as checkpoint inhibitors – a type of immunotherapy that blocks a “break,” or checkpoint, on the immune system.

A newer wave of immunotherapy that’s attracting attention and excitement is known as CAR-T cell therapy – short for “chimeric antigen receptor” T-cell therapy.

In a CAR-T treatment, a small portion of a patient’s own T cells – the white blood cells that are key to an immune response – are taken from their body and modified in a laboratory.

They’re engineered with “chimeric antigen receptors” that now able the patient’s own T-cells to seek out and target cancer cells.

“This is widely considered one of the biggest advances in human medicine in many decades,” Yatomi-Clarke says.

“There’s nothing more potent against cancer than a trained T cell. The patient is getting a turbocharged version of their own immune system.”

Two CAR-T therapies are already on the market, fighting two types of blood cancer.

In 2017, the US Food and Drug Administration approved Novartis’ Kymriah to treat B-cell acute lymphoblastic leukemia (ALL), a treatment invented and developed at the University of Pennsylvania.

In January the Australian government expanded access to Kymriah here, allowing the Peter MacCallum Cancer Centre in Melbourne to process patient cells for treatment.

The US FDA also in 2017 approved Yescarta, a CAR-T therapy developed by California-based Kite Pharma used to treat large B-cell lymphoma. Gilead Sciences bought Kite that year for $US11.9 billion ($16.7 billion).

Johnson & Johnson is working on a CAR-T treatment for multiple myeloma while Pfizer is investigating CAR T treatments across several targets.

CAR-T, says Yatomi-Clarke, “has provided results that we have never ever seen before – to the point that people are daring to aim beyond incremental improvement in cancer treatment, and aiming for something much more meaningful.”

Drawbacks and challenges

To be sure, the approved CAR-T treatments are incredibly expensive, costing more than half a million dollars per patient.

There are also issues with safety, since the treatment involves injecting living cells into a patient’s body.

But what’s currently on the market is version 1.0, Yatomi-Clarke says.

Future treatments could be “allogenic” rather than “autologous” – meaning they use off-the-shelf treated T cells, rather than ones from a patient’s own body. This could increase access for patients. Future treatments will also be controllable and adaptable, unlike current generation CAR-T.

His company has licensed a next-generation CAR-T platform from the University of Pennsylvania – the same leader in CAR-T that developed Kymriah – to try and solve some of these issues and make CAR-T treatments safer and able to address a range of cancers outside the abilities of current CAR-T.

“I think Australia should be proud that Prescient has been able to get a hold of this amazing platform,” he says.

This article was developed in collaboration with Prescient Therapeutics, a Stockhead advertiser at the time of publishing.

This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.