February 12, 2024
📰 FEATURE STORY
Is CAR T-cell therapy the future of cancer treatment?
The road to developing effective cancer treatments continues. In 2022, US President Joe Biden launched the latest phase of the Cancer Moonshot initiative to reduce the cancer death rate by half within 25 years and improve the lives of people with cancer and survivors. Part of this involves the role people can play by getting screened and participating in research.
Concerning treatments, there have been a host of new ones, with some showing promise. One treatment of note is the Chimeric Antigen Receptor (CAR)-T cell therapy. The basic premise is genetically modifying a patient’s T-cells to recognise and attack cancer cells. It has been called a revolutionary new pillar in cancer treatment. Does it represent the long-term future?
Context
In cancer treatment, immunotherapy has been transformative, particularly for those with late-stage metastatic cancers. It was named “Breakthrough of the Year” by Science Magazine in 2013. Its origins go back to the 1860s. Physicians in the late 1800s pioneered treatments like ‘Coley’s Toxins’, named after bone surgeon and cancer researcher Dr William B Coley.
However, this treatment was discontinued once radiation and chemotherapy came to the fore. The concept of a chimeric T-cell receptor originated in 1987. Japanese immunologist Dr Yoshikazu Kurosawa and his team at the Institute for Comprehensive Medical Science in Aichi, Japan, undertook a landmark study. T-cells are a type of white blood cell part of the immune system and are developed from stem cells in the bone marrow. They can help fight cancer.
Cancer cells and other foreign substances in the body have proteins on their surfaces called antigens. T cells and other immune system cells have proteins called receptors. Antigens and receptors fit together. Each antigen has a unique immune receptor to bind to.
Here’s how things usually go. When the immune system recognises foreign or abnormal antigens, it works to destroy them. However, cancer cells sometimes have antigens the body doesn’t see as abnormal. So, T cells aren’t sent to fight the cancer cells.
Here’s how CAR T-cell therapy works. A patient’s T cells are collected and modified in a lab to ensure their immune cells have adequate receptors to bind to the right antigens to effectively destroy cancer cells. In the lab, a specific gene for a specific receptor is added called the Chimeric Antigen Receptor (CAR). The modified T cells are reintroduced into the patient to begin their fight against cancer cells.
The US Food and Drug Administration (FDA) has approved six CAR T-cell therapies. They are used to treat Leukemia, Lymphoma, and Multiple myeloma. Last year, India’s Central Drugs Standard Control Organization (CDSCO) issued market authorisation for CAR-T cell therapy. The company ImmunoACT, incubated at IIT Bombay, developed the treatment called NexCAR19.
How promising is this relatively new treatment? Is it the future of cancer care?
VIEW: A lot of potential
Initial trials for some types of cancers were successful. Among the most promising ones is CD19-expressing blood cancers conducive to CAR T-cell therapy. Unlike other therapies, since CAR-T cells are engineered to specifically recognise and target cancer cells, there’s a high degree of specificity. Other treatments like immune checkpoint inhibitors and cancer vaccines rely on modulating the patient’s immune system and struggle with efficacy.
For practical purposes, they’ve shown encouraging response rates in treating malignancies like refractory acute lymphoblastic leukaemia (ALL). This therapy also has what some call the “living drug” nature of CAR T-cells. This allows them to persist and expand in the patient, providing a sustained antitumour response. This isn’t the case in other therapies.
The reason why many are optimistic about this form of therapy is because of its effectiveness. It does a good job of only attacking cancer cells and not healthy ones. So, it doesn’t have the same side effects as chemotherapy. One of the encouraging signs for CAR T-cell therapy is there’s further scope to optimise the CAR T-cell design and delivery. It raises the hope of a cure for more people with malignancies and ushers in a new era in cancer treatment and immunotherapy.
COUNTERVIEW: Not without its challenges
While there have been successful trials in relapsed or refractory haematological malignancies, CAR T-cell therapy still hasn’t proven itself in the treatment of solid tumours. The cellular structure of solid tumours prevents the infiltration of CAR-T cells. Additionally, solid tumours rarely express one tumour-specific antigen. They usually have tumour-associated antigens (TAAs). There’s no near-term benefit to deploying CAR-T cell therapies in solid tumours by just repeating the technique used in blood cancers.
Some of the most challenging drawbacks of this form of therapy are adverse events. The most frequently documented is cytokine release syndrome (CRS). These effects range from mild fever and hypotension to the extremes of multi-organ failure and seizures. Decreased blood counts are also observed in some patients.
In India, cancer kills about 8 lakh people every year, and the treatment is very expensive for most of the population. CAR T-cell therapy is no different. The homegrown CAR T-cell therapy costs about a tenth of the treatment in the US. However, that’s about ₹40 lakh. In the US, treatment can cost over $400,000. CAR T-cells are expensive to produce due to their patient-specific nature and complex manufacturing process.
Reference Links:
- CAR T-Cell Therapy Remains a Promising Therapeutic Option Despite FDA Inquiry into Secondary Malignancies – Oncology Nursing News
- India’s first cell therapy for cancer treatment receives regulatory approval – Hindustan Times
- CAR-T cell therapy: current limitations and potential strategies – Nature
- Scientists are making CAR-T cells more clever. Here’s what the next generation could look like – STAT
- The Boundless Potential of CAR T Cell Therapy, From Cancer to Chronic and Common Diseases – Penn Medicine
- Express View on India’s CAR T-cell therapy: Taking cancer on – The Indian Express
What is your opinion on this?
(Only subscribers can participate in polls)
a) CAR T-cell therapy is the future of cancer treatment.
b) CAR T-cell therapy isn’t the future of cancer treatment.
🕵️ BEYOND ECHO CHAMBERS
For the Right:
Uttarakhand Uniform Civil Code draws significantly from Hindu law – and barely represents others
For the Left:
Attempts by Karnataka Congress to mimic Hindutva methods are morally dubious