Menkes disease is a rare genetic condition that affects how the body absorbs and handles copper, an important mineral your body needs to function. It usually appears in the first few months of life, most often in boys. That’s because Menkes disease is linked to the X sex chromosome. More specifically, Menkes disease is caused by changes in the ATP7A gene, which helps move copper through the body.
Copper normally helps enzymes that support the growth and development of your brain, bones, liver, hair, and blood vessels. In people with Menkes disease, copper does not reach these areas in the amounts they need, while too much copper builds up in the kidneys and other areas of the body. This can lead to serious and life-threatening problems.
Baby boys with Menkes disease may have trouble growing, low body temperature, delayed development, seizures, and changes in hair and facial features. Many children do not survive past early childhood. Females may have changes in hair or skin color but often do not have serious health problems.
Early diagnosis and treatment are critical. If treatment begins before permanent brain damage occurs, some children may have better outcomes.
Because the body cannot properly absorb copper through the digestive system, treatment focuses on replacing copper so it can reach the brain and be used by cells. Zycubo (copper histidine) is a form of injectable copper that is designed to help bypass this absorption problem. It was approved by the FDA in January 2026 as the first medicine for treating Menkes Disease in children.
This article explains what to know about Zycubo for Menkes Disease.
How Do I Use Zycubo?
Zycubo is given as an injection under the skin, also called a subcutaneous injection. A health care provider should show you how to prepare and inject Zycubo before you do it for the first time. Always follow the exact instructions given by your child’s health care provider.
Zycubo comes as a powder in a vial that must be mixed before use. To mix it, you will add a sterile saline (0.9% sodium chloride for injection), then gently swirl the vial until the powder is dissolved; do not shake it. Each vial is for one-time use only, and any leftover medicine should be thrown away (do not save for future use).
After mixing Zycubo, you can inject it right away or store it for a short time. If you keep the mixed vial in the refrigerator, use it within 24 hours and let it sit at room temperature for about 30 minutes before injecting. If you keep the mixed vial at room temperature, use it within four hours. Throw away the vial if it is not used within this time.
Zycubo is injected under the skin of the stomach (at least 2 inches from the belly button), thigh, upper arm, or buttocks. Rotate injection sites each time to help reduce the risk of skin problems. Avoid injecting into areas where the skin is bruised, scarred, tender, red, discolored, or hardened. Place used needles and syringes in a sharps disposal container right away.
This is a general overview only and does not include all steps or safety details. Always read the full Instructions for Use and talk with your child’s health care provider if you have questions about preparing, storing, or injecting Zycubo. You can also call the drugmaker for support services at 888-251-2800.
How Was Zycubo Studied for Menkes Disease?
Two studies were done to evaluate how well Zycubo worked to treat Menkes disease. These studies included babies and young children who started treatment anywhere from about a few weeks old to a little over 2.5 years of age.
All children who received Zycubo were treated for up to three years. Children younger than 1 year of age received Zycubo twice a day until they reached their first birthday. Children 1 year or older received treatment once daily and could continue for up to three years.
Both studies were open-label, which means everyone knew the children were receiving Zycubo. Instead of a placebo group, researchers compared children who received Zycubo with a separate group of children with Menkes disease who did not receive copper treatment. These untreated children came from medical records collected during the same time period and were used as a comparison group.
For the main survival analysis, researchers focused on a specific group of children from both studies. This group only included children who had Menkes disease caused by certain gene changes and were born after 1999. In total, this group included 83 children. Of these, 66 children received Zycubo, and 17 children did not receive copper treatment.
These children were then divided into four groups, based on whether they received Zycubo and how early treatment or diagnosis occurred.
Two groups received Zycubo:
- The early-treatment group included 31 children who started Zycubo within the first 4 weeks of life.
- The late-treatment group included 35 children who started Zycubo after 4 weeks of age. Some children in this group did not begin treatment until several months after birth.
Two comparison groups did not receive any copper treatment:
- One untreated group included 17 children who were diagnosed around the first month of life and lived at least four weeks after diagnosis, but did not receive treatment.
- A second untreated group included 16 children who were diagnosed later, after 4 weeks of age, and lived at least two weeks after diagnosis.
By dividing children into these groups, researchers were able to compare early Zycubo treatment, later Zycubo treatment, and no treatment. The goal was to help understand how the timing of treatment affected survival in children with Menkes disease.
