Understanding CAR T-Cell Therapy and Bispecific Antibodies

Receiving a blood cancer diagnosis can feel like having to learn a new language overnight. Along with unfamiliar disease names, tests, and treatment plans, people may hear terms such as CAR T-cell therapy and bispecific antibodies. Both are forms of immunotherapy that help T cells recognize and attack cancer, but they are made and administered differently.^1-4

These treatments are not the initial therapy for many folks, and their place in care depends on individual factors such as the specific blood cancer, disease features, and previous treatment. They are approved for selected leukemias, lymphomas, multiple myeloma, and chronic lymphocytic leukemia.^2,3

Understanding these therapies can help individuals make sense of conversations with their healthcare teams.

Helping the Immune System Find Cancer

The immune system can identify and destroy abnormal cells, but cancer cells may develop ways to avoid detection or interfere with the immune response.¹ CAR T-cell therapy and many bispecific antibodies work by helping T cells recognize and attack cancer cells. The major difference is in how they accomplish that task.

What Is CAR T-Cell Therapy?

Currently approved CAR T-cell therapies are personalized cellular treatments made using a person’s own T cells, a type of white blood cell involved in immune defense.^2,3

First, blood is collected through a process called leukapheresis, which separates T cells or other white blood cells from the remaining blood components. The collected cells are sent to a laboratory, where they are genetically modified to produce chimeric antigen receptors, or CARs.^2,3 These receptors can attach to specific antigens (proteins) on cancer cells.

Before receiving the CAR T cells, people typically receive a short course of chemotherapy called lymphodepleting chemotherapy. This treatment helps prepare the body for the modified cells. When the lab has produced a sufficient quantity of CAR T cells, they are then given to the patient through a one-time intravenous infusion. Once inside the body, they continue to multiply, recognize cells carrying the target antigen, and attack them.^2,3

From cell collection to infusion, the process currently takes approximately 3 to 5 weeks, although timing may vary.² During that period, some individuals may receive “bridging therapy” to help control their cancer, although this is not needed in every case. Because of its complexity, CAR T-cell therapy is provided through specialized treatment centers with experience in cellular therapy.^2-4

CAR T-cell therapies are approved for specific forms of B-cell acute lymphoblastic leukemia, several B-cell lymphomas, multiple myeloma, and chronic lymphocytic leukemia. The exact approved use varies by product, patient age, disease subtype, and previous treatment.^2,3

What Are Bispecific Antibodies?

Bispecific antibodies are laboratory-made drugs designed to bind to two different targets at the same time. Many T-cell–engaging bispecific antibodies used for blood cancers attach to an antigen on a cancer cell with one part of the drug and to CD3, a protein on T cells, with the other. This brings the two cells close together and helps activate an immune attack.^4,5

Unlike currently approved CAR T-cell products, bispecific antibodies do not usually require collecting and modifying an individual’s cells. They are manufactured in advance and are often described as “off-the-shelf” treatments. This may allow treatment to begin more quickly than personalized CAR T-cell therapy, although evaluation, insurance authorization, and treatment-center arrangements can still take time.⁴

Bispecific antibodies are approved for several blood cancers, including certain B-cell lymphomas and multiple myeloma. Depending on the specific drug, a bispecific antibody may be given intravenously or by an injection under the skin.^4,5

Treatment with many bispecific antibodies begins with one or more smaller “step-up” doses before the full treatment dose to reduce the risk or severity of serious immune reactions. Unlike CAR T-cell therapy, which is generally given as a single infusion, bispecific antibodies are usually administered repeatedly according to a treatment schedule.^3-5

Learning how these therapies differ can help make conversations with your healthcare team feel less overwhelming, especially if these options become part of your treatment discussion.

Why Might One Be Considered Instead of the Other?

There is no single “best” option. Instead, healthcare teams consider many factors when deciding whether either treatment may be appropriate, including:

• The exact blood cancer and its biological features
• Whether the cancer expresses the treatment’s target antigen
• Which treatments have already been received
• How quickly the cancer needs to be controlled
• Overall health and organ function
• The risk of side effects
• Access to an experienced treatment center
• Individual goals and preferences

Some CAR T-cell therapies have moved into earlier lines of care for particular blood cancers. Even so, they are generally used after initial treatment has not worked, has stopped working, or is no longer considered appropriate.^2,3 Bispecific antibodies are also being studied in earlier treatment settings and in combination with other therapies.^4,5

Because approvals and recommendations continue to change, people should ask their healthcare team how a recommended therapy fits into the treatment plan for their specific diagnosis rather than relying on another person’s experience.

Understanding the Side Effects

Both treatments can cause significant side effects and require careful monitoring.

One shared risk is cytokine release syndrome, or CRS. This inflammatory reaction occurs when activated immune cells release large amounts of chemical messengers called cytokines. Symptoms may include fever, chills, fatigue, low blood pressure, a fast heartbeat, or difficulty breathing. CRS is treatable, particularly when recognized promptly, but severe cases can be life-threatening.^2-4

Neurologic complications may also occur. These can include confusion, difficulty speaking or writing, tremors, excessive sleepiness, seizures, or changes in alertness. One such complication is immune effector cell–associated neurotoxicity syndrome, or ICANS.^2-4

Other potential complications include infections, prolonged low blood-cell counts, and reduced levels of normal antibodies, sometimes called hypogammaglobulinemia.^2-4 The likelihood, timing, and severity of side effects vary by therapy. Folks should receive clear instructions about symptoms that require immediate medical attention and whom to contact after treatment.

Looking Ahead

CAR T-cell therapy and bispecific antibodies are changing the treatment landscape for several difficult-to-treat blood cancers. Although these therapies are not appropriate for everyone, they have expanded treatment possibilities for some individuals and continue to reshape how blood cancers are treated.

Learning the basic differences between these therapies can make these unfamiliar terms less intimidating and help people have more informed conversations with their hematology and oncology teams.

References

1. National Cancer Institute. Immunotherapy to treat cancer. Updated September 24, 2019. Accessed July 23, 2026. www.cancer.gov/about-cancer/treatment/types/immunotherapy
2. National Cancer Institute. CAR T cells: engineering patients’ immune cells to treat their cancers. Updated February 26, 2025. Accessed July 23, 2026. www.cancer.gov/about-cancer/treatment/research/car-t-cells
3. Brudno JN, Maus MV, Hinrichs CS. CAR T cells and T-cell therapies for cancer: a translational science review. JAMA. 2024;332:1924-1935.
4. Dima D, Banerjee R, Hansen DK. CAR T-cell therapy and bispecific antibodies in the management of multiple myeloma. Hematology Am Soc Hematol Educ Program. 2025;2025:324-333.
5. Zelenetz AD, Gordon LI, Abramson JS, et al. NCCN Guidelines insights: B-cell lymphomas 3.2025. J Natl Compr Canc Netw. 2025;23:e250048.