Approved Treatments for Myeloma
Myeloma is a type of cancer that affects immune cells called B-cells. Although no cure is currently available for myeloma, several treatments can help reduce B-cell proliferation and minimize the severity of symptoms.
Most therapeutic strategies for myeloma involve using a combination of the treatments below.
Chemotherapy agents are medications that stop the growth of cancer cells by either killing them or inhibiting their division. Most chemotherapy agents target rapidly dividing cancer cells, although they often affect healthy cells as well. These therapies can be given as a monotherapy (single medication) but are often given in combination with treatments like steroids, or targeted therapies such as proteasome inhibitors.
Bendamustine is a purine analog that is used in combination with a corticosteroid called prednisone to treat newly diagnosed multiple myeloma patients. Bendamustine also works as an alkylating agent to prevent DNA from replicating, which results in cell death. It is approved in Europe to treat multiple myeloma but not the U.S.
Cisplatin is a platinum-containing chemotherapy agent used alone or in combination with other medications to treat a variety of cancers, including multiple myeloma. Cisplatin binds to DNA and prevents its repair, eventually leading to cell death. The activity of cisplatin is further enhanced by the use of other chemotherapy agents, such as etoposide.
Cyclophosphamide is an alkylating agent that affects DNA replication, preventing cell division. The activation of the treatment happens in the liver, where it is converted into an active form called aldophosphamide. Cyclophosphamide is often used in combination with Velcade (bortezomib) or dexamethasone as a first-line treatment for multiple myeloma.
Cytarabine, also known as cytosine arabinoside, is an antimetabolite chemotherapy agent that works by killing cells in which DNA is being actively synthesized. The active form of the therapy is incorporated into the DNA, where it blocks the synthesis of new DNA, halting cell division. Blocking cell division stops cancer from spreading and makes cancerous cells more vulnerable to other chemotherapy agents.
Doxorubicin is an anthracycline commonly used to treat many types of cancers, including multiple myeloma. It is thought to work by binding to an enzyme called topoisomerase 2, which is involved in DNA replication, and blocking its activity, leading to cell death. Doxorubicin treatment may also increase the production of ceramides, a type of fat inside the cells, which prevents cell division through a series of downstream events.
Etoposide is used in the treatment of many cancers including multiple myeloma. It is derived from a toxin present in the Mayapple plant. It binds to and blocks the activity of an enzyme called topoisomerase 2. By binding to topoisomerase 2 and blocking its activity, etoposide causes the enzyme not to be able to rejoin the cuts in the DNA, which leads to DNA damage and cell death.
Idarubicin is an anthracycline used to treat several cancers, such as acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), metastatic breast cancer, and multiple myeloma. Idarubicin attaches to DNA to inhibit the activity of topoisomerase 2, preventing the attachment of DNA fragments during replication. This arrests cell division and causes cell death.
Melphalan is an alkylating agent used as palliative chemotherapy for symptom relief in multiple myeloma patients. At higher doses, it is also used as a standard conditioning regimen prior to an autologous hematopoietic stem cell transplant (AHSCT). At these doses, melphalan is more potent against myeloma cells, but also drastically reduces the number of healthy blood-forming cells in the bone marrow.
Immunomodulatory treatments work through several mechanisms such as boosting the function of immune cells called T-cells and natural killer (NK) cells, suppressing angiogenesis — the formation of new blood vessels — to cut off the nutrient supply to the tumor, and decreasing the production of cell-signaling molecules. Immunomodulatory treatments are usually prescribed in combination with other treatments, such as steroids and proteasome inhibitors.
Pomalyst (pomalidomide) is an oral immunomodulatory treatment used to treat multiple myeloma patients whose disease has relapsed or is not responsive to other treatments. Pomalyst has several mechanisms of action, including inhibiting the growth and survival of treatment-resistant myeloma cells and improving normal immune function
Revlimid (lenalidomide) is an oral therapy developed for multiple myeloma, myelodysplastic syndromes, and mantle cell lymphoma. Revlimid in combination with dexamethasone is approved for multiple myeloma patients who have had at least one prior treatment. It also can be used to treat patients who are not eligible for AHSCT and as a maintenance therapy for those who have undergone AHSCT.
Thalomid (thalidomide) is the synthetic derivative of the amino acid glutamic acid. First-in-class derivatives of thalidomide such as Revlimid and Pomalyst are now preferred over Thalomid because of better efficacy and lower side effects. Thalomid, however, is a good alternative to Revlimid for myeloma patients with low blood cell counts.
Proteasome inhibitors work by targeting the protein breakdown and recycling machinery of the cell called the proteasome. Proteasomes are protein complexes in the cell that are responsible for breaking down proteins and recycling their components. Because cancer cells divide so quickly and produce so much protein, proteasomes have to work overtime to keep the cell functioning.
