MBRX Announces Global Recruitment Progress in Pivotal Annamycin + Ara-C Study

Rhea-AI Filing Summary

Moleculin Biotech announced updates to its pivotal Phase 2B/3 trial ("MIRACLE") evaluating Annamycin combined with cytarabine ("AnnAraC") for adults with relapsed or refractory acute myeloid leukemia (R/R AML). The company reported active site status and recruitment updates for the multi-center, randomized, double-blind, placebo-controlled, adaptive-design study. The MIRACLE trial is described as a global approval trial with sites in the U.S., Europe and the Middle East. A press release providing these trial updates is attached to the report as Exhibit 99.1 and is furnished with the filing.

Positive

• Operational progress reported with active site status and recruitment updates for the pivotal trial
• Robust trial design: randomized, double-blind, placebo-controlled, adaptive Phase 2B/3 intended as a global approval study
• Global footprint explicitly includes sites in the U.S., Europe and the Middle East

Negative

• No enrollment numbers, timelines, or interim efficacy/safety data provided
• No regulatory submission timing or specific primary endpoint information disclosed
• Financial impact is unspecified; the filing contains no financials or material commercial metrics

Insights

Clinical Development Analyst

TL;DR: Company reports operational progress in a global pivotal Phase 2B/3 adaptive trial of Annamycin with Ara-C for R/R AML.

The filing provides an operational update confirming active site status and recruitment activity for a multi-center, randomized, double-blind, placebo-controlled adaptive-design study. This design and global footprint (U.S., Europe, Middle East) are appropriate for seeking broad regulatory approvals if the trial meets endpoints. The disclosure, however, contains no enrollment figures, timelines, interim results, or safety/efficacy data, limiting near-term interpretability of clinical risk or probability of success.

Regulatory Affairs Specialist

TL;DR: The trial's global, adaptive Phase 2B/3 structure supports regulatory engagement but the filing supplies only procedural updates.

An adaptive, randomized, placebo-controlled pivotal study is aligned with regulatory expectations for a global approval pathway. Inclusion of multiple regions suggests intent to support submissions in several jurisdictions. The report merely references site activation and recruitment updates via an attached press release; there is no regulatory filing, endpoint description, or timeline disclosed here to assess regulatory milestones or filing strategy.

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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): September 9, 2025

MOLECULIN BIOTECH, INC.

(Exact Name of Registrant as Specified in its Charter)

Delaware	001-37758	47-4671997
(State or Other Jurisdiction of Incorporation or Organization)	(Commission File No.)	(I.R.S. Employer Identification No.)

5300 Memorial Drive, Suite 950, Houston, TX 77007

(Address of principal executive offices and zip code)

(713) 300-5160

(Registrant’s telephone number, including area code)

(Former name or former address, if changed from last report)

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 (see General Instruction A.2. below):

☐	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
☐	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
☐	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
☐	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-14(c))

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. ☐

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, par value $.001 per share	MBRX	The NASDAQ Stock Market LLC

Item 7.01 Regulation FD Disclosure

On September 9, 2025, Moleculin Biotech, Inc. (the “Company”), issued a press release which announced updates to its active site status and recruitment for its pivotal Phase 2B/3, multi-center, randomized, double-blind, placebo-controlled, adaptive design study of Annamycin in combination with cytarabine (also known as “Ara-C” and for which the combination of Annamycin and Ara-C is referred to as “AnnAraC”) for the treatment of adult patients with acute myeloid leukemia (AML) who are refractory to or relapsed (R/R) after induction therapy (R/R AML). This Phase 3 “MIRACLE” trial (derived from Moleculin R/R AML AnnAraC Clinical Evaluation) is a global approval trial, including sites in the US, Europe and the Middle East.

A copy of the press release is attached to this report as Exhibit 99.1 and is incorporated by reference herein.

The information contained in Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1, is being furnished and shall not be “filed” for the purpose of the Securities Exchange Act of 1934, as amended (“Exchange Act”), nor shall it be incorporated by reference in any filing under the Exchange Act or the Securities Act of 1933, as amended (“Securities Act”), unless specifically identified therein as being incorporated by reference.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No. Description

99.1 Press Releasedated September 9, 2025

104 Cover page Interactive Data File (formatted as Inline XBRL document)

SIGNATURE

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

	MOLECULIN BIOTECH, INC.
	Date:	September 9, 2025
	By:	/s/ Jonathan P. Foster
		Jonathan P. Foster

FAQ

What did Moleculin Biotech (MBRX) report in this 8-K?

The company furnished a press release reporting active site status and recruitment updates for its pivotal Phase 2B/3 MIRACLE trial of Annamycin plus cytarabine for R/R AML.

What is the design of the MIRACLE trial mentioned by MBRX?

The MIRACLE trial is a multi-center, randomized, double-blind, placebo-controlled, adaptive Phase 2B/3 study intended as a global approval trial.

Which regions are included in the MIRACLE trial?

The filing states the trial includes sites in the United States, Europe and the Middle East.

Does the filing include clinical results or enrollment numbers?

No. The filing references site status and recruitment updates but does not provide enrollment figures, efficacy, safety, or timeline details.

Where can I find the full press release referenced in the 8-K?

The press release is attached to the report as Exhibit 99.1 and is incorporated by reference into the filing.