Zycubo (copper histidinate)
An approved treatment for Menkes Disease.
The same compound appears under different names depending on the context. Here is how to identify Copper histidinate wherever you encounter it, plus the key facts at a glance.
- Generic name
- Copper histidinate
- Brand name
- Zycubo
- Development code
- CUTX-101
- Drug class
- Copper replacement (trace element therapy)
- Manufacturer
- Sentynl Therapeutics
- How it's taken
- Given as a subcutaneous injection (under the skin).
The first and only FDA-approved treatment for Menkes disease. Copper histidinate bypasses the defective ATP7A copper transporter to deliver copper directly into the bloodstream, dramatically improving survival when treatment begins in the first weeks of life.
Where Copper histidinate fits
The only FDA-approved treatment for Menkes disease. Transforms a disease with 95% mortality by age 3 into a potentially treatable condition when diagnosed and treated within the first weeks of life. Gene therapy approaches targeting ATP7A are in early development at the NIH but remain years from clinical availability.
How Copper histidinate works
In Menkes disease, a genetic defect in the ATP7A gene prevents copper absorbed from food from being transported out of intestinal cells and into the bloodstream. This creates a paradox: copper accumulates uselessly in the gut while the brain, bones, and other organs starve for it. Copper is essential for enzymes that build brain connections, produce energy in cells, create connective tissue, and synthesize neurotransmitters.
Copper histidinate works by providing copper in a form (bound to the amino acid histidine) that can enter the bloodstream through subcutaneous injection, completely bypassing the broken intestinal transport system. Once in the blood, copper-histidine complexes are taken up by cells and used to activate the copper-dependent enzymes that Menkes patients lack.
Timing is everything. In the pivotal NIH study, babies who received copper histidinate early in life had median survival of 14.8 years, compared to about 1.5 years (17.6 months) in an untreated comparison group. The treatment must begin before irreversible brain damage occurs, ideally within the first weeks of life, making early diagnosis critical.
Mechanism: Copper replacement therapy that bypasses the defective ATP7A transporter, delivering bioavailable copper directly to the bloodstream to restore activity of copper-dependent enzymes critical for brain development
Side effects and safety
The label warns that extra copper can build up and may cause kidney injury, liver problems, and blood abnormalities such as anemia. Blood tests (copper, ceruloplasmin, electrolytes, kidney and liver function, and blood counts) are needed before starting, every 6 weeks for the first 6 months, every 3 months for the next 18 months, and every 6 months after that. The most common side effects in studies included infections such as pneumonia, breathing problems including respiratory failure, seizures, vomiting, fever, anemia, and injection site reactions. Because the studies had no comparison group, it is hard to tell which of these were caused by the medicine and which by Menkes disease itself. Because Menkes disease involves progressive neurological decline regardless of treatment timing, distinguishing drug effects from disease effects requires careful clinical monitoring.
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Copper histidinate
Given as a subcutaneous injection (under the skin). Zycubo is FDA-approved for children (pediatric patients) with Menkes disease. It is not approved for occipital horn syndrome (OHS). For infants under 1 year, the dose is 1.45 mg twice daily. For patients aged 1 to 17, the dose is 1.45 mg once daily. Treatment should begin as early as possible after diagnosis, ideally within the first weeks of life, and continues through childhood.
Availability and cost
Only available as the brand-name product.
Help paying for Zycubo
Pick your insurance to see which help fits. Drugmaker copay cards can't be used with Medicare, Medicaid or TRICARE; charity funds are the usual route there.
- Insurance and case manager help
Checks insurance coverage, helps with eligibility and enrollment in financial assistance programs, and connects you to the specialty pharmacy.
The official page does not say who qualifies. Ask the program. · source
Good to know: Sentynl Therapeutics' support program; Mon-Fri 8 AM-8 PM ET. Official pages mention 'financial assistance programs' but do not name a copay card or free-drug program or say who qualifies. Call 1-888-251-2800 to ask.
Clinical trial results
The pivotal evidence came from a long-term NIH study led by Dr. Stephen Kaler. Early-treated newborns achieved median survival of 14.8 years (177.1 months), compared to about 1.5 years (17.6 months) in an untreated external comparison group, a 78% reduction in the risk of death. Multiple patients survived beyond 12 years. The study demonstrated that treatment timing is the single most important predictor of outcomes.
