Immunotherapy has transformed the way advanced melanoma is managed by shifting the focus from attacking cancer cells directly to empowering the body’s own natural defences. These medications work by identifying and removing the biological barriers that cancer cells use to hide from the immune system. By reactivating the body’s ability to recognise and destroy malignant cells, immunotherapy offers a powerful and long-lasting method of controlling the disease when surgery is no longer an option.
What We’ll Discuss in This Article
- The biological mechanism of checkpoint inhibitors in the body.
- Understanding the difference between PD-1 and CTLA-4 inhibitors.
- The benefits and risks of using combination immunotherapy.
- How advanced melanoma is targeted through intravenous and subcutaneous delivery.
- Recognising the common immune-related side effects of these drugs.
- The importance of genetic testing before starting treatment.
- What patients can expect during a typical course of immunotherapy.
The mechanism of checkpoint inhibition in the immune system
Immunotherapy drugs used for advanced melanoma are primarily known as checkpoint inhibitors, which function by preventing cancer cells from sending signals that turn off the immune system. In a healthy body, immune checkpoints are like natural brakes that stop the immune system from becoming overactive and attacking healthy tissues. Melanoma cells can hijack these checkpoints to appear invisible or harmless, effectively putting the immune system into a state of sleep. Immunotherapy drugs work by blocking these specific proteins, which allows the body’s T cells to recognise, track down, and destroy the cancer cells throughout the body. This process is often described by clinicians as taking the brakes off the immune response.
Understanding PD-1 and CTLA-4 protein blockers
Two of the most common targets for immunotherapy in the UK are the PD-1 and CTLA-4 proteins, which act as different types of stop buttons for immune cells. Drugs like nivolumab and pembrolizumab target the PD-1 protein on the surface of T cells, which is a checkpoint that cancer cells often use to avoid detection. By blocking this interaction, the T cells remain active and can continue to attack the tumour. Ipilimumab is a different type of drug that blocks the CTLA-4 protein, which is an earlier brake in the immune cycle that usually works in the lymph nodes. Using these drugs allows the immune system to maintain a more vigorous and sustained response against advanced melanoma.
The use of combination immunotherapy for advanced disease
For many patients with advanced melanoma, doctors may recommend using a combination of two different immunotherapy drugs at the same time. The most frequent combination used in the UK is nivolumab and ipilimumab, which targets both the PD-1 and CTLA-4 checkpoints simultaneously. This approach is designed to provide a double hit to the cancer by releasing two different types of immune brakes. While using two drugs together can be more effective at shrinking tumours and prolonging life, it is also associated with a higher risk of more severe side effects because the immune system becomes significantly more active. This decision is always made after a careful assessment of a patient’s overall fitness and the specific characteristics of their melanoma.
New developments with LAG-3 inhibitors
A more recent addition to the immunotherapy landscape in the UK is the targeting of a third protein called LAG-3. A combination drug known as Opdualag, which contains both nivolumab and relatlimab, has been approved for use in patients with untreated advanced melanoma. LAG-3 is another checkpoint that can cause T cells to become exhausted or less effective over time. By blocking both PD-1 and LAG-3, this newer treatment provides another way to keep the immune system active for longer. This offers an alternative for patients who might not be suitable for the more intense nivolumab and ipilimumab combination, but who still require a more potent treatment than a single drug alone.
Administration and dosing of immunotherapy drugs
Immunotherapy is typically administered in a hospital or specialised clinic as an intravenous infusion, which is a drip into a vein in the arm. The frequency of these sessions depends on the specific drug being used, often occurring every two to six weeks. Each infusion can take between thirty minutes and two hours to complete, during which time medical staff will monitor for any immediate reactions. In recent years, some forms of nivolumab have also become available as a subcutaneous injection, which is given just under the skin and takes only a few minutes. This variety in delivery methods allows for more flexibility in a patient’s schedule while maintaining the high levels of medication needed to fight the cancer.
