Zycubo (copper histidinate) / Fortress, Zydus Lifesciences - LARVOL DELTA

Copper Nanoclusters Delivered Prenatally Mitigate Neurological, Mitochondrial, and Vascular Deficits in Menkes Disease (SSIEM 2026) - "In comparison, copper histidinate exhibited more limited effects. These findings highlight the unique potential of prenatal intervention targeting copper deficiency to mitigate neurological, mitochondrial, and vascular deficits in Menkes disease. Administering CuNC during the fetal period may represent a major advance for early therapeutic management, offering a preventive strategy capable of acting before symptom onset."

Cardiovascular • ATP7A

"A new era in Menkes disease management: the disease-modifying impact of Zycubo (copper histidinate)". (PubMed, Ann Med Surg (Lond)) - No abstract available

Journal

FDA approval of copper histidinate (Zycubo) for Menkes disease: a therapeutic breakthrough in a rare pediatric neurodegenerative disorder. (PubMed, Ann Med Surg (Lond)) - "Despite its clinical benefits, treatment may be associated with adverse effects including infections, respiratory complications, anemia, and injection-site reactions, necessitating careful monitoring during therapy. Continued research is required to evaluate long-term safety, optimize therapeutic strategies, and further improve outcomes for affected children."

FDA event • Journal • CNS Disorders • Epilepsy • Hematological Disorders • Infectious Disease • Pediatrics • Respiratory Diseases • ATP7A

AAV9 gene therapy and/or CuHis for copper transporter 1 (CTR1) deficiency, a newly identified disorder of cerebral and cerebellar degeneration (ASGCT 2026) - "We generated a mouse model that harbors the CTR1-R95H variant, characterized clinical and biochemical phenotypes, and are evaluating experimental treatment strategies including intravenous AAV9-CTR1, and subcutaneous copper histidinate (CuHis, recently FDA- approved), alone and in combination...(A) Catecholamine synthesis pathway (B) Analyses of brain neurochemicals (C) CuHis treatment of homozygous CTR1R95H mice improves growth significantly. (D) Map of the AAV construct."

Gene therapy • CNS Disorders • Developmental Disorders • Epilepsy • Gene Therapies • SLC31A1

Copper Histidinate: Pediatric First Approval. (PubMed, Paediatr Drugs) - "Orphan Designation was granted by The European Commission to copper histidinate for the treatment of Menkes disease. This article summarizes the milestones in the development of copper histidinate leading to this first approval for Menkes disease in pediatric patients."

Journal • Review • Gastrointestinal Disorder • Genetic Disorders • Pediatrics • ATP7A

Fortress Biotech’s Subsidiary Cyprium Therapeutics Closes Sale of Rare Pediatric Disease Priority Review Voucher for $205 Million (GlobeNewswire) - "The PRV was issued upon approval of ZYCUBO by the U.S. Food and Drug Administration ('FDA') on January 12, 2026. Pursuant to the transaction with Sentynl, the PRV was immediately transferred to Cyprium and has now been sold by Cyprium. Cyprium remains eligible to receive tiered royalties on net sales of ZYCUBO and up to approximately $128 million in aggregate sales milestones from Sentynl. Cyprium is obligated to pay 20% of the proceeds from the PRV sale to the Eunice Kennedy Shriver National Institute of Child Health and Human Development, an institute of the National Institutes of Health."

Commercial • Rare Diseases

Menkes Disease: Another Example of Progress in the Development of Pharmaceuticals for Rare Childhood Diseases, But Much Still Remains to Be Done. (PubMed, Clin Ther) - No abstract available

Journal

ZYCUBO (copper histidinate). (PubMed, Clin Ther) - No abstract available

Journal

Zycubo (copper histidinate), the first treatment for pediatric Menkes disease. (PubMed, Trends Pharmacol Sci) - No abstract available

Journal • Pediatrics

Long Term Follow-up on Menkes Disease Patients (clinicaltrials.gov) - P=N/A | N=50 | Active, not recruiting | Sponsor: Sentynl Therapeutics, Inc. | Enrolling by invitation ➔ Active, not recruiting | Trial completion date: Dec 2023 ➔ Aug 2026 | Trial primary completion date: Dec 2023 ➔ Feb 2026

Enrollment closed • Trial completion date • Trial primary completion date

Fortress Biotech, Inc…announced that Cyprium entered into a definitive asset purchase agreement to sell its Rare Pediatric Disease Priority Review Voucher (“PRV”) for gross proceeds of $205 million upon the closing of the transaction. (GlobeNewswire) - "Pursuant to the transaction with Sentynl, the PRV was immediately transferred to Cyprium. Cyprium remains eligible to receive tiered royalties on net sales of ZYCUBO and up to $129 million in aggregate development and sales milestones from Sentynl. Cyprium is also obligated to pay 20% of the proceeds from a PRV sale to the Eunice Kennedy Shriver National Institute of Child Health and Human Development, an institute of the National Institutes of Health."