Development history
Copper histidinate was developed over decades at the National Institutes of Health by Dr. Stephen Kaler, who demonstrated that early copper replacement could transform outcomes in Menkes disease. Cyprium Therapeutics (a Fortress Biotech subsidiary) licensed the compound as CUTX-101, and in December 2023 Sentynl Therapeutics, a Zydus Lifesciences company, took over full responsibility for its development and commercialization. The FDA approved Zycubo on January 12, 2026, making it the first approved treatment for Menkes disease, a historic milestone for the rare disease community.
Explore Menkes Disease trials
Common questions about Copper histidinate
▸What is Copper histidinate (Zycubo)?
The first and only FDA-approved treatment for Menkes disease. Copper histidinate bypasses the defective ATP7A copper transporter to deliver copper directly into the bloodstream, dramatically improving survival when treatment begins in the first weeks of life.
▸How does Copper histidinate work?
In Menkes disease, a genetic defect in the ATP7A gene prevents copper absorbed from food from being transported out of intestinal cells and into the bloodstream. This creates a paradox: copper accumulates uselessly in the gut while the brain, bones, and other organs starve for it. Copper is essential for enzymes that build brain connections, produce energy in cells, create connective tissue, and synthesize neurotransmitters.
Copper histidinate works by providing copper in a form (bound to the amino acid histidine) that can enter the bloodstream through subcutaneous injection, completely bypassing the broken intestinal transport system. Once in the blood, copper-histidine complexes are taken up by cells and used to activate the copper-dependent enzymes that Menkes patients lack.
Timing is everything. In the pivotal NIH study, babies who received copper histidinate early in life had median survival of 14.8 years, compared to about 1.5 years (17.6 months) in an untreated comparison group. The treatment must begin before irreversible brain damage occurs, ideally within the first weeks of life, making early diagnosis critical.
▸What are the side effects of Copper histidinate?
The label warns that extra copper can build up and may cause kidney injury, liver problems, and blood abnormalities such as anemia. Blood tests (copper, ceruloplasmin, electrolytes, kidney and liver function, and blood counts) are needed before starting, every 6 weeks for the first 6 months, every 3 months for the next 18 months, and every 6 months after that. The most common side effects in studies included infections such as pneumonia, breathing problems including respiratory failure, seizures, vomiting, fever, anemia, and injection site reactions. Because the studies had no comparison group, it is hard to tell which of these were caused by the medicine and which by Menkes disease itself. Because Menkes disease involves progressive neurological decline regardless of treatment timing, distinguishing drug effects from disease effects requires careful clinical monitoring.
▸How is Copper histidinate taken?
Given as a subcutaneous injection (under the skin). Zycubo is FDA-approved for children (pediatric patients) with Menkes disease. It is not approved for occipital horn syndrome (OHS). For infants under 1 year, the dose is 1.45 mg twice daily. For patients aged 1 to 17, the dose is 1.45 mg once daily. Treatment should begin as early as possible after diagnosis, ideally within the first weeks of life, and continues through childhood.
▸Is Copper histidinate FDA approved?
Yes, Copper histidinate (Zycubo) is FDA approved (2026) for the treatment of Menkes Disease.
▸What is Zycubo used for?
Zycubo (copper histidinate) is the first and only FDA-approved treatment for Menkes disease, a rare genetic disorder that prevents the body from distributing copper to the brain and other organs.
▸Why is early treatment important for Menkes disease?
Research shows that starting copper histidinate treatment within the first weeks of life, before irreversible brain damage occurs, dramatically improves survival. Early-treated babies had median survival of 14.8 years versus about 1.5 years (17.6 months) in untreated patients.
▸How does copper histidinate work in Menkes disease?
Menkes disease is caused by a broken copper transporter (ATP7A) in the gut. Copper histidinate bypasses this defect by delivering copper directly into the bloodstream through subcutaneous injection, restoring copper supply to the brain and other organs.
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- U.S. Food and Drug Administration · January 12, 2026. FDA approves copper histidinate (Zycubo) for Menkes disease. https://www.fda.gov/news-events/press-announcements/fda-approves-first-treatment-children-menkes-disease
- New England Journal of Medicine. Neonatal Diagnosis and Treatment of Menkes Disease. https://www.nejm.org/doi/full/10.1056/NEJMoa070613
- Sentynl Therapeutics. Zycubo (copper histidinate) for Menkes Disease. https://zycubo.com/