Fortress Biotech and Cyprium Therapeutics Announce FDA Approval of ZYCUBO® for Menkes Disease
Miami, Jan. 13, 2026 – Fortress Biotech, Inc. (Nasdaq: FBIO) and its majority-owned subsidiary, Cyprium Therapeutics, Inc., have announced that the U.S. Food and Drug Administration (FDA) has granted approval for ZYCUBO® (copper histidinate), the first and only authorized treatment for Menkes disease in pediatric patients. This significant milestone marks a breakthrough for both the company and families affected by this rare condition.
Key Developments Surrounding ZYCUBO® Approval
The recent approval is part of a transition initiated in December 2023 when Sentynl Therapeutics, Inc., a subsidiary of Zydus Lifesciences Limited, took over the development and commercialization rights for ZYCUBO from Cyprium. A Rare Pediatric Disease Priority Review Voucher, issued alongside the FDA approval, will be transferred to Cyprium, which is also eligible for tiered royalties and up to $129 million in total development and sales milestones from Sentynl.
Menkes Disease Overview
Menkes disease is a rare X-linked recessive disorder stemming from mutations in the ATP7A gene, which leads to impaired copper absorption in the body. Prior to ZYCUBO's approval, there were no FDA-approved treatments available in the United States. Patients with Menkes disease often exhibit severe neurological symptoms along with other critical medical issues.
- Birth prevalence: Estimated between 1 in 34,810 and 1 in 8,664 live male births.
- Clinical symptoms: Sparse or depigmented hair, hypotonia, seizures, and developmental delays.
- Mortality rates: High mortality risk for untreated patients, often dying by the age of 2-3 years.
Impact of ZYCUBO® on Patient Care
ZYCUBO® is a subcutaneous injectable therapy designed to restore copper homeostasis in patients suffering from Menkes disease. The approval of ZYCUBO is highlighted by clinical efficacy results, showing a nearly 80% reduction in mortality risk for those who received early treatment compared to an untreated control group, with median overall survival significantly improving to 177.1 months.
Statements from Company Leadership
“The approval of ZYCUBO is a pivotal milestone for our company and patients suffering from Menkes Disease, representing the first and only FDA-approved treatment for this often-fatal pediatric condition,” stated Dr. Lindsay A. Rosenwald, Chairman and CEO of Fortress and Cyprium. He further highlighted the company’s track record with three FDA approvals in the last 15 months, reflecting ongoing success and robust execution of their business model.
Dr. Lung S. Yam, President and CEO of Cyprium, expressed gratitude to the patients involved in clinical trials: “The development and approval of ZYCUBO represent over three decades of dedication and hard work from various contributors, and we owe our gratitude to the families who participated in our studies.”
Safety Information and Designations
ZYCUBO has received several designations from the FDA, including Breakthrough Therapy and Orphan Drug Designation, in recognition of its critical role in treating Menkes disease. Most common adverse reactions (occurring in ≥7% of participants) include pneumonia, viral infections, and respiratory failure, highlighting the need for careful patient monitoring during treatment.
Conclusion
The approval of ZYCUBO® is a breakthrough for both Fortress Biotech and Cyprium Therapeutics, aligning with their strategic objectives to provide innovative treatments for rare diseases. This marks a significant advancement in the medical community's ability to manage Menkes disease and offers hope to affected families. Investors and stakeholders can follow developments related to Fortress Biotech via their stock symbol FBIO for ongoing updates.