Maintenance Therapy for Multiple Myeloma
- Maintenance therapy for multiple myeloma is designed to keep the disease in remission for as long as possible before a relapse occurs.
- The main drug used in maintenance therapy is an immodulatory agent called lenalidomide (Revlimid), but other medications have been approved or are in the pipeline.
- Maintenance therapy carries substantial benefits, but also some potentially serious risks and uncomfortable side effects, so a thorough conversation with your doctor at the outset is critical.
The goal of maintenance therapy is to prolong the remission phase before someone has to go through multi-drug rounds of chemotherapy, explains hematologist Dr. Matthew Pianko, a multiple myeloma specialist with the Rogel Cancer Center at the University of Michigan in Ann Arbor.
Read MoreMaintenance Therapy Medications
The primary medication used in maintenance therapy for multiple myeloma is the oral immodulatory agent lenalidomide (Revlimid). The drug helps the immune system identify and destroy myeloma cells and affects the blood vessels cancer cells rely on for growth. Lenalidomide starves myeloma cells of blood. Dr. Pianko says that the drug is usually taken daily for periods of three out of four weeks, though there is no standard time frame for optimal maintenance. He adds that this type of maintenance therapy is similar to the approach taken in managing other chronic diseases, such as diabetes and high blood pressure.A meta-analysis of three large randomized clinical trials of people who had stem cell transplants for multiple myeloma found that the median progression-free survival (PFS) of those taking lenalidomide was 52.8 months. The research, published in the October 2017 Journal of Clinical Oncology, also found that at the median follow-up time of 79.5 months the median overall survival (OS) benefit had not yet been reached in the group of study participants taking lenalidomide. The median OS for the group taking a placebo was 86 months.
A separate study of people with multiple myeloma who were not eligible for transplants compared maintenance therapy using lenalidomide and the corticosteroid dexamethasone with therapy involving the medications melphalan, prednisone, and thalidomide (MPT). In the study, published in the November 2017 journal Blood, the median PFS and the median OS were both significantly longer among the individuals taking lenalidomide and dexamethasone compared with the MPT group.
Corticosteroids help reduce inflammation and may also help reduce nausea and other chemotherapy side effects. However, dexamethasone, prednisone and other corticosteroids can also suppress the immune system over time, raising the risk of serious infections. The primary risks associated with lenalidomide are lower levels of platelets and white blood cells. The drug also carries a risk of nerve damage.
Another medication, called bortezomib (Velcade), is also sometimes used in maintenance therapy for multiple myeloma. The drug is a proteasome inhibitor, which means it blocks the action of proteasomes cellular complexes that break down proteins. Bortezomib is used to treat both multiple myeloma and mantle cell lymphoma. The drug has also been shown to provide special benefit for high-risk individuals with kidney problems.
Research is currently underway to determine if certain monoclonal antibody medications may be effective in maintenance therapy. One drug in particular, daratumumab (Darzalex) is being investigated in clinical trials. A similar monoclonal antibody called isatuximab-irfc (Sarclisa) earned FDA approval to treat relapsed refractory multiple myeloma.
Takeaway
Though most people on maintenance therapy for multiple myeloma will relapse eventually, it can extend PFS and OS in many cases. And along with the sustained suppression of myeloma there are additional benefits of maintenance therapy. These include the possible prevention of additional genetic mutations and the possible elimination of minimal residual disease.
Potential risks of maintenance therapy include treatment-related toxicity and treatment fatigue. Dr. Pianko adds that lenalidomide can also lead to poor absorption of bile acid in the small intestine, resulting in loose stools. "We have been successful in treating Revlimid-related diarrhea using some cholesterol medications, which soak up these extra bile acids and can lead to a more tolerable regimen," he says.
To better understand how the risks and benefits of maintenance therapy may affect you, talk with your doctor. If you are currently on maintenance therapy and are experiencing medication side effects or other problems, talk with your doctor. You may be able to take a lower dose or change medications and achieve the desired outcomes. And the longer you can go without a relapse, the greater the chances that new therapies may come along that will further preserve your health and well-being.
"In general, our goal is to minimize the amount of side effects that patients have during maintenance therapy to try to maximize their quality of life, while still trying to keep the disease under control," Dr. Pianko says.
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