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Updated on February 26, 2025
Myelodysplastic syndromes (MDS) are a group of cancers where the bone marrow produces abnormal, immature blood cells that have a shortened lifespan. This can cause a person to have lower-than-normal amounts of healthy blood cells. This can lead to problems related to low amounts of healthy blood cells, including anemia, easy or excessive bleeding and bruising, and frequent infections.
MDS can also progress into acute myeloid leukemia (AML), a type of fast-growing blood cancer that produces large amounts of cancerous white blood cells.
Hypomethylating agents (HMAs) are a type of chemotherapy drug that are often used in the treatment of myelodysplastic syndromes (MDS), including lower-risk MDS and higher-risk MDS. HMAs are also used in the treatment of AML.
If you or a loved one is living with MDS, it’s likely that you will discuss this treatment with a healthcare team at some point. Here are a few things to know.
What is a hypomethylating agent?
To understand what an HMA is and how it works, it helps to review the basics of chemotherapy.
How does chemotherapy work?
Chemotherapy refers to a category of anti-cancer drugs. There are many different types, which work in different ways. But the basic idea is that chemotherapy drugs contain chemicals that disrupt a specific phase in the lifecycle of a cell. Because cancer cells divide and grow more quickly than normal, healthy cells, chemotherapy drugs are often effective at destroying cancer cells.
How do hypomethylating agents work?
HMAs act on a DNA methylation, a process where chemicals called methyl groups get added or removed from DNA. These chemicals do not change the structure of that DNA but do change how specific genes (sections of DNA) function, and what proteins get made or do not get made.
For example, this process can shut off tumor suppressor genes—genes that control the production of proteins that regulate the lifecycle of a cell. When a tumor suppressor gene is shut off, cells can grow and divide in an uncontrolled way. This can contribute to the formation and spread of cancer cells.
HMAs counteract DNA methylation. This can kill cancer cells. These drugs may also help the bone marrow produce healthy blood cells.
How are HMAs administered?
There are several types of HMAs that are used in the treatment of MDS, which are administered in different ways. Depending on the drug prescribed, a person may receive an intravenous infusion (into a vein), a subcutaneous infusion (under the skin), or take an oral medication.
HMAs are typically given in treatment cycles—a period where a person is receiving a treatment, followed by a period of rest where a person is not receiving treatment. The number of cycles will vary from person to person.
Can HMAs cause side effects?
All cancer therapies cause side effects, and side effects—including the possibility of severe side effects—are an important topic to discuss with a healthcare provider before starting any treatment. In addition to killing cancer cells, HMAs also cause damage to healthy tissues.
Side effects of HMAs can include:
- A drop in blood cell numbers that usually improves with time.
- Fatigue, nausea, fever, and GI symptoms (such as vomiting, diarrhea, or constipation). These side effects are typically milder than the side effects caused by other types of chemotherapy.
- Infusion site reactions (with subcutaneous injections).
Your healthcare provider can answer questions on side effects and how side effects can be managed.
What are the other treatment options?
No cancer treatment is right for every person. While HMAs are a commonly used treatment option for MDS, other treatment options may be recommended. Other treatment options can include:
- Therapies to improve blood cell counts, such as blood transfusions, platelet transfusions, growth factor medicines, and other drugs that increase blood cell production.
- Drugs that modify or suppress the immune system.
- Targeted therapy drugs, which can work if cancer cells have specific mutations.
- Stem cell transplantation (bone marrow transplant). This has the potential to cure MDS but carries a risk of life-threatening complications. This is only recommended for certain cases of high-risk MDS.
- More intensive chemotherapy treatment may be recommended if there is a high risk of MDS progressing into acute myeloid leukemia.
Age, overall health, medical history, and personal preferences are important factors when making treatment decisions about MDS. Talk to your healthcare providers about your treatment options, what you need from treatment, and what they recommend.