Proteasome inhibitors target cancer cells by blocking the breakdown of proteins by the proteasome. Without functioning proteasomes, waste proteins build up within these cells, poisoning them and causing them to die.
Kyprolis (carfilzomib) is an infusion treatment approved to treat refractory myeloma — that which has not responded to two or more other treatments. It contains a small molecule called carfilzomib, which binds irreversibly to proteasomes, preventing them from breaking down proteins. This causes proteins to build up inside cells, poisoning them. Fast-growing cells like myeloma cells are more prone to the effects of carfilzomib.
Ninlaro is an oral medication used to treat myeloma in combination with Revlimid (lenalidomide) and dexamethasone in patients who have received at least one prior treatment. The inhibition of proteasomes using treatments such as Ninlaro ensures that cells cannot repair damaged proteins. Protein damage is often the result of aggressive cell division in cancer cells. That then results in their accumulation, causing the death of cancer cells.
Velcade (bortezomib) is the first-line treatment for multiple myeloma and mantle cell lymphoma. It is an intravenous injection that includes a small molecule that inhibits the activity of the 26S proteasomes, which are large protein complexes that degrade or break down proteins that are marked by the body’s cellular machinery for destruction. Inhibiting the function of the 26S proteasomes is toxic for cells and leads to their death.
CD38 inhibitors are a class of medication that target the CD38 protein, which is found abundantly on the surface of myeloma cells. The binding of the medicines to the CD38 protein results in the inhibition of tumor growth and induces cell death.
Histone deacetylase (HDAC) inhibitors are anti-cancer agents that work by inhibiting the activity of the HDAC enzyme. HDACs remove acetyl groups from a class of protein called histones and alter the interaction between histones and DNA. Inhibiting the activity of HDAC helps turn on tumor suppressor genes and control cell division.
Inhibitors of nuclear export are compounds that bind to a protein called XPO1 (exportin 1) and block its activity. This results in tumor suppressor genes remaining within the nucleus and stopping cell growth.
Darzalex (daratumumab) is a laboratory-made antibody that targets the CD38 protein. It is approved to treat newly diagnosed, and relapsed and/or refractory myeloma patients, either alone or in combination with other approved treatments. It is available as an intravenous (into-the-vein) infusion and as a subcutaneous (under-the-skin) injection formulation.
Farydak (panobinostat) is an oral HDAC inhibitor approved to treat relapsed or refractory myeloma patients who have already been treated with Velcade and an immunomodulatory treatment such as Revlimid or Thalomid. By inhibiting HDACs, Farydak is thought to interfere with the ability of myeloma cells to multiply and remove waste proteins, resulting in the inhibition of cancer cell growth.
Sarclisa (isatuximab) is a monoclonal antibody therapy that targets the CD38 protein and promotes its death. It is approved for use in combination with Pomalyst and dexamethasone to treat adults with myeloma who failed at least two prior lines of therapy, including Revlimid and a proteasome inhibitor, and experienced disease progression on the most recent therapy. It is administered via intravenous infusion.
Xpovio (selinexor) is an oral treatment, used in combination with dexamethasone, for people with relapsed or refractory multiple myeloma treated with at least four prior therapies and who are not responding to several types of these therapies. Xpovio inhibits the activity of XPO1, blocking nuclear export to prevent the loss of tumor suppressors within cancer cells.
Other approved treatments for myeloma include SLAMF7 regulators, stem cell transplants, and human monoclonal antibodies.
Empliciti (elotuzumab) is a humanized monoclonal antibody used in combination with Revlimid and dexamethasone, and with Pomalyst and dexamethasone for the treatment of relapsed and refractory multiple myeloma patients who have undergone two or three previous therapies. It is an intravenous injection that works by binding to SLAMF7 on myeloma cells, rendering them vulnerable to recognition and killing by NK cells, and by activating NK cells and other immune cells that produce SLAMF7.
Autologous hematopoietic stem cell transplant (AHSCT) is the process of transplanting hematopoietic stem cells — cells in the bone marrow from which all kinds of blood cells, such as red blood cells, white blood cells, and platelets originate — into patients, so their body can create new and healthy blood cells to compensate for their loss in diseases such as multiple myeloma. The term “autologous” indicates that these cells are harvested from a patient instead of a donor.
Xvega (denosumab) is an antibody approved to treat bone problems in multiple myeloma patients. It binds to and blocks the activity of bone cells called osteoclasts, which play a role in breaking down bone tissue and are overactive in multiple myeloma. Specifically, it works by blocking the activity of the RANK ligand, a protein essential for osteoclast formation, function, and survival, to protect patients’ bones.