Commercial • Rare Diseases

CRISPR prime editing as a promising therapeutic avenue for Menkes disease: the next step in correcting ATP7A mutations. (PubMed, Ann Med Surg (Lond)) - "Existing therapies, such as copper histidinate injections, have limited neurological effects because of inefficient brain copper uptake...In this letter, we will discuss ATP7A variants that may be prime-editable and suggest an ex vivo approach for correction in induced pluripotent stem cells generated from Menkes patients with validation of function to follow. There is currently no literature that demonstrates PE for Menkes disease to the best of our knowledge and therefore represents a unique approach for a novel gene-level intervention for this fatal disease."

Journal • Gene Therapies • ATP7A

Zydus Lifesciences, US-based subsidiary Sentynl Therapeutics has secured the US Food and Drug Administration (FDA) approval for Zycubo (copper histidinate),a treatment of Menkes disease in pediatric patients. (The Economic Times) - "The approved drug is a subcutaneous injectable formulation of copper histidinate that restores copper homeostasis and maintains copper levels in patients with Menkes disease."

FDA approval • Rare Diseases

Fortress Biotech, Inc…and its majority-owned subsidiary, Cyprium Therapeutics, Inc…announced that the U.S. Food and Drug Administration (“FDA”) has accepted the resubmission of the New Drug Application (“NDA”) for CUTX-101 (copper histidinate), intended to treat Menkes disease in pediatric patients. (Fortress Biotech Press Release) - "The resubmission has been accepted as a Class 1 resubmission and as a result, the new Prescription Drug User Fee Act (PDUFA) target action date for the NDA is January 14, 2026...On November 14, 2025, Sentynl resubmitted the revised NDA after receiving a complete response letter ('CRL') from the FDA on September 30, 2025, which CRL cited observations regarding the manufacturing site’s cGMP compliance."

FDA filing • PDUFA • Genetic Disorders

Clinical Outcomes of Copper Histidinate Treatment in Menkes Disease: A Single-Center Retrospective Case Series from an Expanded Access Program (AES 2025) - "MD is a progressive neurodegenerative disorder with dismal prognosis. Parenteral CuHis under an EAP showed a favorable safety profile and signs of clinical stabilization and neurocognitive benefit in our cohort. Early treatment, ideally in the neonatal period, even before seizure onset, is associated with improved outcomes."

Clinical data • Retrospective data • Absence Seizure Disorder • CNS Disorders • Epilepsy • Nephrology • Palliative care • Urology • ATP7A

Fortress Biotech reports NDA resubmission for Menkes disease treatment (Investing.com) - "Cyprium will retain ownership of any Priority Review Voucher that may be issued if the NDA is approved. The company is also eligible to receive royalties and up to $129 million in aggregate development and sales milestone payments."

Commercial • FDA filing • Genetic Disorders • Rare Diseases

Fortress Biotech, Inc…and its majority-owned subsidiary, Cyprium Therapeutics, Inc…announced that the U.S. Food and Drug Administration (“FDA”) has issued a Complete Response Letter (“CRL”) relating to the New Drug Application (“NDA”) for CUTX-101 (copper histidinate), intended to treat Menkes disease in pediatric patients. (GlobeNewswire) - "The CRL noted cGMP deficiencies had been observed at the facility where CUTX-101 is manufactured."

CRL • Genetic Disorders

Intravenous AAV9-ATP7A plus subcutaneous copper histidinate optimizes outcomes in a lethal Menkes disease mouse model. (PubMed, Sci Adv) - "In conjunction with subcutaneous injections of clinical-grade copper histidinate in the first month of life, 95% long-term survival was attained, which was correlated with improvements in serum and brain copper levels, brain neurochemical profiles, somatic growth, and neuromotor function. The notable results support a trial of this treatment combination in affected male newborns with Menkes disease."

