CAR-T CELLS: THE FRONTIER OF CANCER

Cancer is arguably the most costly disease in the 20th century, causing 16% of all deaths worldwide and costing $1 trillion dollars on the healthcare system annually, according to the WHO. It is a very common disease, with fatal consequences and no clear-cut, effective cure.

Attempts to reduce the death rate of cancer patients have been done via surgery, chemotherapy and radiotherapy. Although these medical innovations have reduced the death rate by 23% in 21 years, cancer is still responsible for 9 million deaths per year. However, progress has been made to deal with aggressive types of cancer in the form of CAR-T cells.

Why is cancer so deadly?

Cancer cells are formed from malignant tumours, and these cells can break lose from the primary tumour and form secondary tumours elsewhere in the body via the bloodstream. This metastasis makes cancer hard to treat and is the key to its deadliness. It is like dropping a bag of rice all over the floor, and you have to clean and pick up every grain form each and every crack and crevice. This is the same with cancer; if it isn’t fully eliminated it will crop up again.

To aggravate the problem even further is that our own immune system finds it hard recognising cancer cells due to the fact that they are our very own cells! Therefore, our immune system can’t lead an effective response towards killing cancer cells, as they disguise themselves as being one of us. Sometimes our own bodies even go as far as protecting cancer cells from chemicals used in chemotherapy.

What are CAR-T cells?

As every medical acronym does, this has a very complicated name. CAR-T cells are called chimeric antigen receptor T-cell therapy. Normal T-cells are white blood cells that are soldiers in the immune army, and they help to eliminate diseases by binding onto antigens of pathogens and release chemicals that destroy the disease. CAR-T cells are customised to zero in on a patients specific kind of cancer. Through genetic engineering of T-cells they recognise cancer cells as dangerous and foreign. This is all specified to the specific cancer cells the patient has. This form of treatment (using the patients own immune system) is called immunotherapy.

The procedure:

  1. A machine is used to extract patients’ blood, and separates T-cells.
  2. They are then mixed with ‘disarmed’ viruses that are engineered to produce a specific type of receptor on the T-cells surface. This is the chimeric antigen receptor.
  3. This is then injected into the patient intravenously to allow the T-cells to work for extended periods of time.

How do CAR-T cells work?

These genetically engineered receptors allow what was previously impossible to be done with ease. They now easily find, recognise and destroy cancer cells, like they would  to any other pathogen. They attach the artificially engineered receptors on to the CD19 antigen of cancer cells, injecting them with poisons, thus destroying the cancer. In labs they replicate millions of these white blood cells, and they can multiply and live within the body, providing long-term relief.

Is this a hoax?

Since this recent breakthrough has been discovered there have been many clinical trials, especially for leukaemia on children and adults alike. This has seen unprecedented success against stubborn cases of reoccurring cancer that failed to respond to traditional methods. A study in April 2016 in the USA showed an overall remission rate of 83% within 3 months out of 63 patients.

Not only is this successful on leukaemia, but lymphoma (cancer of lymph glands) but are now being used on solid tumours, with positive results against prostate cancer. This is now FDA approved in the USA and has been introduced in the UK, in three hospitals.

Many leading scientists (such as Dr Brent Jens of Memorial Sloan Ketting Cancer Centre) who were at first sceptical have said that “cohorts of patients who were considered terminal” are now living a “good quality of life for up to 5 years.”

Problems

With every thing that seems too good to be true, usually there is a catch, and this is no different. It seems that there is a potential and dangerous side-effect called cerebral edema (swelling of the brain), and has unfortunately led to a few deaths. However, more recent CAR-T cell studies have found no such instances of the complication.

The second downside is obviously the cost. CAR-T treatment has a price list of £282,000 per patient, and especially with the NHS’s limited pot of money it will be difficult for choices to be made. However, the funds for CAR-T will come from the Cancer Drugs Fund to provide fast access to the most promising new cancer treatments. The deal that the NHS has made means patients who are up to 25 years old who have advanced B-cell acute lymphoblastic leukaemia are eligible to use it.

Overall, I feel this is the only way forward in finally ending the tragic war against cancer. It is ground-breaking, and only has the potential to further improve the lives of many individuals.

“In the nest few years, I think we’re going to see dramatic progress and push the boundaries of what many people thought was possible with these adoptive cell transfer –based treatments” Dr Steven Rosenberg, Chief of the Surgery NCI.

Rushil Shah

Photo Credits due to: Rushil Shah