Fortress Biotech And Cyprium Therapeutics Announce FDA Issues CRL Relating To NDA For CUTX-101, Intended To Treat Menkes Disease In Pediatric Patients

Author: Benzinga Newsdesk | October 01, 2025 07:15am

Fortress Biotech, Inc. (NASDAQ:FBIO) ("Fortress") and its majority-owned subsidiary, Cyprium Therapeutics, Inc. ("Cyprium"), today 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.

In December 2023, Sentynl Therapeutics, Inc. ("Sentynl"), a U.S.-based biopharmaceutical company wholly-owned by Zydus Lifesciences, Ltd. ("Zydus Group") assumed full responsibility for the development and commercialization of CUTX-101 from Cyprium. Cyprium expects its partner, Sentynl, will work expeditiously to address the FDA's concerns and pursue resubmission promptly.

The CRL noted cGMP deficiencies had been observed at the facility where CUTX-101 is manufactured. The facility recently provided responses to the FDA's September 2025 re-inspection of the facility, and Sentynl expects to request a meeting with the FDA to discuss the CRL and resubmission of the CUTX-101 NDA. The CRL did not cite any other approvability concerns, nor did it identify any deficiencies in CUTX-101's efficacy and safety data.

Pursuant to the transaction with Sentynl, Sentynl will transfer to Cyprium, if issued upon approval, a Rare Pediatric Disease Priority Review Voucher ("PRV"), and Cyprium will also be eligible to receive royalties on net sales of CUTX-101 and up to $129 million in aggregate development and sales milestones from Sentynl.

The CUTX-101 NDA was initially granted Priority Review by the FDA and is supported by positive topline clinical efficacy results for CUTX-101, demonstrating significant improvement in overall survival for Menkes disease subjects who received early treatment with CUTX-101.

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