How Treatment Works for CAR T-Cell Therapy Patients

CAR T-cell therapy is a form of immunotherapy that uses specially modified T cells – part of the body’s defense system against disease – to attack cancer.

As of March 2021, CAR T-cell therapy has been approved by the U.S. Food and Drug Administration as standard therapy for:

  • Some adult patients with aggressive non-Hodgkin lymphoma that has relapsed after prior treatments, or has not responded to other therapies (refractory).
  • Some patients with relapsed or refractory mantle cell lymphoma.
  • Some patients with relapsed/refractory follicular lymphoma.
  • Patients with relapsed/refractory multiple myeloma.
  • Patients age 25 and under with relapsed or refractory B-cell acute lymphoblastic leukemia.

The treatment process entails a standard series of steps.


Patients undergo a number of tests and screenings to determine if CAR T-cell therapy is appropriate for them.


T cells are collected from patients via apheresis, a process in which blood passes through a machine that separates out T cells and returns the remaining blood to the patient.

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The T cells are sent to a laboratory where they are genetically engineered to produce chimeric antigen receptors (CARs) on their surface. CARs are proteins that allow the T cells to recognize proteins called antigens on the surface of targeted tumor cells.


The genetically modified T cells are grown in a laboratory until there are millions of them, which can take a few weeks. When there are enough CAR T cells, they are frozen and sent to the hospital or center where the patient is being treated.

Conditioning therapy

Caron Jacobson, MD, medical director of Dana-Farber’s Immune Effector Cell Therapy Program.
Caron Jacobson, MD, medical director of Dana-Farber’s Immune Effector Cell Therapy Program.

Prior to receiving an infusion of the CAR T cells, patients may receive chemotherapy for their cancer. This helps to create space for the infused CAR T cells to expand and proliferate in the body.


Soon after chemotherapy, patients are admitted to the hospital and the CAR T cells are re-infused in a process similar to a blood transfusion. This is a one-time procedure, although patients may remain in the hospital for several weeks to monitor their response to the treatment, overall condition, and side effects.


The recovery period for CAR T-cell therapy lasts approximately two to three months. After receiving their infusion of CAR T cells, patients remain in the hospital for one to three weeks so clinicians can monitor their response to the therapy and manage any side effects.

Although the type and severity of side effects vary from patient to patient, there is a significant risk that complications will occur within a few weeks of treatment. Most often, these complications are temporary and subside on their own or with treatment. Possible side effects include cytokine release syndrome, an inflammatory condition with flu-like symptoms such as high fever and/or chills, but can include low blood pressure and difficulty breathing as well as other organ dysfunction; and neurologic difficulties such as confusion, difficulty understanding language and speaking, or stupor.

After their release from the hospital, patients have periodic follow-up appointments over the next few months to be evaluated for side effects and response to the therapy. It is possible but uncommon for patients to be re-admitted to the hospital during this period with recurrent side effects.

Evaluations for how well patients respond to therapy vary with the type of cancer being treated. Patients with B-ALL have a bone marrow biopsy done a month after CAR T-cell infusion. Patients with B-cell non-Hodgkin lymphoma have a PET scan one month after treatment. Patients are seen by their physician every one to three months for the next several years, during which time they are monitored for disease relapse with blood tests, physical exams, and/or bone marrow biopsies and PET or CT scans.

Because each patient is different, patients should talk with their physician about each aspect of their treatment and raise any concerns they may have.

Learn more about CAR T-cell therapy from the Cellular Therapies Program at Dana-Farber Cancer Institute.