Menkes disease is a rare X-linked recessive disorder caused by mutations in the ATP7A gene, resulting in impaired copper absorption and transport.
Zycubo is administered subcutaneously to restore copper balance and maintain appropriate copper levels in affected patients.
The FDA granted the approval based on the positive top line clinical efficacy results. The data showed a statistically significant increase in overall survival for patients who started Zycubo treatment early compared to a contemporaneous external control group not receiving treatment.
Median overall survival reached 177.1 months in the early treatment group, while the untreated group had a median survival of 17.6 months.
Adverse reactions occurring in at least 7% of cases included bacterial infections, fever, haemorrhage, low blood pressure, respiratory failure, and vomiting.
Difficulty breathing, fractures, diarrhoea, increased transaminase levels, anaemia, fungal infections and reactions at the site of administration were also reported.
Cyprium Therapeutics president and CEO Lung Yam said: “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.
“We would like to express our gratitude to the Menkes disease patients and their families who participated in the clinical studies and helped advance our understanding of this devastating disease.”
In December 2023, Sentynl Therapeutics, a biopharmaceutical company owned by Zydus Lifesciences, assumed responsibility for all development and commercialisation activities related to Zycubo from Cyprium Therapeutics.
As part of this transaction, a rare paediatric disease priority review voucher (PRV) issued with FDA approval will be transferred to Cyprium. Additionally, Cyprium is entitled to tiered royalties on net sales and may receive up to $129m in development and sales milestone payments from Sentynl.
Zycubo received breakthrough therapy, fast track, rare paediatric disease and orphan drug designations from the FDA. It has also been granted orphan designation by the European Medicines Agency (EMA).
In January 2025, the FDA accepted for filing Sentynl Therapeutics’ new drug application (NDA) for CUTX-101 to treat Menkes disease and granted it priority review.