Mesothelioma immunotherapy uses checkpoint inhibitor drugs that switch the immune system back on so it can attack the cancer. According to the National Cancer Institute, that same immune activity can also turn on healthy tissue, causing fatigue, skin rash, diarrhea, and thyroid or other hormone changes. Most reactions are manageable, but some are serious and need prompt medical care.
If your loved one was just started on immunotherapy, the side effects can feel different from anything you read about chemo. They are. Here is a plain-language guide to what to watch for, what is normal, and when to pick up the phone. Always follow your own oncology team first; this page is here to help you ask better questions.
What are the side effects of Opdivo plus Yervoy for mesothelioma?
The FDA approved nivolumab (Opdivo) plus ipilimumab (Yervoy) as a first-line treatment for pleural mesothelioma that cannot be removed with surgery. Both are checkpoint inhibitors. According to the National Cancer Institute and the American Cancer Society, the most common side effects of this combination include:
- Fatigue, the most frequently reported effect.
- Skin changes such as rash or itching.
- Diarrhea or inflammation of the colon (colitis).
- Thyroid and other hormone (endocrine) changes.
- Nausea or reduced appetite.
- Muscle, joint, or bone aches.
Because two drugs are combined, immune side effects can show up a little more often than with one checkpoint inhibitor alone. That is a trade your oncology team weighs on purpose, and they will watch your bloodwork closely for it.
What about Keytruda?
Pembrolizumab (Keytruda) is another checkpoint inhibitor. Recent evidence supports using it in combination with chemotherapy for pleural mesothelioma, and your oncologist may raise it depending on your case. Because Keytruda works on the immune system the same way Opdivo does, the American Cancer Society notes its side effect pattern is broadly similar: fatigue, rash, diarrhea, and hormone changes are the kinds of effects to expect, and the serious immune reactions below can happen with it too. Ask your team which specific regimen they are recommending and why, so you know what to monitor. Our treatment innovations page explains where these drugs fit in the bigger picture.
How are immune-related side effects different from chemo side effects?
This is the part families most often get wrong, so it is worth slowing down on. Chemotherapy works by killing fast-dividing cells, which is why it tends to cause hair loss, low blood counts, and nausea on a fairly predictable schedule. Immunotherapy works differently. It removes the brakes on your immune system, and the National Cancer Institute explains that the side effects come from the immune system attacking healthy tissue, not from the drug being toxic to cells directly.
That difference matters in three practical ways. Immune side effects can appear in almost any organ. They can show up weeks or even months into treatment, sometimes after a dose. And they often need a different fix: instead of stopping at supportive care, serious immune reactions are usually treated with steroids or other medicines that calm the immune system back down.
| Chemotherapy side effects | Immune-related side effects | |
|---|---|---|
| Underlying cause | Drug kills fast-dividing cells | Immune system attacks healthy tissue (per NCI) |
| Common examples | Hair loss, low blood counts, nausea | Fatigue, rash, diarrhea/colitis, thyroid changes |
| Timing | Often predictable, dose-by-dose | Can appear weeks to months in, less predictable |
| Typical management | Supportive care, dose timing | May need steroids or holding the drug (per ACS) |
| Who decides changes | Your oncology team | Your oncology team |
Educational comparison only. Your care team decides what applies to you.
Which side effects are serious, and when should we call the doctor?
Most side effects are mild and manageable, but a smaller number signal that the immune system is inflaming an organ, and those need prompt attention. The American Cancer Society advises patients on checkpoint inhibitors to report new or worsening symptoms quickly, because early treatment usually keeps them from becoming severe. Call your care team right away for things like:
- Diarrhea that is frequent, watery, or has blood in it, or belly pain.
- A cough, shortness of breath, or chest pain that is new or getting worse.
- Yellowing of the skin or eyes, or pain on the right side of the belly.
- A rash that is spreading, blistering, or peeling.
- Severe tiredness, dizziness, headaches, or vision changes.
- Feeling very thirsty, urinating a lot, or unusual weight changes (possible hormone effects).
You will not be bothering anyone by calling. Oncology teams running immunotherapy expect these calls and would much rather hear about a symptom early. For any sudden, severe, or life-threatening symptom, such as trouble breathing, call 911. When you call the office, it helps to say the patient is on immunotherapy or a checkpoint inhibitor, so the team knows to think about an immune reaction.
How are these side effects managed?
Management depends on how serious the reaction is, and your oncology team leads every decision. In general terms, the American Cancer Society describes an approach along these lines. Mild effects, such as a little fatigue or a small rash, are often handled with supportive care while treatment continues. More bothersome effects may mean pausing the drug until things settle. Serious immune reactions are usually treated with steroids or other medicines that quiet the immune system, and sometimes the drug is stopped for good.
Hormone changes, like an underactive thyroid, are common enough that they are often managed simply by replacing the missing hormone, and treatment can frequently continue. The key on your side is reporting symptoms early and keeping every lab appointment, because routine bloodwork is how the team catches some of these changes before you feel them. Choosing a center that treats mesothelioma often helps too; our find a mesothelioma specialist page can point you toward experienced programs.
How long do they last?
There is no single answer, and you should ask your own team about your specific case. Broadly, many milder effects ease once a dose is paused or the body adjusts. Some, like fatigue, can linger through treatment. Hormone changes, such as a thyroid that has slowed down, can be lasting and may need hormone replacement going forward, even after immunotherapy ends. Because checkpoint inhibitors keep the immune system more active, the National Cancer Institute notes that immune-related effects can sometimes begin or continue after the last dose, which is why your team keeps monitoring you for a while. The honest takeaway: most people get through immunotherapy with manageable side effects, and your care team adjusts the plan as they go.
You do not have to figure this out alone. A patient advocate can help your family understand treatment costs, find an experienced mesothelioma program, and learn what financial help you may qualify for, at no cost to you.
Call 24/7: 1-800-877-6000 · or check your eligibility in 3 questions.
If the cost of care is part of the worry, our guide to financial assistance for mesothelioma explains the help that may be available, including asbestos trust funds.
Written by Larry Gates, Senior Client Advocate. Larry is a patient advocate, not a medical professional, and this article reflects experience supporting families, not clinical advice. MesoCare is a patient-and-family resource sponsored by Danziger & De Llano. This article is for general education only and is not medical or legal advice. Always follow the guidance of your own oncology team, and call your care team or 911 for urgent symptoms.
Sources
- National Cancer Institute (cancer.gov): immune checkpoint inhibitors and immune-related side effects; mesothelioma treatment.
- American Cancer Society (cancer.org): immunotherapy side effects and managing immune-related reactions.
- U.S. Food and Drug Administration (fda.gov): labeling and approval of nivolumab (Opdivo) plus ipilimumab (Yervoy) for unresectable pleural mesothelioma; pembrolizumab (Keytruda).
- (Re-verify all source URLs at publish.)