Juvenile myelomonocytic leukemia (JMML) treatment

Before a child begins treatment for juvenile myelomonocytic leukemia (JMML), the parents or caregivers, the child (if appropriate), and the doctor should discuss treatment options, one of which may be a clinical trial. Like all treatment options, clinical trials have possible risks and benefits. By considering all treatment options, including clinical trials, parents will be taking an active role in a very important decision.  

Parents are advised to seek treatment from a pediatric hematologist-oncologist who is experienced in treating JMML. 

Learn more about communicating with your blood cancer specialist or find a list of suggested questions to ask your healthcare providers.  

Types of treatment for JMML 

Without treatment, JMML progresses rapidly. There are two widely used JMML treatment protocols: stem cell transplantation and drug therapy. 

Transplantation is recommended for all children with NF1, somatic PTPN11 and KRAS mutations. For some patients with an NRAS mutation, treatment with azacitidine instead of a stem cell transplant may be considered. A “watch-and-wait” approach can be adopted in children with germline CBL mutations and PTPN11-mutated Noonan syndrome. 

Learn more about watch and wait. 

Stem cell transplantation 

Allogeneic stem cell transplantation is the only potentially curative treatment option for JMML. Although this treatment has been noted to achieve long-term remission in up to 50 percent of patients, relapses occur in up to 35 percent to 40 percent of patients after transplantation, often within the first year. While the rates of relapse are high, patients may achieve a cure with a second stem cell transplant. 

Standard chemotherapy before a stem cell transplant is often undertaken to control the disease during the one- to two-month period that is required to arrange a stem cell transplant. Occasionally, pre-transplant chemotherapy can also result in a temporary remission going into the transplant, which may be associated with improved long-term outcomes. 

Learn more about stem cell transplantation.  

Drug therapy 

Azacitidine (Vidaza®) is approved by the FDA to treat pediatric patients aged 1 month and older with newly diagnosed JMML. 

Using chemotherapy alone will almost always lead to the disease coming back after the treatment is over. 

Learn more about drug therapy.  For information about the drugs listed on this page, visit our cancer drug listing.

Clinical trials  

Since JMML is difficult to treat with currently available drug therapy, participating in a clinical trial investigating new drugs may be a good treatment choice for your child, even right after diagnosis. Clinical trials are underway to help extend survival and increase the quality of life for juvenile myelomonocytic leukemia (JMML) patients. Today's standard treatments for cancer are based on earlier clinical trials. LLS continues to invest funds in JMML research.  

Clinical trials can involve new drugs, new combinations of drugs, or previously approved drugs being studied in new ways such as new drug doses or new schedules to administer the drugs. Clinical trials are conducted worldwide under rigorous guidelines to help doctors find out whether new cancer treatments are safe and effective or better than the standard treatment. 

Learn more about clinical trials.   

Get free clinical trial support! Visit our Clinical Trial Support Center (CTSC).

Connect with registered nurses with expertise in blood cancers who can personally assist you or your caregiver through each step of the clinical trial process. 

 JMML treatment side effects 

Although individuals with JMML have too many white blood cells, these cells do not function normally and affected children may develop recurrent infections such as bronchitis and tonsillitis. Decreased appetite, poor weight gain, irritability, and failure to thrive may also occur in children with JMML. 

The following side effects are common to JMML treatment: 

• Nausea and vomiting
• Diarrhea
• Mouth sores
• Infections
• Slow growth rate
• Hair loss
• Low levels of red blood cells, white blood cells, and platelets in the blood
• Congestive heart failure
• Graft-versus-host disease (if your child has undergone allogeneic stem cell transplantation) 

Learn more about JMML treatment side effects and how to manage them.  

Treatment results 

Parents of JMML patients are advised to discuss survival information with their child’s pediatric hematologist-oncologist. Keep in mind that outcome data can show how other children with JMML responded to treatment, but it cannot predict how any one child will respond.

Outcomes for JMML patients are variable. Some patients have rapidly progressing disease while others have a relatively slow-growing course. To date, the only potentially curative therapy is allogeneic stem cell transplantation. The median survival time for patients who have aggressive JMML and who do not receive a transplant can be as short as 10 to 12 months and, on average, is less than 2 years. 

There are individual factors that influence patient outcomes. Factors that may indicate a less favorable outcome include: 

• Age greater than 2 years
• A low platelet count at diagnosis
• Elevated hemoglobin F levels
• More than one gene mutation detected in JMML cells at diagnosis

In contrast, in a small percentage of patients the disease resolves spontaneously, without the need for treatment. Spontaneous improvement of some JMML patients with somatic NRAS mutations and germline CBL mutations has been noted. 

Follow-up care 

Find more information about follow-up care, including what to expect, long-term and late effects of treatment, survivorship clinics, and other resources such as The National Comprehensive Cancer Network (NCCN) treatment guidelines.

Parents of JMML patients are advised to discuss survival information with their child's doctor. The treatment of JMML patients hasn't led to long-lasting remissions in most cases. However, individual factors influence patient outcomes.   

After Diagnosis: Navigating Your Child's Care 

Navigating your child’s blood cancer care isn’t always simple or straightforward—but we’re here to guide you through it. Whether they’re newly diagnosed or in remission, you’ll find the information, support, and resources you need to navigate every step of your child’s blood cancer journey. 

Visit Navigating Your Care: Children and Teens