The short answer
CAR T-cell therapy is a type of T-cell transfer therapy that changes your own immune cells in the lab so they can better attack cancer. Your cells are collected, grown over weeks, and given back through a vein. It can cause serious side effects such as cytokine release syndrome.
T-cell transfer therapy makes your own immune cells better able to attack cancer.
The two main types are TIL therapy and CAR T-cell therapy.
Your T cells are collected, changed or selected and grown in the lab, then given back through a vein.
Growing the cells can take 2 to 8 weeks, and you may have chemotherapy first.
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The full explanation.
The simple version
CAR T-cell therapy is a type of T-cell transfer therapy. T-cell transfer therapy is a kind of immunotherapy that makes your own immune cells better able to attack cancer. It is also called adoptive cell therapy, adoptive immunotherapy, and immune cell therapy.
Instead of giving you a drug, this treatment uses your own T cells — a type of immune cell — changed or selected in a lab to fight your cancer.
CAR T-cell therapy turns your own immune cells into better cancer fighters.
The basic steps
There are two main types of T-cell transfer therapy: TIL therapy and CAR T-cell therapy. Both share the same basic steps:
- Your own immune cells are collected.
- Large numbers of these cells are grown in the lab.
- The cells are given back to you through a needle in your vein.
Growing your T cells in the lab can take 2 to 8 weeks. During this time, you may have treatment with chemotherapy and maybe radiation therapy to get rid of other immune cells. Reducing your immune cells helps the transferred T cells work better. After these treatments, the lab-grown T cells are given back to you through a vein.
TIL therapy vs. CAR T-cell therapy
TIL therapy uses T cells called tumor-infiltrating lymphocytes that are found in your tumor. Doctors test these in the lab to find out which ones best recognize your tumor cells, then treat those selected cells so they grow to large numbers quickly. The idea is that these lymphocytes have already shown they can recognize your tumor, but there may not be enough of them — so giving you large numbers can help overcome that.
CAR T-cell therapy is similar to TIL therapy, but your T cells are changed in the lab so that they make a protein called CAR before they are grown and given back. CAR stands for chimeric antigen receptor. CARs are designed to let the T cells attach to specific proteins on the surface of cancer cells, improving their ability to attack.
Which cancers are treated
A TIL therapy called lifileucel has been approved by the FDA to treat melanoma. It has also shown promise in other cancers, such as certain cervical and bile duct cancers, but for those it is still experimental.
Six CAR T-cell therapies have been approved by the FDA for blood cancers. CAR T-cell therapy has also been studied for solid tumors, including breast and brain cancers, but that use is still experimental.
Side effects to know about
T-cell transfer therapy can cause side effects that people experience in different ways. What you may have and how serious it is depends on how healthy you are before treatment, your type of cancer, how advanced it is, the type of therapy, and the dose. Doctors and nurses cannot know for sure when or if side effects will occur, so it is important to know which signs to look for.
Cytokine release syndrome. CAR T-cell therapy can cause this serious side effect. It happens when the transferred T cells, or other immune cells responding to them, release a large amount of cytokines into the blood. Cytokines are immune substances with many functions, and a sudden increase can cause fever, nausea, headache, rash, rapid heartbeat, low blood pressure, and trouble breathing. Most people have a mild form, but in some it can be severe or life-threatening.
Recognizing normal cells. Although CAR T cells are designed to recognize proteins found only on cancer cells, they can sometimes recognize normal cells too. Depending on which normal cells are affected, this can cause a range of side effects, including organ damage.
Capillary leak syndrome. TIL therapy can cause this syndrome, where fluid and proteins leak out of tiny blood vessels into surrounding tissues, causing dangerously low blood pressure. It may lead to multiple organ failure and shock.
Because serious side effects are possible, your team will monitor you closely and needs to hear about new symptoms right away.
Words to know
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Common questions
▸What is CAR T-cell therapy?
CAR T-cell therapy is a type of T-cell transfer therapy, which is a kind of immunotherapy that makes your own immune cells better able to attack cancer. In CAR T-cell therapy, your T cells are changed in the lab so they make a protein called CAR (chimeric antigen receptor) that helps them attach to and attack cancer cells.
▸How does the process work?
Both TIL and CAR T-cell therapy involve collecting your own immune cells, growing large numbers of them in the lab, and then giving them back to you through a needle in your vein. Growing the cells can take 2 to 8 weeks.
▸Why might I have chemotherapy before getting my cells back?
While your T cells are being grown in the lab, you may have chemotherapy and sometimes radiation to get rid of other immune cells. Reducing your immune cells helps the transferred T cells work better. After this, the lab-grown T cells are given back through a vein.
▸What is the difference between TIL and CAR T-cell therapy?
TIL therapy uses tumor-infiltrating lymphocytes found in your tumor; doctors select the ones that best recognize your tumor and grow them in large numbers. CAR T-cell therapy is similar, but your T cells are changed in the lab to make a CAR protein that helps them attach to specific proteins on cancer cells.
▸What cancers are treated with these therapies?
A TIL therapy has been approved to treat melanoma. Six CAR T-cell therapies have been approved for blood cancers. CAR T-cell therapy has also been studied for solid tumors such as breast and brain cancers, but that use is still experimental.
▸What serious side effects can happen?
CAR T-cell therapy can cause cytokine release syndrome, from a large release of immune substances called cytokines. Most people have a mild form, but it can be severe or life-threatening. CAR T cells can also sometimes recognize normal cells, causing side effects including organ damage. TIL therapy can cause capillary leak syndrome.
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