Your immune system guards your body like a fortress, sending protective proteins called antibodies to attack invaders like bacteria and viruses. Now, scientists and researchers have found ways to help your immune system fight a type of blood cancer called multiple myeloma.

Bispecific T-cell engagers (BiTEs) are a new type of treatments for relapsed or refractory multiple myeloma (RRMM). Here are six facts about BiTEs you should know if you or a loved one has RRMM.

1. BiTEs Help Your Immune System Fight Cancer

Monoclonal antibodies, also referred to as biologics, are human-made antibodies designed to fight disease. BiTEs are a new form of medication known as bispecific antibodies.

Our immune systems make antibodies — which are Y-shaped proteins — that attach or bind to a unique molecule of the pathogen called an antigen. The antibodies act as flags for specialized immune cells — known as T cells or T lymphocytes — to recognize and destroy the infected cells.

The prefix “bi” means “two” — and as the term “bispecific”suggests, bispecific T-cell engagers are monoclonal antibodies designed to bind to two different proteins. The first is always CD3, which is found on the outside of T cells. The second protein is found specifically on the outside of myeloma cells.

BiTEs act like bridges that connect your immune system and malignant cells. They make it easier for your immune system to destroy your cancer. Scientists are also studying BiTEs as a treatment for other blood cancers like lymphoma and leukemia.

2. BiTEs May Be an Option After Other Treatments Have Failed

The U.S. Food and Drug Administration (FDA) approved the BiTE Tecvayli, a formulation of teclistamab-cqyv, in 2022 as a therapy for RRMM in people who’ve been treated previously with three other lines of therapy. This means that they tried at least three different types of treatment, and the myeloma reappeared after each one.

Available treatment options for RRMM include:

• Immunomodulatory drugs like lenalidomide (Revlimid) and pomalidomide (Pomalyst)
• Proteasome inhibitors like bortezomib (Velcade) and carfilzomib (Kyprolis)
• Immunotherapies such as daratumumab (Darzalex) and elotuzumab (Empliciti)
• Chimeric antigen receptor T-cell therapy (or CAR T-cell therapy)

These drugs may be given alone, as single agents, or in combination regimens.

While these treatments are often effective at first, most people are eventually diagnosed with RRMM. “Relapsed myeloma” means that the cancer comes back after being destroyed in the first round of treatment. “Refractory myeloma” means that the cancer becomes resistant or stops responding to treatments.

BiTEs work differently from the common treatments. Researchers believe teclistamab-cqyv works by binding to B-cell maturation antigen (BCMA), a protein on the outside of myeloma cells. It also binds with the CD3 protein found in T cells. As a result, teclistamab-cqyv causes tumor cell lysis (destruction).

3. New BiTEs Are Being Studied in Clinical Trials

The FDA granted talquetamab a Breakthrough Therapy Designation in 2022. This designation is given to promising drugs that treat a serious or life-threatening illness.

Talquetamab is a new BiTE that’s being studied to treat adults with RRMM. Scientists and researchers have found that myeloma cells have the protein GPRC5D on their surface. Talquetamab works by binding to the CD3 protein, and in doing so, redirects T cells to mediate killing of GPRC5D-expressing myeloma cells. Healthy cells don’t have GPRC5D, so they won’t be destroyed with this treatment.

Physicians and researchers have studied talquetamab as a therapy for people with RRMM who have been treated with at least four prior lines of therapy (four different rounds of treatment).

As of July 2023, Talquetamab hasn’t been approved by the FDA yet, but clinical trials show that it may be effective.

4. BiTEs Are Given by Infusion or Injection

Like other biologics used to treat cancer, BiTEs are administered by intravenous infusions or subcutaneous (under the skin) injections. This is because if you took them by mouth, your gastric juice would split them up before they had a chance to work.

Teclistamab-cqyv is administered as a subcutaneous injection. When you first start treatment, you’ll receive increasing doses over seven days. After that, you’ll have weekly injections.

In clinical trials, IV infusions of talquetamab were given every week or every other week. Subcutaneous injections were given every week, every other week, or every month.

5. Like All Drugs, BiTE Treatment Can Have Side Effects

As with all medications, BiTEs come with potential side effects (or adverse events). They’re reported in clinical trials when BiTEs are being tested in large groups of volunteers with RRMM.

The most commonly reported side effects from teclistamab-cqyv include:

• Fever
• Fatigue
• Cytokine release syndrome (CRS), a condition caused by an overactive immune response that can present with a variety of symptoms, ranging from mild, flu-like symptoms to severe life-threatening manifestations
• Pain at the injection site
• Nausea
• Headache
• Diarrhea
• Pneumonia
• Low blood cell counts

The most common side effects of talquetamab reported in clinical trials include:

• Changes in taste
• Skin changes, such as dry or itchy skin, skin darkening, and ulcers (open sores)
• Low blood cell counts
• CRS

As you discuss treatment options for RRMM with your myeloma specialist, they’ll help you weigh the potential risks of each treatment against the potential benefits.

6. Research Shows BiTEs Are Effective for Treating RRMM

The FDA uses clinical trials for approving new drugs. These are large, well-regulated studies where physicians and researchers compare a new drug to the standard treatment. They use what’s called the overall response rate (ORR), which refers to the number of people whose cancer had a partial or total response with the treatment.

Teclistamab-cqyv was approved from clinical studies showing the ORR was 61.8 percent. This means that 61.8 percent of the study participants responded to the treatment. They also found that nine months after treatment, 66.5 percent of people were still responding.

Another study found that teclistamab-cqyv helped improve progression-free survival (PFS) and overall survival (OS) compared to standard treatments. PFS refers to how long participants live from the time they start treatment until their cancer begins progressing (growing or spreading) again. OS refers to how long participants live after starting treatment.

There currently isn’t any data available on how well talquetamab works for treating RRMM. A phase 2 clinical trial is underway to measure the ORR, PFS, and OS. It’s expected to be completed in 2026.

While there’s no cure for myeloma right now, doctors and researchers hope BiTEs like teclistamab-cqyv and talquetamab will continue to help lengthen the life expectancy of people with this type of cancer.

Read more about life expectancy with RRMM.

Talk With Others Who Understand

On MyMyelomaTeam — the social network for people with multiple myeloma and their loved ones — more than 20,000 members come together to ask questions, give advice, and share their stories with others who understand life with myeloma.

Do you have more questions about bispecific T-cell engagers for relapsed/refractory multiple myeloma? Would you consider trying a newly approved treatment for your RRMM? Share your thoughts in the comments below, or start a conversation by posting on your Activities page.