Emerging immunotherapy treatments for multiple myeloma target B-cell maturation antigen (BCMA), a protein found on the surface of cancer cells.
Multiple myeloma is a blood cancer that develops when abnormal plasma cells in your bone marrow start to divide uncontrollably. Plasma cells are a type of white blood cell and a type of B cell. In multiple myeloma, cancerous plasma cells crowd out healthy cells and produce an atypical antibody called monoclonal protein (M protein).
Over time, multiple myeloma can lead to challenges with bone marrow suppression. You may experience anemia (a low red blood cell count), easy bruising, and an increased risk of infection. M protein can build up in your body, affecting blood circulation and disrupting organ function.
After diagnosing multiple myeloma, a doctor will create an individualized treatment plan based on your age, health status, and eligibility for a stem cell transplant. Stem cell transplants are performed after high dose chemotherapy. They replenish your body with healthy cells to replace the cancerous cells.
When multiple myeloma does not respond to treatment or returns after initial treatments, doctors may recommend a BCMA-targeted therapy.
BCMA is a protein that exists on the surface of cancerous plasma cells. While it can be present on healthy cells, BCMA is found at higher levels on cancerous B cells, including multiple myeloma plasma cells.
BCMA-targeted therapies are designed to seek out BCMA on the surface of cancer cells. By targeting this specific protein site, BCMA therapies can help your immune system find and destroy cancer or deliver cytotoxic (cell-destroying) drugs directly to cancerous plasma cells.
Several types of BCMA-targeted therapies are available to treat multiple myeloma. Each works with your immune system in a different way to destroy cancer. All BCMA-targeted therapies are considered types of immunotherapy.
CAR T-cell therapy
Chimeric antigen receptor (CAR) T-cell therapy uses genetic modification to improve your T cells’ ability to detect and destroy cancer. T cells are a type of immune cell responsible for eliminating harmful cells, such as bacteria, viruses, and cancer cells.
Using a process called leukapheresis, doctors remove T cells from your blood. Healthcare professionals in a laboratory then genetically modify those cells so that they have CARs, which allow them to recognize and bind to the BCMA protein.
Once attached to the protein, T cells attack each cancerous cell and begin destroying it.
Two CAR T-cell therapies are
Bispecific T-cell engagers (BiTEs)
BiTEs also use T cells to destroy cancer cells. But unlike CAR T-cell therapy, treatment with BiTEs does not involve genetic modification.
BiTEs are drugs that help connect cancerous B cells to T cells. A BiTE drug binds to BCMA on a myeloma cell and also binds to CD3, a specific protein receptor on T cells.
Once the two cells are linked, the T cell can attack the multiple myeloma cell.
Two BCMA-targeted BiTEs are
Antibody-drug conjugates (ADCs)
ADCs use monoclonal antibodies to deliver cell-destroying drugs directly to cancer cells. Monoclonal antibodies are special molecules made in a laboratory. They act like your body’s own antibodies and seek out harmful cells for removal.
BCMA-targeted ADCs hunt down cancerous plasma cells that have the BCMA protein. Once they attach to a cell, they’re absorbed into the cell and release a cell-destroying drug.
So far, belantamab mafodotin (Blenrep) is the only BCMA-targeted ADC for multiple myeloma that has been approved by the Food and Drug Administration (FDA).
Overall, BCMA-targeted therapies for multiple myeloma have shown great effectiveness and safety, even in people who have received four or more prior multiple myeloma treatments.
According to a 2022 research review, overall response rates for BCMA-targeted therapies in multiple myeloma may be as high as 98%, depending on the individual treatment regimen and the specific BCMA therapy being studied.
Because BCMA-targeted therapy is a relatively new type of immunotherapy, no research has yet compared the effectiveness of each type of BCMA therapy with that of the others.
While BCMA-targeted therapies are effective for treating multiple myeloma, they are not yet first-line treatment options. Traditional therapies are still considered very effective, are widely available, and have extensive clinical backing.
BCMA therapies are newer and complex. They can be costly and might not be available everywhere.
Some people are not good candidates for BCMA therapy because of the risk for side effects or for other health reasons.
To find out whether BCMA-targeted therapy is right for you, you might consider asking your doctor some of these questions:
- Am I a candidate for BCMA-targeted therapy? Why or why not?
- Which type of BCMA-targeted therapy is best for me?
- Have we tried all of the first-line treatment options?
- Will using BCMA-targeted therapy affect my treatment options later on?
- How is BCMA-targeted therapy given? How often?
- What response can I expect?
- How long will this treatment take to help with my symptoms?
- Are there side effects?
- What warning signs should I watch for to know whether I’m having a reaction to the treatment?
- How long does the treatment last?
- Will the treatment affect my daily life?
It’s always OK to bring someone with you to your appointments to take notes or provide an outside perspective. To make the most of your time, consider writing down your questions and concerns before your appointment.
Multiple myeloma is a blood cancer that begins in plasma cells, which are a type of B cells. While chemotherapy and stem cell transplants are the traditional first-line treatments for multiple myeloma, doctors may also recommend immunotherapies.
BCMA-targeted therapies are immunotherapies that can help your immune system fight cancer cells. Some, such as ADCs, deliver cell-destroying drugs directly to multiple myeloma cells. Doctors currently use this treatment when multiple myeloma does not respond well to typical treatment or comes back after treatment.