How Immunotherapy Is Revolutionizing Cancer Treatment and Beyond

How Immunotherapy Is Revolutionizing Cancer Treatment and Beyond

Over the past decade, clinical trials exploring immunotherapy have surged dramatically, as scientists have translated deep knowledge of the human immune system into groundbreaking medical treatments. While cancer therapies remain at the forefront of this revolution, researchers are rapidly expanding the scope of immunotherapy to address a wide spectrum of conditions — including infections, allergies, neurological diseases, and autoimmune disorders.

What Exactly Is Immunotherapy?

Immunotherapy refers to a category of biological treatments designed to harness, guide, or modify the immune system to prevent and fight disease. Vaccines are perhaps the most widely recognized form — they teach the immune system to identify and respond to specific threats, such as viruses or bacteria. Beyond vaccines, some immunotherapies work by amplifying immune responses that are too weak to combat illness effectively, while others suppress overactive immune reactions that cause the body to attack itself. Additional approaches leverage engineered immune cells or laboratory-produced antibodies to intervene in disease processes at a molecular level.

Although the concept of strengthening the body's defenses to ward off disease has ancient roots, sophisticated immunotherapies targeting a broad range of conditions have only truly emerged in the last two decades. A global clinical trials registry recorded 1,257 immunotherapy trials between 2006 and 2016 — a number that surged to 4,591 in the following decade alone.

"It's really exciting. People are starting to realise just how important the immune system is," says Adrian Liston, an immunologist and professor of pathology at the University of Cambridge. "This is the era of immunology."

Immunotherapy and Cancer: A Paradigm Shift

Cancer patients have been among the greatest beneficiaries of immunotherapy advances. Dozens of approved treatments now exist for more than 30 types of cancer. One key challenge in treating cancer is that many tumors actively evade the immune system by effectively switching off the immune cells sent to destroy them. A class of antibody-based drugs known as checkpoint inhibitors can reverse this process, reactivating immune cells so they can once again identify and attack malignant tissue. Highly mutated cancers like melanoma tend to respond especially well to this approach, though outcomes vary significantly from patient to patient.

Understanding why some patients respond powerfully to immunotherapy while others see little benefit is a major research priority. A newly launched four-year study aims to recruit thousands of patients with breast, bladder, kidney, and skin cancers to identify the key factors that determine treatment outcomes.

Antibody-Based Therapies and Cancer Vaccines

Not all antibody-based cancer therapies work through checkpoint inhibition. The drug Herceptin, for example, attaches directly to breast and stomach tumors, flagging them for immune destruction while simultaneously blocking chemical signals that would otherwise stimulate tumor growth.

Cancer vaccines represent another area of enormous promise. Drawing on the same mRNA technology platform that powered the COVID-19 vaccines, more than 100 cancer vaccines are currently being evaluated in clinical trials. These vaccines are designed to prime the immune system to seek out and destroy tumor cells.

Engineering Immune Cells to Fight Cancer

Researchers are also exploiting immune cells directly in their fight against cancer. In a landmark 2018 case, doctors treated a woman with metastatic breast cancer by extracting immune cells that had naturally infiltrated her tumors, cultivating billions of those cells in laboratory conditions, and then reintroducing the most effective ones back into her body.

Another powerful approach, known as CAR-T-cell therapy, involves genetically engineering a patient's own immune cells to specifically target and eliminate cancer cells. The therapy gained public attention recently when actor Sam Neill — best known for his role in Jurassic Park — announced he had been declared cancer-free following CAR-T-cell treatment for stage 3 blood cancer as part of a clinical trial.

"We increasingly see cancer as something that's shaped by the immune system," says Samra Turajlić, director of the Cancer Research UK Manchester Institute and head of the cancer dynamics laboratory at the Francis Crick Institute in London. "In fact, the appearance of cancer is a failure of the immune system to eliminate it in the first place."

Beyond Cancer: Treating Allergies, Depression, and Autoimmune Disease

While cancer immunotherapies generally aim to intensify immune activity, therapies for many other conditions work in the opposite direction — calming an overactive immune response.

Allergy treatments, for instance, work by gradually exposing patients to tiny, incrementally increasing doses of the proteins responsible for their allergic reactions. This desensitization approach is used for conditions ranging from hay fever to peanut intolerance. A recent clinical trial in China even explored whether feeding patients pancakes could help alleviate egg allergies.

Researchers are also investigating whether existing immunotherapies originally developed for one condition might benefit patients with entirely different diagnoses. A team in Bristol recently trialed tocilizumab — an immunotherapy drug approved for rheumatoid arthritis — in patients suffering from depression. Although the study was limited in size, early results hinted at improvements in depression severity, fatigue, anxiety, and overall quality of life.

The Rise of Regulatory T-Cell Therapies

Some of the most exciting developments in immunotherapy stem from research that earned last year's Nobel Prize — specifically, work centered on regulatory T-cells, commonly referred to as Tregs. While the immune system contains many different cell types dedicated to attacking pathogens, Tregs perform a unique function: they signal the immune system to stand down once a threat has been neutralized.

Adrian Liston, who co-founded a Cambridge-based biotech startup called Aila Biotech, is currently developing a Treg-based therapy for multiple sclerosis — a condition in which immune cells mistakenly attack the body's own nervous system. His team's approach aims to boost Treg activity within the brain to halt this self-destructive immune assault. The same mechanism, he notes, could potentially be applied to reduce dangerous swelling following traumatic brain injury.

A New Frontier for Tregs

The therapeutic potential of Treg-based treatments extends well beyond multiple sclerosis. Treatments targeting Tregs are currently in development for dementia, type 1 diabetes, rheumatoid arthritis, lupus, and chronic inflammation. At Monash University, researcher Peter Eggenhuizen is developing a Treg therapy specifically designed to treat inflammatory bowel disease — a condition that affects at least 7 million people worldwide.

The Immune System: Medicine's Next Great Frontier

"Probably half of all deaths have a component that is immunological," says Liston. "It is an underlying theme across ageing, autoimmune diseases, allergies, infectious diseases, inflammatory diseases like diabetes. But one of the great things about the immune system is that it is very easy to change. We can adapt it to our purposes."

As clinical trials continue to multiply and our understanding of immune biology deepens, immunotherapy stands poised to redefine what is medically possible — offering new hope to millions of patients across a vast range of conditions that were once considered difficult or impossible to treat.