April 19, 2024

I, Science

The science magazine of Imperial College

Sulagna Maity investigates the possibilities of immunotherapy as a cancer treatment.

(By Sulagna Maity on 13th December 2023)

Cancer! People get terrified when they hear this term. But why? Is it because of its possibility of recurrence? Its lack of a permanent cure? The potential to cause death in the final stages? Whatever the reason is, people often fear cancer over many other diseases. There are several prevalent treatments such as chemotherapy or radiation, however, these therapies are often a “curse in disguise”. A report by Cureus in 2023 showed that 97.4% of patients experienced at least one side effect in a six-month follow-up period after chemotherapy, with fatigue, loss of appetite and diarrhoea being the most common. Radiation or chemotherapy are commonly used treatments, but they do not always kill all the cancerous cells. Perhaps this is where the scariest part falls for many people: Cancer has a habit of resuming if there are even a few malignant (cancerous) cells left in the body.

In recent years, immunotherapy has emerged as a promising therapeutic strategy for cancer. Immunotherapy is a process where a person’s immune system is used to fight against cancer with fewer side effects than chemo and radiotherapy. Cancers that are caused by viruses have found the remedy in the form of vaccination. For example, the HPV vaccine is recommended for children aged between 12-13 years to prevent cervical/uterine cancer caused by Human Papillomavirus. Apart from vaccination, immunotherapy includes monoclonal antibodies, immune checkpoint inhibitors, and CAR T-cell therapy.

Antibodies are proteins made by our immune system that recognise and bind to specific proteins called antigens, usually from a pathogen or parasite. Monoclonal antibody therapy uses laboratory-made antibodies to help the immune system target a particular protein or antigen on the surface of a cancer cell. Once they bind to the antigen, they can either directly destroy the cancer cell or indirectly signal the immune system to attack it. Monoclonal antibodies can be modified to target specific cancer cells while sparing healthy cells, resulting in fewer side effects than traditional chemotherapy. Immune checkpoints are like stop signals, suppressing overactivation of the immune system. However, cancer cells often escape the immune system’s detection by activating checkpoints. Immune checkpoint inhibitors work by blocking certain proteins on the cancer cells that usually activate these checkpoints. This allows the immune system to better identify and attack cancer cells, which can lead to improved outcomes for cancer patients. Finally, CAR T-cell therapy has currently become a revolution in the medical field. So, how does it work? Doctors take T-cells (a type of immune cell) from the patients’ blood and genetically modify them in the laboratory to produce special receptors called Chimeric Antigen Receptors or CARs on their surface. These modified T-cells are infused back into the patients’ blood where these cells multiply and attack cancer cells. This therapy has been effective even in some patients who failed to respond to other treatments.

Figure made by Sulagna Maity in BioRender

However, according to MD Anderson Cancer Centre (University of Texas, USA), immunotherapy may not work for every cancer because tumours can develop mutations (changes in the genetic material) in some cases, thus blocking T-cells from recognising and attacking cancer cells. Moreover, as we grow older, the production of our immune cells is diminished, and our immune system becomes less efficient to respond to pathogens and cancer: a natural process called immunosenescence. So, a question arises: are immunotherapies effective in older patients?  Older patients remain underrepresented in most clinical trials and so further investigation is required to evaluate the correlation between older cancer patients receiving immunotherapy and their outcome.

Immunotherapies have positive outcomes for many, but whether or not they are cost-effective is a different issue.  The cost of immunotherapy in India is Rs. 1,50,000 to 4,50,000 (approximately £1400 to £4300) per session. In the UK, a single round costs £30,000. A recent report in Pharmacy Times published that the total cost of CAR T-cell treatment can exceed $1 million (approximately £790, 000). If the cost increases every year, patients may revert to traditional therapy (chemo and radiation) and the objective of immunotherapy could eventually become futile. In 2023, ImmunoACT (an IIT-Bombay incubated company in India) announced that they were granted approval for CAR T-cell therapy to be used in blood cancer patients. They claimed that this therapy is “affordable”. The approximate cost would be between Rs. 30 lakhs to 40 lakhs per patient (approximately £28,500 to £38,100). Yes, it is “affordable” only if the average person avails a loan and goes into huge debt!

To sum up, we are still stuck between the side effects of current treatments and the price of new ones. Discoveries are indeed leading ways to fight against cancer. We cannot deny the contributions of Noble Laureates, James P Allison and Tasuku Honzo, for their pioneering work on cancer immunotherapy. Though expensive, immunotherapy is indeed the game changer for cancer and is likely capable of terminating the existence of cancer someday and the fear surrounding it. But these new therapeutics should be available and affordable to everyone so that we can hope for a cancer-free world in the impending future.

Feature image credit: Photo by National Cancer Institute on Unsplash