FBIO updates on CUTX-101 NDA and $129M milestone potential

Rhea-AI Filing Summary

Fortress Biotech reports that its partner Sentynl Therapeutics has resubmitted the New Drug Application (NDA) for CUTX-101 to the U.S. Food and Drug Administration. CUTX-101 (copper histidinate) is intended to treat Menkes disease in pediatric patients and previously received a Complete Response Letter from the FDA on October 1, 2025. Sentynl, which assumed full responsibility for development and commercialization of CUTX-101 from Cyprium Therapeutics in December 2023, is leading the resubmission. Cyprium will retain ownership of any Priority Review Voucher that may be issued if the NDA is approved and is eligible to receive royalties and up to $129 million in aggregate development and sales milestone payments.

Insights

Biotech & Regulatory Affairs Analyst

Resubmission of CUTX-101’s NDA revives a key rare-disease opportunity for Fortress Biotech and Cyprium.

The update centers on CUTX-101, a copper histidinate therapy for pediatric Menkes disease. After the FDA issued a Complete Response Letter on October 1, 2025, Sentynl Therapeutics, which had already assumed full development and commercialization responsibility in December 2023, has now resubmitted the NDA. This keeps the regulatory path active without Fortress Biotech or Cyprium bearing primary development responsibility.

Economically, Cyprium will retain ownership of any Priority Review Voucher that may be granted upon NDA approval and is eligible for royalties plus up to $129 million in aggregate development and sales milestones. A Priority Review Voucher can have significant monetary value, but both the voucher and milestones depend on eventual FDA approval and commercial performance. Overall impact will be determined by the FDA’s decision on the resubmitted NDA and subsequent market uptake, which are not specified here.

8-K Event Classification

Item 8.01 — Other Events

1 item

Item 8.01 Other Events Other

Voluntary disclosure of events the company deems important to shareholders but not covered by other items.

Understanding 8-K Material Events →

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT 

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of report (Date of earliest event reported): November 14, 2025

Fortress Biotech, Inc.

(Exact Name of Registrant as Specified in Charter)

Delaware		001-35366		20-5157386
(State or Other Jurisdiction of Incorporation)		(Commission File Number)		(IRS Employer Identification No.)
1111 Kane Concourse, Suite 301 Bay Harbor Islands, FL 33154
(Address of Principal Executive Offices)

(781) 652-4500

(Registrant's telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act.

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act.

¨ Pre-commencement communications pursuant to Rule 14d-2b under the Exchange Act.

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

Securities registered pursuant to Section 12 (b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock	FBIO	Nasdaq Capital Market
9.375% Series A Cumulative Redeemable Perpetual Preferred Stock	FBIOP	Nasdaq Capital Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.      ¨

Item 8.01.    Other Events.

As previously disclosed, on October 1, 2025, Fortress Biotech, Inc. (the “Company”) and its majority-owned subsidiary, Cyprium Therapeutics, Inc. (“Cyprium”), announced that the U.S. Food and Drug Administration (the “FDA”) had issued a Complete Response Letter 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., assumed full responsibility for the development and commercialization of CUTX-101 from Cyprium.

On November 14, 2025, Sentynl notified Cyprium that Sentynl had resubmitted the NDA for CUTX-101 to the FDA. Cyprium will retain ownership over any Priority Review Voucher that may be issued upon NDA approval and is eligible to receive royalties and up to $129 million in aggregate development and sales milestones.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	Fortress Biotech, Inc.
	(Registrant)
Date: November 17, 2025
	By:	/s/ David Jin
		David Jin
		Chief Financial Officer

FAQ

What did Fortress Biotech (FBIO) announce regarding CUTX-101?

Fortress Biotech reported that Sentynl Therapeutics has resubmitted the New Drug Application for CUTX-101, a copper histidinate treatment for pediatric Menkes disease, to the FDA after a prior Complete Response Letter.

What is CUTX-101 and what condition is it intended to treat?

CUTX-101 is a formulation of copper histidinate intended to treat Menkes disease in pediatric patients, a rare disorder related to copper metabolism.

What financial terms apply to Cyprium and Fortress Biotech if CUTX-101 is approved?

Cyprium is eligible to receive royalties and up to $129 million in aggregate development and sales milestones related to CUTX-101, in addition to retaining potential Priority Review Voucher ownership.

Who is responsible for developing and commercializing CUTX-101?

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, Inc. in December 2023.

What is the significance of the Priority Review Voucher for Cyprium and FBIO?

Cyprium will retain ownership of any Priority Review Voucher that may be issued upon NDA approval of CUTX-101, which can have substantial value and is separate from the up to $129 million in milestone payments.

Why did the FDA previously issue a Complete Response Letter for CUTX-101?

The company disclosed that on October 1, 2025 the FDA issued a Complete Response Letter related to the NDA for CUTX-101, although specific deficiencies are not detailed in this content.