Most children in all groups were male. There were two females included, both in the Zycubo late-treatment group. Most children in all groups were born prematurely. More than half (63%) of the participants were White, 10% were Black or African American, 2% were Asian/Pacific Islander, and 12% identified as unknown or other races. Some (13%) were of Hispanic ethnicity.
What Were the Study Results for Early Treatment?
Researchers compared survival between children who started Zycubo early and children who did not receive copper treatment but were diagnosed early. As explained above, early treatment meant Zycubo was started within the first 4 weeks of life. The researchers also looked at median survival time. Median refers to the middle value when looking at all of the results lined up from shortest to longest survival.
Children with Menkes disease who received Zycubo treatment within 4 weeks of birth lived significantly longer than untreated children. Overall, early Zycubo treatment was linked to a 78% lower risk of death compared with no copper treatment.
In the early-treatment Zycubo group (31 children):
- 16 children (52%) were alive at the time of analysis.
- 15 children (48%) lived longer than 6 years.
- Seven children (23%) lived longer than 12 years.
- Median survival time was about 14.8 years (177.1 months).
In comparison, in the untreated early-diagnosed group (17 children):
- Two children (12%) were still alive at the time of analysis.
- No children lived longer than 6 years.
- Median survival was about 1.5 years (17.6 months).
These results show that starting Zycubo within the first 4 weeks of life was linked to longer survival in children with Menkes disease, compared with children who were diagnosed early but did not receive copper treatment. Your results may differ from what was seen in studies.
What Were the Study Results for Children Who Started Zycubo Later?
The researchers also looked at outcomes of children with Menkes disease who started Zycubo after the first 4 weeks of life. These children were compared with untreated children who were diagnosed later and did not receive copper treatment. The goal was to understand whether Zycubo improved survival even when treatment did not begin in the first month of life.
Children who started receiving Zycubo at least four weeks after birth lived significantly longer than untreated children. Overall, later treatment with Zycubo in this group was linked to a 73% lower risk of death compared with no copper treatment.
In the late-treatment Zycubo group (35 children):
- 12 children (34%) were alive at the time of analysis.
- 11 children (31.4%) lived longer than 6 years.
- One child (2.9%) lived longer than 12 years.
- Median survival time was about 5.2 years (62.4 months).
In the untreated late-diagnosis group (16 children):
- Two children (12%) were alive.
- No children lived longer than 6 years.
- Median survival was about 1.7 years (20.7 months).
These results suggest that Zycubo can help children with Menkes disease live longer, even when Zycubo is started after the first 4 weeks of life.
Keep in mind that results can vary. Talk with your child’s doctor about what to expect.
What Zycubo Side Effects Should I Be Aware Of?
Zycubo may cause side effects. Your child’s health care team will closely monitor for side effects with regular blood tests and checkups.
Zycubo contains copper, which your body needs but cannot properly handle if you have Menkes disease. Because of this, too much copper can build up in your body during treatment. Without close monitoring, this buildup can affect different organs and lead to side effects that may be serious:
- Some children using Zycubo have had kidney problems. Children with Menkes disease may already have kidney problems before starting treatment, and extra copper can make this worse. Your child’s health care provider will check kidney function with lab tests before and during treatment. Tell your health care provider right away if your child is peeing less than usual or not peeing.
- Copper buildup can also affect the liver. Blood tests will be used to monitor liver function during treatment. Report any new or worsening symptoms right away, such as yellowish eyes or skin (jaundice).
- Copper can interfere with how the body makes blood cells and uses iron. Some children developed anemia, which means low red blood cell levels. Blood counts will be checked regularly to watch for this.
Other possible Zycubo side effects and what to do about them:
- Injection site reactions: Rotate injection sites and watch for redness, swelling, or soreness. Try a cool compress to soothe the area. Call your child’s health care provider if reactions do not improve.
- Vomiting or diarrhea: Make sure your child stays well hydrated. Contact the health care provider if vomiting or diarrhea continues.
- Infections: Call the health care provider right away if your child develops fever, cough, breathing problems, or signs of infection.
Always tell your child’s health care provider about new or worsening symptoms. They can decide whether testing, monitoring, or treatment changes are needed.
Is There Any Cost Assistance Available for Zycubo?
Sentynl, the maker of Zycubo, offers a cost assistance program that may help lower the cost of treatment. Eligibility can depend on the type of insurance you have or whether you are uninsured. To see if you qualify for copay savings, visit this website. You can also call 888-251-2800 to speak with a representative about financial support options.