Fortress Biotech Shares Drop After FDA Letter for CUTX-101 Manufacturing Facility

By Chris Wack

Fortress Biotech shares were trading 36% lower, at $2.35, after the company said the Food and Drug Administration issued a Complete Response Letter to its majority-owned subsidiary, Cyprium Therapeutics, relating to a new drug application for CUTX-101 copper histidinate.

CUTX-101 is intended to treat Menkes disease in pediatric patients.

In December 2023, Sentynl Therapeutics assumed full responsibility for the development and commercialization of CUTX-101 from Cyprium.

The CRL noted current Good Manufacturing Practice deficiencies had been observed at the facility where CUTX-101 is manufactured. The facility recently provided responses to the FDA's September inspection, and Sentynl expects to request a meeting with the FDA to discuss the CRL and resubmission of the CUTX-101 NDA.

The CRL didn't cite any other approvability concerns, nor did it identify any deficiencies in CUTX-101's efficacy and safety data.

Under the agreement, Sentynl will transfer to Cyprium, if issued upon approval, a Rare Pediatric Disease Priority Review Voucher, and Cyprium will also be eligible to receive royalties on sales of CUTX-101 and up to $129 million in 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.

Cyprium said it expects Sentynl will work expeditiously to address the FDA's concerns and pursue resubmission promptly.

Write to Chris Wack at chris.wack@wsj.com

(END) Dow Jones Newswires

October 01, 2025 11:07 ET (15:07 GMT)