Starting Immunotherapy: What to Expect

Medically Reviewed by Stephanie S. Gardner, MD on September 18, 2023
5 min read

If you’ve been diagnosed with metastatic melanoma, that means the cancer has spread from your skin to other areas of your body. Your doctor may recommend immunotherapy. This treatment doesn’t kill cancer cells directly. Instead, it helps your own immune system to better fight the disease.

The most common type of immunotherapy for metastatic melanoma is what’s known as a checkpoint inhibitor. These drugs take the brakes off your body’s immune system to allow T-cells, which recognize and destroy cancer, to do their job.

The newest types of immunotherapy drugs are called checkpoint inhibitors:

Pembrolizumab (Keytruda)

All of these drugs are immune checkpoint inhibitors. They help boost immune responses that could help fight cancer cells.

Like traditional chemotherapy, you get immunotherapy with an IV into a vein in a doctor’s office, clinic, or outpatient unit in a hospital. That means you won’t have to spend the night in the hospital.

How often and how long you’ll get immunotherapy depend on:

  • What type of cancer you have and how advanced it is
  • What type of treatment you get
  • How your body reacts to the therapy

Generally, you’ll go in every 2-3 weeks for an IV infusion. The drugs are given in cycles. That means you’ll get treatment for a while, then have some time off to let your body rest, respond to the treatment, and create new healthy cells.

No two people respond the same way. What happens to you depends on your health before you started, how advanced your cancer is, and the type and dosage of treatment you’re getting.

Traditional chemotherapy can cause hair loss and blood problems. But immunotherapy drugs don’t work in the same way.

When your immune system is on high alert, it may start to attack other body parts like your skin. If it does, you could get an itchy rash and loss of skin pigmentation. Infections may also occur. You might notice more serious side effects if your immune system goes into overdrive and starts to attack healthy tissues. This can lead to diabetes, and inflammation of your bowels, pancreas, and lungs. Rarely, there have been neurological problems such as Guillain-Barre syndrome and myasthenia gravis, and even fatal reactions from heart attack, lung toxicity, and liver injury.

If it affects your intestines, you might get diarrhea. The severity of side effects varies. Some people have mild to moderate symptoms, while others can have major problems. One popular treatment -- a mix of two checkpoint inhibitors: ipilimumab (Yervoy) and nivolumab (Opdivo) -- often causes severe fatigue and loss of appetite. This can seriously affect your quality of life.

Some treatments cause side effects so subtle that you barely know you’re having them. For example, the organs that make up your endocrine system, like the thyroid and pituitary, could get inflamed. Your doctor may not even know it’s happening unless they do a blood test.

Unlike chemotherapy, where side effects usually show up right away, immunotherapy doesn’t cause a reaction until you have a few doses under your belt. The timing varies, but it’s usually within the first 3 months but after the first 3 weeks of therapy.

For most people, steroids can help manage the symptoms and not stop the drugs from working. Topical corticosteroid creams and oral antihistamines can often give quick relief for skin symptoms. Over-the-counter treatments should work for mild diarrhea as well.

High-test steroids like prednisolone or other drugs that suppress your immune system are also the choice to treat most other problems, which you may hear your doctor refer to as adverse events, or AEs.

In addition to steroids, you might have to take permanent hormone supplements after being on this type of treatment. If the symptoms are too severe, your doctor may pause your treatment for a while. But if you have a life-threatening reaction, you’ll need to stop treatment.

Everyone’s different, so there’s no rule for when side effects will show up. Skin problems can appear 2 to 3 weeks after the first dose of the drug, gastrointestinal problems may take 6 to 7 weeks, and endocrine problems may not affect you for more than 2 months. Some people don’t have side effects until months after treatment ends.

The good news: Most side effects go away when you’re done. But even during treatment, there are ways to manage them. Let your doctor know so they can help.

Tell them how the symptoms are affecting your daily life. Don’t feel like you’re complaining. You aren’t. You’re sharing vital information they need to do their job well and to improve your quality of life.

These drugs don’t work for everyone with melanoma. Scientists are hard at work to figure out why and pinpoint the differences between patients who respond and those who don’t.

One reason why they may work better for some people than others: Doctors think tumors that have the most DNA damage are more likely to respond to these drugs. This makes sense: The mutant molecules stick out on the surface of the tumor cell, making it easier for the immune system to recognize them as foreign.

This means the drugs may work best with melanomas caused by too much DNA-damaging UV radiation. These findings could lead to diagnostic tests that identify which patients are most likely to benefit from these therapies.

Then again, there isn’t a direct cause and effect at play. Generally, the more mutations you have, the better your response will be. But not always. Some people don’t have a lot of genetic mutations but respond well. Scientists believe that other -- and as yet undiscovered -- checkpoints may be the cause.

Or your immune system may need a little more help spotting cancer cells so it can destroy them. Pairing these immune-based anti-cancer drugs, like a mix of ipilimumab and pembrolizumab, might work better. Studies showed a good response rate, and doctors got the FDA’s OK to use the combo in 2015.

There’s still some guesswork involved in figuring out who will respond best. Doctors don’t want to withhold what could be a life-saving treatment, so they’re more willing to try the drugs and watch you closely to see if they can help.

Here’s something else to think about before you try them: It’s rare, but the cure may be worse than the disease. Immune therapy can affect other organs and organ systems. Your doctor will take all this into account before they put you on this type of treatment.