MIAMI, Florida — January 13, 2026 — Leads & Copy —
Fortress Biotech, Inc. (Nasdaq: FBIO) and its majority-owned subsidiary, Cyprium Therapeutics, Inc., announced today that the U.S. Food and Drug Administration (“FDA”) has approved ZYCUBO® (copper histidinate, formerly known as CUTX-101) for the treatment of Menkes disease in pediatric patients.
A Rare Pediatric Disease Priority Review Voucher (PRV) was issued in connection with FDA approval and will be transferred to Cyprium, pursuant to the transaction with Sentynl Therapeutics, Inc. (“Sentynl”), a U.S.-based biopharmaceutical company wholly-owned by Zydus Lifesciences Limited (“Zydus Group”), which assumed full responsibility for the development and commercialization of CUTX-101 from Cyprium in December 2023. Cyprium is also eligible to receive tiered royalties on net sales of ZYCUBO and up to $129 million in aggregate development and sales milestones from Sentynl.
ZYCUBO® is a subcutaneous injectable formulation of copper histidinate that restores copper homeostasis and maintains copper levels in patients with Menkes disease. Menkes disease is a rare X-linked recessive pediatric disease caused by mutations of the copper transporter ATP7A encoded by the ATP7A gene. Patients with Menkes disease are born with the inability to absorb dietary copper and subsequently have impaired copper transport across the blood-brain barrier, and, until now, there has been no approved treatment in the United States.
According to Lindsay A. Rosenwald, M.D., Fortress’ Chairman, President and Chief Executive Officer and Cyprium’s Chairman, the approval of ZYCUBO is a pivotal milestone for their company and patients suffering from Menkes Disease, as it is the first and only FDA-approved treatment for this rare, often fatal, pediatric disease. With three FDA approvals received in the last 15 months, for Emrosi™, UNLOXCYT™ (cosibelimab-ipdl), and now ZYCUBO, along with the recent sale of Checkpoint Therapeutics to Sun Pharma for approximately $28 million upfront to Fortress, plus the potential for an additional contingent value right (CVR) payment and ongoing royalties on future sales of UNLOXCYT, they believe that their business model has demonstrated measurable success and continued execution across the portfolio. Rosenwald said they look forward to the potential achievement of additional upcoming milestones across their extensive pipeline of commercial and clinical-stage assets.
Lung S. Yam, M.D., Ph.D., Cyprium’s President and Chief Executive Officer, stated that the development and approval of ZYCUBO are the culmination of more than three decades of hard work and dedication by many people, including the team members at Cyprium, Fortress and Sentynl, and expressed gratitude to the Menkes disease patients and their families who participated in the clinical studies and helped advance their understanding of this devastating disease.
The approval is supported by positive topline clinical efficacy results for ZYCUBO, demonstrating statistically significant improvement in overall survival for Menkes disease subjects who received early treatment (“ET”) with ZYCUBO, compared to an untreated contemporaneous external control (“EC”) cohort, with a nearly 80% reduction in the risk of death. Median overall survival (“OS”) was 177.1 months for ZYCUBO ET cohort compared to 17.6 months for the EC cohort.
The most common adverse reactions (incidence ≥7%) were pneumonia, viral infection, respiratory failure, seizure, bacterial infection, hemorrhage, hypotension, vomiting, tachycardia, pyrexia, volume depletion, fracture, dyspnea, transaminases elevation, diarrhea, fungal infection, anemia, and local administration reaction.
ZYCUBO has received Breakthrough Therapy, Fast Track, Rare Pediatric Disease, and Orphan Drug Designation from the FDA. Copper histidinate has also been granted Orphan Designation by the European Medicines Agency.
Menkes disease is a rare X-linked recessive pediatric disease caused by gene mutations of the copper transporter ATP7A. The minimum birth prevalence for Menkes disease is believed to be 1 in 34,810 live male births, and potentially as high as 1 in 8,664 live male births, based on recent genome-based ascertainment. The condition is characterized by distinctive clinical features, including sparse and depigmented hair (“kinky hair”), connective tissue problems, and severe neurological symptoms such as seizures, hypotonia, failure to thrive, and neurodevelopmental delays. Mortality is high in untreated Menkes disease, with many patients dying between 2-3 years of age. Milder versions of ATP7A mutations are associated with conditions other than Menkes Disease, such as Occipital Horn Syndrome and ATP7A-related Distal Motor Neuropathy.
ZYCUBO® is the first and only FDA-approved, bioavailable copper replacement therapy for the treatment of Menkes disease, a copper transport deficiency caused by mutations in ATP7A. ZYCUBO is a subcutaneous injectable formulation of copper histidinate that is given daily to deliver elemental copper to the body. In a pooled analysis of two open label, single-arm clinical trials, early treatment with ZYCUBO (ZYCUBO-ET) demonstrated significant improvement in overall survival for Menkes disease patients with a nearly 80% reduction in the risk of death compared to the overall survival of patients in the untreated contemporaneous external control cohort. For more information, visit https://zycubo.com.
ZYCUBO is indicated for the treatment of Menkes disease in pediatric patients and is not indicated for the treatment of Occipital Horn Syndrome.
The most common adverse reactions (>7%) were pneumonia (30%), viral infection (27%), respiratory failure1 (23%) (including cardiopulmonary failure (9%)), seizure (23%), bacterial infection2 (20%) (including renal and urinary tract infection (9%)), hemorrhage (18%), hypotension (16%), vomiting (15%), tachycardia (12%), pyrexia (12%), volume depletion (12%), fracture (12%), dyspnea (12%), transaminases elevation (10%), diarrhea (10%), fungal infection (9%), anemia (9%), and local administration reaction (7%).
There are no available data on ZYCUBO use during pregnancy to evaluate for a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes. Animal reproduction studies have not been conducted with ZYCUBO.
There are no available data on the presence of ZYCUBO in either human or animal breast milk, the effects on the breastfed infant, or the effects on milk production.
The safety and effectiveness of ZYCUBO for the treatment of Menkes disease have been established in pediatric patients. Clinical trials of ZYCUBO did not include patients 65 years of age and older.
Jaclyn Jaffe
Fortress Biotech, Inc.
(781) 652-4500
ir@fortressbiotech.com
Tony Plohoros
6 Degrees
(908) 591-2839
tplohoros@6degreespr.com
Source: Fortress Biotech
