CAR T-cell therapy can be a very successful treatment for relapsing refractory multiple myeloma. But it can also be hard on your body with serious and sometimes life-threatening side effects.
That’s why it must be done at certain medical centers. It’s also why the FDA requires you to either stay at or live within 15 minutes of the medical center for 30 days after treatment. Here are some of the potential complications and how to manage them.
Cytokine Release Syndrome (CRS)
As CAR T cells multiply in your body, they release chemicals called cytokines into your bloodstream. Cytokines boost your immune system, but too many can send your immune system into overdrive. CRS can trigger dangerous symptoms like:
- High fever
- Trouble breathing
- Severe nausea, vomiting, or diarrhea
- Feeling dizzy
- Headaches
- Fast heartbeat
- Extreme fatigue
- Muscle and/or joint pain
On average, CRS starts 2 to 3 days after CAR T-cell therapy, but it can also start up to 14 days after treatment. If you have a mild case, the doctor will probably give you:
- Antihistamines
- Anti-vomiting drugs
- Fluids through an IV
They’ll watch you closely to make sure you don’t get worse.
If your condition is more severe, you’ll likely be treated with a drug like tocilizumab. It targets cytokines in your body and calms them down. It’s usually given through an IV. You may also be given a steroid.
Problems With Your Brain and Nervous System
CAR T-cell therapy can also harm your brain and nervous system. This is called immune effector cell-associated neurotoxicity syndrome, or ICANS. It occurs in up to 70% of those who do CAR T-cell therapy. It’s not clear why ICANS happens.
Researchers think inflammation from CAR T-cell therapy and high levels of cytokines activate the cells that line your brain’s blood vessels. When this happens, it impacts your brain function. Symptoms include:
- Severe confusion
- Behavior changes
- Hallucinations
- Seizures
- Impaired speech
- Headache
- Tremors
- Trouble writing
Eventually, ICANS can lead to brain swelling, coma, and even death. Symptoms usually start 3 to 10 days after CAR T-cell therapy. You may have trouble focusing and talking. Tell your doctor or nurse right away if this happens. The good news is more serious symptoms are rare and affect less than 10% of people who go through CAR T-cell treatment.
The best treatment is steroids, especially dexamethasone. It enters the central nervous system more easily than other drugs. Your doctor may also give you antiseizure medication to ward off and treat seizures.
Most people who get ICANS after CAR T-cell therapy recover and have no long-term brain or central nervous system damage. But because there’s a chance you could have these side effects, it’s recommended that you not drive for several weeks after CAR T-cell treatment.
Allergic Reactions
There have been a few reports of serious allergic reactions while getting CAR T-cell treatment. This is called anaphylaxis. Symptoms include:
- Hives
- Facial swelling
- Low blood pressure
- Trouble breathing
Your medical team will watch you closely during infusion to make sure you’re not having any sort of a reaction.
A Weakened Immune System
You’re more likely to get a serious infection after CAR T-cell therapy because it curbs your immune system. One study found that more 40% of those who did CAR T-cell therapy got an infection within 30 days after treatment. After 30 days, just over 30% were diagnosed with an infection within the first 6 months. Your doctor may recommend that you take medication for several months after treatment to help avoid infection.
Some people also see a lower white blood cell count. Your medical team will watch yours closely. If they’re low, they may recommend injections of drugs known as growth factors to increase production.
Electrolyte Imbalances
Your levels of potassium, sodium, or phosphorus may be lower after CAR T-cell therapy. One study found that about half of the participants had low sodium levels after treatment, a condition called hyponatremia. This can cause the cells in your body to swell up with extra water. That’s very dangerous, especially in your brain. Your medical team will monitor your blood chemical levels very carefully in the days and weeks following treatment.
How Do I Manage These Potential Side Effects?
Since there are so many potentially serious side effects that can occur with CAR T-cell therapy, you’ll stay close to your treatment center for 30 days. You’ll go in every day to be checked for:
- Low blood counts
- Infection
- Electrolyte imbalances
- Symptoms of CRS or ICANS
You may be admitted to the hospital if any of these happen.
You’ll likely still be in recovery after your 30 days are up. You may feel very tired, weak, and have problems with memory and concentration. Talk to your medical team about how soon you can return to work or school, and drive.
You’ll also have to be careful about protecting yourself from infections until your immune system is back to normal. Your medical team may recommend that you:
- Wash your hands frequently, especially before eating, after you go to the bathroom, and when you return from outdoors.
- Avoid large crowds.
- Stay away from people who are sick.
- Don’t swim in ponds or lakes.
- Disinfect your kitchen counters and bathrooms daily.
- Get your flu, shingles, and COVID vaccines. Talk with your doctor about the best time to get them.
It’s also important to stay up to date on doctor visits. Your medical team may want you to visit the cancer center where you got your CAR T-cell therapy every 2 to 2 months for a year. Of course, you should call 911 or go the nearest emergency room in between appointments if have life-threatening symptoms.
Show Sources
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SOURCES:
UptoDate: “Cytokine Release Syndrome,” “Immune Effector Cell-Associated Neurotoxicity Syndrome (ICANS).”
National Cancer Institute: “CAR T Cells: Engineering Immune Cells to Treat Cancer.”
American Cancer Society: “CAR T-cell Therapy and Its Side Effects.”
Leukemia & Lymphoma Society: “Chimeric Antigen Receptor CAR T-Cell Therapy.”
Frontiers in Immunology: “Reactions Related to CAR-T Cell Therapy.”
MD Anderson Cancer Center: “Need CAR T Cell Therapy? Here’s What to Expect.”
American Journal of Kidney Disease: “Acute Kidney Injury and Electrolyte Abnormalities After Chimeric Antigen Receptor T-Cell (CAR-T) Therapy for Diffuse Large B-Cell Lymphoma.”
Bone & Marrow Transplantation Information Network: “Follow-Up Care After CAR T-cell Therapy.”
