Multiple myeloma is not considered curable. However, with recent advances in treatment, it can be managed like a chronic disease in some people.
The mainstays of treatment for multiple myeloma have been chemotherapy followed by stem cell transplant for people healthy enough to tolerate the procedure. Targeted therapies and immunotherapies have also been used, either to prepare people for a stem cell transplant or in place of one. Recent advances in immunotherapy have changed the way many people are treated, especially those unable to have a stem cell transplant.
Immunotherapy
Immunotherapy is treatment that helps the body’s immune system fight cancer more effectively. Types of immunotherapies being used or tested for multiple myeloma include:
CAR T Cells
CAR T cells are an immunotherapy in which a patient’s T cells, a type of immune cell, are changed in the lab so they will better attack cancer cells and then returned to the patient’s bloodstream.
Two types of CAR T cells have been approved by the FDA to treat multiple myeloma that has come back after previous treatments:
Researchers are now testing whether some patients may benefit from getting CAR T-cell therapy instead of a stem cell transplant as their initial treatment.
Currently, CAR T cells must be created from scratch for each patient, making them the most personalized of therapies. But this process is complicated and expensive. Researchers have been testing the use of so-called off-the-shelf CAR T-cell therapies, which could potentially be made in bulk and used immediately.
An ongoing trial at NCI is also testing another type of immunotherapy using T cells, called TCR T-cell therapy, in people with multiple myeloma who have at least one tumor that can be removed surgically.
Bispecific T-Cell Engagers (BiTEs)
BiTEs are drugs that latch onto both tumor cells and T cells. By bringing T cells and cancer cells close together, they help the T cells recognize and destroy the cancer cells.
Three BiTEs have been approved by the FDA to treat adults with multiple myeloma that came back or did not get better after treatment with several other anticancer therapies:
Researchers are now studying whether giving these drugs to people with multiple myeloma who have received only one previous treatment can help keep the disease at bay for longer. They’re also making sure the potential side effects, such as an increased risk of dangerous infections, don’t outweigh the potential benefits.
Ongoing trials are also testing whether using more than one BiTE at the same time can keep multiple myeloma in remission for longer than using a single BiTE. Additional trials, including one sponsored by NCI, are investigating combinations of other new myeloma therapies with BiTEs.
Immunomodulating Drugs
Immunomodulating agents are drugs that either stimulate or suppress parts of the immune system to help the body fight cancer. These types of drugs, including lenalidomide (Revlimid) and pomalidomide (Actimid), have been used for decades to treat some people with multiple myeloma.
Studies are now testing a new generation of immunomodulating drugs that have been developed for use once resistance to current drugs occurs. These include iberdomide and mezigdomide.
Targeted Therapies
Targeted therapy treats cancer by shutting down proteins that control how cancer cells grow, divide, and spread. Some of the earliest targeted therapies, drugs called proteasome inhibitors, were developed for use in multiple myeloma. These drugs, such as bortezomib (Velcade), block the action of proteasomes, large protein complexes that help destroy other cellular proteins when they are no longer needed.
But resistance to proteasome inhibitors eventually develops and multiple myeloma starts to grow again. So researchers are searching for new ways to shut down multiple myeloma cells using targeted drugs.
Approaches being tested include:
Picking very specific populations for treatment. For example, studies found that adding venetoclax (Venclexta)—a drug that has shown promise in treating some types of leukemia—to other multiple myeloma drugs actually made myeloma grow faster. However, further research suggested that people whose multiple myeloma tumors harbor a rare genetic mutation may benefit from venetoclax. Clinical trials are now testing the drug only in people with this specific gene change.
Targeting a family of genes called RAS. After pancreatic cancer and colorectal cancer, multiple myeloma is the third most likely cancer type to be driven by changes in RAS. RAS used to be considered “undruggable,” that is, that it couldn’t be shut down with targeted therapies. But over the last decade, drugs have been developed that can shut down RAS and stop tumor growth. Clinical trials, including one at NCI, are now testing such drugs in people with multiple myeloma.
Targeting epigenetic regulation of cancer cells. Epigenetics refers to changes in the way genes are switched on and off that don’t involve changes in the actual DNA sequence. Drugs that shut down cancer cells by targeting their epigenetic regulation are now being tested in multiple myeloma.
Monoclonal antibodies (Mabs). Mabs are versions of immune system proteins that are created in the lab and bind to cancer cells. They can kill cancer cells directly or indirectly, by engaging the immune system to kill the cancer cells.
A Mab called daratumumab (Darzalex) binds to a protein found on the surface of myeloma cells and helps immune cells kill myeloma cells. Daratumumab is FDA approved to be used with some drug combinations for newly diagnosed multiple myeloma, as well as myeloma that has relapsed, and is being tested in addition to other combinations.
For example, a recent study tested adding daratumumab to the standard chemotherapy drugs given after an initial diagnosis of multiple myeloma. Patients treated with daratumumab lived substantially longer without their cancer getting worse or dying than those who received the standard treatment only. An ongoing study is now testing whether giving people with newly diagnosed multiple myeloma a treatment regimen that includes daratumumab can lengthen the time before a stem cell transplant is needed.
FDA has also approved another Mab, called isatuximab (Sarclisa), to be given along with the drugs bortezomib (Velcade), lenalidomide (Revlimid), and dexamethasone. The approval was based on a clinical trial called IMROZ, which showed that the four-drug regimen substantially increased the time patients lived without evidence of their cancer coming back or getting worse.
Elotuzumab (Empliciti) is another monoclonal antibody approved by for myeloma that has relapsed after previous treatment. This Mab targets a different protein on myeloma cells than the one targeted by daratumumab and isatuximab, so it may be effective after other antibodies stop working. Elotuzumab is currently being tested in combinations with other targeted therapies and with immunotherapies.
Advances in Stem Cell Transplant
Despite advances in immunotherapy and targeted therapies, autologous stem cell transplant is still used to treat many people with multiple myeloma. But often, too few stem cells can be successfully collected from a patient, making transplant impossible. Researchers are working to make stem cell transplant an option for more people with this cancer type.
For example, a clinical trial funded in part by NCI tested the injection of a drug called motixafortide (Aphexda) in addition to injections of G-CSF, the drug most widely used to “mobilize” stem cells from the bone marrow to the blood. People who received motixafortide had a markedly increased number of stem cells that could be collected for transplant compared with people who received G-CSF alone. Motixafortide received FDA approval in 2023 for use as part of preparation for an autologous stem cell transplant.
