Fortress Biotech Shares Plunge 31% as FDA Rejects Rare Disease Drug CUTX-101
ByAinvest
Wednesday, Oct 1, 2025 9:03 am ET1min read
FBIO--
Menkes disease is a rare pediatric condition characterized by severe neurological symptoms and caused by mutations in the copper transporter gene ATP7A. The FDA's decision is a significant setback for Fortress Biotech, which has been focused on developing treatments for rare diseases. CUTX-101 had shown promising clinical results, demonstrating significant improvement in overall survival for Menkes disease subjects who received early treatment .
The CRL highlighted cGMP (current Good Manufacturing Practice) deficiencies at the manufacturing facility, raising concerns about the quality control processes and reliability of the product. However, the FDA did not raise concerns about the drug's efficacy or safety data, indicating a strong potential for future resubmission [1].
Sentynl Therapeutics, Inc., a U.S.-based biopharmaceutical company wholly-owned by Zydus Lifesciences, Ltd., assumed full responsibility for the development and commercialization of CUTX-101 from Cyprium Therapeutics, a majority-owned subsidiary of Fortress Biotech. Sentynl plans to address the FDA's concerns and seek a meeting regarding the resubmission of the NDA. Upon approval, Sentynl will transfer a Rare Pediatric Disease Priority Review Voucher to Cyprium and pay royalties and milestones amounting to up to $129 million [1].
The FDA's decision has negatively impacted Fortress Biotech, as Cyprium Therapeutics is a majority-owned subsidiary and relies on the successful development of CUTX-101. The decline in stock price reflects investor concerns about the potential delay in market entry and the impact on investor confidence [1].
Fortress Biotech (NASDAQ:FBIO) shares fell 31% in the premarket after the FDA declined to approve CUTX-101, a treatment for Menkes disease, a rare condition. The company developed the drug with India-based partner Zydus Lifesciences. The FDA's decision is a significant setback for Fortress Biotech, which is focused on developing treatments for rare diseases.
Fortress Biotech (NASDAQ: FBIO) shares dropped by 31% in the premarket trading session following the U.S. Food and Drug Administration's (FDA) decision to decline the approval of CUTX-101, a treatment for Menkes disease. The FDA issued a Complete Response Letter (CRL) for the New Drug Application (NDA) of CUTX-101, citing manufacturing deficiencies at the facility where the drug is produced [1].Menkes disease is a rare pediatric condition characterized by severe neurological symptoms and caused by mutations in the copper transporter gene ATP7A. The FDA's decision is a significant setback for Fortress Biotech, which has been focused on developing treatments for rare diseases. CUTX-101 had shown promising clinical results, demonstrating significant improvement in overall survival for Menkes disease subjects who received early treatment .
The CRL highlighted cGMP (current Good Manufacturing Practice) deficiencies at the manufacturing facility, raising concerns about the quality control processes and reliability of the product. However, the FDA did not raise concerns about the drug's efficacy or safety data, indicating a strong potential for future resubmission [1].
Sentynl Therapeutics, Inc., a U.S.-based biopharmaceutical company wholly-owned by Zydus Lifesciences, Ltd., assumed full responsibility for the development and commercialization of CUTX-101 from Cyprium Therapeutics, a majority-owned subsidiary of Fortress Biotech. Sentynl plans to address the FDA's concerns and seek a meeting regarding the resubmission of the NDA. Upon approval, Sentynl will transfer a Rare Pediatric Disease Priority Review Voucher to Cyprium and pay royalties and milestones amounting to up to $129 million [1].
The FDA's decision has negatively impacted Fortress Biotech, as Cyprium Therapeutics is a majority-owned subsidiary and relies on the successful development of CUTX-101. The decline in stock price reflects investor concerns about the potential delay in market entry and the impact on investor confidence [1].

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