Identifying and managing immune-related side effects
Because immunotherapy works by making the immune system more active, it can sometimes cause the body to attack its own healthy organs and tissues. These are known as immune-related adverse events and can affect almost any part of the body, including the skin, gut, liver, and hormone-producing glands. Common symptoms include a persistent itchy rash, diarrhoea, extreme fatigue, or a dry cough. Most of these side effects are manageable with steroid medications if they are identified early, but they can become serious if left untreated. Patients are provided with an alert card to carry at all times so that any healthcare professional they see is aware that they are receiving immunotherapy.
The role of genetic testing and BRAF status
Before starting immunotherapy for advanced melanoma, a sample of the cancer tissue is usually tested for a specific genetic change called a BRAF mutation. About half of all melanomas have this mutation, which can also be treated with targeted therapy drugs. For patients with advanced disease, immunotherapy is often recommended regardless of whether they have the BRAF mutation or not. However, knowing the BRAF status helps the oncology team decide the best order in which to use the available treatments. For those who do not have the mutation, immunotherapy is almost always the first-line choice, as it provides the most durable long-term response for many people.
Long-term outcomes and the potential for a cure
The ultimate goal of immunotherapy in advanced melanoma is to achieve a long-term remission, where the cancer is either stable or has completely disappeared. Clinical trials in the UK have shown that many patients who respond well to these drugs continue to stay healthy for many years, even after the treatment has finished. This is because the immune system can develop a memory of the cancer, allowing it to continue protecting the body long after the final dose is given. While not every patient responds to immunotherapy, the progress made with these drugs has fundamentally changed the outlook for people living with Stage 4 melanoma.
Conclusion
Immunotherapy drugs work by reactivating the body’s own immune system to recognise and destroy advanced melanoma cells. By blocking proteins like PD-1 and CTLA-4, these treatments allow T cells to fight the cancer more effectively than traditional methods. While the increased immune activity can lead to side effects, the potential for long-term disease control has made immunotherapy a primary treatment option in the UK. If you experience severe, sudden, or worsening symptoms, call 999 immediately.
What is a checkpoint inhibitor?
It is a type of immunotherapy drug that blocks proteins on cancer cells or immune cells that stop the immune system from attacking the tumour.
How long does immunotherapy treatment last?
For advanced melanoma, treatment is often continued for up to two years as long as it is working and the side effects are manageable.
Can I have immunotherapy if I am also having radiotherapy?
Yes, doctors sometimes use immunotherapy alongside other treatments like radiotherapy to help control specific areas of cancer growth.
Is immunotherapy the same as a vaccine?
No, while both involve the immune system, immunotherapy treats existing cancer whereas most vaccines are designed to prevent infections.
What happens if I miss a dose of my immunotherapy?
If you miss a scheduled session, you should contact your oncology team immediately to reschedule, as maintaining the treatment cycle is important for its effectiveness.
Why do I need to carry an immunotherapy alert card?
The card informs other medical professionals that your symptoms might be immune-related side effects, which require specific treatments like steroids rather than standard antibiotics.
Does immunotherapy work for everyone?
Not every patient will respond to immunotherapy, but for those who do, the effects can be very long-lasting compared to older types of cancer treatment.
Authority Snapshot (E-E-A-T)
This article is designed to provide clear and factual information regarding skin health for the general public. The content is written by the Medical Content Team and has been reviewed by Dr. Stefan Petrov. He is a UK-trained physician with an MBBS and postgraduate certifications including Basic Life Support (BLS), Advanced Cardiac Life Support (ACLS), and the UK Medical Licensing Assessment (PLAB 1 & 2). He has hands-on experience in general medicine, surgery, anaesthesia, ophthalmology, and emergency care. Dr. Petrov has worked in both hospital wards and intensive care units, performing diagnostic and therapeutic procedures, and has contributed to medical education by creating patient-focused health content and teaching clinical skills to junior doctors.