Journal • Preclinical • CNS Disorders • Epilepsy • Gene Therapies • ATP7A

OVERCOMING BARRIERS IN MENKES DISEASE: A STANDARDIZED HIGH QUALITY AND STABLE INJECTABLE COPPER HISTIDINATE. (PubMed, J Pharm Sci) - "This study extends and optimizes the manufacturing procedure by incorporating active principles as salts or neutral substances and accommodating a broader pH range. The Cu-Hiinj 1:3 formulation not only offers enhanced stability but also shows potential for industrial production, thus improving access to Menkes disease treatment while ensuring safety and efficacy."

Journal • Rare Diseases

Fortress Biotech and Cyprium Therapeutics Announce U.S. FDA Acceptance and Priority Review of NDA for CUTX-101 for Treatment of Menkes Disease (GlobeNewswire) - "Fortress Biotech, Inc....today announced the acceptance for review of the New Drug Application ('NDA') by the U.S. Food and Drug Administration ('FDA') for CUTX-101 (Copper Histidinate) for the treatment of Menkes disease, a rare X-linked recessive pediatric disease caused by gene mutations of the copper transporter ATP7A. The NDA has been granted Priority Review and assigned a Prescription Drug User Fee Act (PDUFA) target action date of June 30, 2025...The CUTX-101 NDA submission is supported by positive topline clinical efficacy results for CUTX-101, demonstrating statistically significant improvement in overall survival for Menkes disease subjects who received early treatment with CUTX-101...If the CUTX-101 NDA is approved, the product may be eligible for a Rare Pediatric Disease Priority Review Voucher (PRV), for which Cyprium would retain ownership...Cyprium is also eligible to receive royalties and up to $129 million in aggregate development and sales milestones from Sentynl."

Commercial • FDA filing • PDUFA • Priority review • Genetic Disorders

Huppke-Brendel syndrome: Novel cases and a therapeutic trial with ketogenic diet and N-acetylcysteine. (PubMed, JIMD Rep) - "Therapeutic trials with copper histidinate failed to achieve any clinical improvement. The overall metabolic pattern shows a trend toward lowered levels of N-acetylated amino acids in CSF and to a lesser extent in plasma. Although there are some assumptions, the function of AT-1 is still not clear and further studies are needed to better understand mechanisms underlying this complex disorder."

Journal • Pediatrics • SLC33A1

EFFICACY OF A COPPER NANOCLUSTERS TO TREAT A MOUSE MODEL OF MENKES DISEASE (SSIEM 2024) - "Copper-histidinate is the current treatment but does not improve the neurologic status of these patients... We demonstrated that CuNC, thanks to its very little size (< 1nm), is able to cross the physiological barriers (including the BBB) and to restore the copper-enzymes activities. Due to these results, we obtain the Orphan Drug Designation (ODD) by the EMA in 2023 and we hope to begin the phase I/II trial in children with MD by the end of 2024."

Preclinical • Cardiovascular • CNS Disorders • Osteoporosis • Rheumatology • Tyrosinase

Long Term Follow-up on Menkes Disease Patients (clinicaltrials.gov) - P=N/A | N=50 | Enrolling by invitation | Sponsor: Cyprium Therapeutics, Inc. | Trial completion date: Dec 2022 ➔ Dec 2023 | Trial primary completion date: Dec 2022 ➔ Dec 2023

Trial completion date • Trial primary completion date

LAT1 (SLC7A5) catalyzes copper(histidinate) transport switching from antiport to uniport mechanism. (PubMed, iScience) - "Crystals of the monomeric species Cu(His) were obtained in our experimental conditions and the actual transport of the complex was evaluated by a combined strategy of bioinformatics, site-directed mutagenesis, radiolabeled transport, and mass spectrometry analysis. The LAT1-mediated transport of Cu(His) may have profound implications for both the treatment of copper dysmetabolism diseases, such as the rare Menkes disease, and of cancer as an alternative to platinum-based therapies."

Journal • Metabolic Disorders • Oncology • SLC7A5

Characterization of the Mottled-Blotchy Mouse Model of Abnormal Copper Transport (ASGCT 2023) - "We sought to quantify the amount of properly spliced Atp7a transcript in mo-blotchy mice in order to better understand its phenotype and response to AAV9-mediated gene replacement in combination with subcutaneous copper histidinate (CuHis)...We also identified one female pup with skewed X-inactivation leading to a severe phenotype and premature death. Cultured fibroblasts obtained from this mouse are under investigation for gene therapy mediated modulation of X-inactivation.The results from this study advance understanding of clinical and biochemical aspects of abnormal human copper transport and provide insight and direction for rational treatment approaches to Menkes disease and its milder variants."

Preclinical • Gene Therapies • Genetic Disorders • ATP7A