Moleculin Hits 45 Subject Enrollment Milestone, Triggering Final Countdown to Mid-2026 MIRACLE Trial Data Readout

Rhea-AI Summary

Moleculin (Nasdaq: MBRX) announced enrollment of the 45th subject in its global Phase 2B/3 MIRACLE trial of Annamycin plus cytarabine (AnnAraC) for relapsed/refractory AML, triggering preparations for an interim unblinding expected mid-2026. Preliminary blinded results among the first 30 patients showed a 40% composite complete remission rate (30% CR; 10% CR with partial recovery), with ~35% having failed prior venetoclax therapy. The protocol calls for early unblinding at 45 subjects and full Part A completion at 90 subjects, supporting dose selection and a potential accelerated approval pathway based on the CR endpoint.

Positive

• 45 subjects enrolled, enabling planned interim unblinding mid-2026
• 40% composite CR rate reported in preliminary blinded data (first 30 patients)
• Multinational trial across eight countries, showing consistent activity
• Adaptive Phase 2B/3 design supports integrated registration pathway and dose optimization

Negative

• Interim dataset is blinded and preliminary, requiring full unblinding for confirmatory assessment
• Part A completion requires enrollment to 90 subjects, delaying definitive Phase 3 start until Q3 2026
• Control arm comprises only 15 of 45 subjects in initial unblinding, limiting early comparative power

Key Figures

Enrollment milestone: 45 subjects Target enrollment Part A: 90 subjects Interim AnnAraC patients: ≈30 patients +5 more

8 metrics

Enrollment milestone 45 subjects Triggers interim unblinding in MIRACLE pivotal Phase 2B/3 trial

Target enrollment Part A 90 subjects Completion of Part A of MIRACLE, expected Q3 2026

Interim AnnAraC patients ≈30 patients Expected AnnAraC-treated group at first 45-subject unblinding

Interim control patients 15 patients Control arm receiving cytarabine plus placebo at first unblinding

Preliminary CRc rate 40% Blinded composite remission in first 30 MIRACLE patients

Complete remission 30% CR component of CRc in first 30 MIRACLE patients

CRh component 10% CR with partial hematologic recovery in first 30 patients

Prior venetoclax failure ≈35% of subjects Share of MIRACLE patients who failed venetoclax-based therapies

Market Reality Check

Price: $2.06 Vol: Volume 78,510 is below th...

low vol

$2.06 Last Close

Volume Volume 78,510 is below the 20-day average of 146,056 (relative volume 0.54). low

Technical Price 2.06 is trading below the 200-day MA of 9.4, indicating prior downtrend.

Historical Context

5 past events · Latest: Mar 19 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Mar 19	Earnings and trial update	Positive	-1.0%	Full-year 2025 results and confirmation of 40% blinded CRc, runway into Q3 2026.
Mar 17	Conference participation	Neutral	+5.4%	Announcement of presentation at 38th Annual ROTH Conference with senior management.
Mar 11	CEO MIRACLE update	Positive	+3.0%	CEO Corner segment detailing MIRACLE study progress and upcoming 45-patient unblinding.
Feb 19	Warrant exercise financing	Negative	-44.3%	Immediate warrant exercises raising about $8.3M and issuing new warrants.
Feb 18	MIRACLE efficacy signal	Positive	+5.5%	Report of 40% preliminary blinded CRc (30% CR, 10% CRh) in first 30 subjects.

Pattern Detected

Recent MIRACLE-related updates have often coincided with positive price reactions, while financing activity drew a sharp negative response.

Recent Company History

Over recent months, Moleculin has focused investors on its pivotal MIRACLE trial. Updates on blinded CRc data and trial design on Feb 18, 2026 and a CEO segment on Mar 11, 2026 both preceded positive one-day moves. Participation in the Mar 24, 2026 ROTH conference also aligned with gains. By contrast, the Feb 19, 2026 warrant exercise financing news coincided with a -44.28% move. The latest earnings on Mar 19, 2026 reiterated the 40% CRc and runway into Q3 2026 but saw a modest decline.

Regulatory & Risk Context

Active S-3 Shelf · $35.7 million

Shelf Active

Active S-3 Shelf Registration 2025-09-19

$35.7 million registered capacity

An effective S-3 shelf filed on 2025-09-19 registers up to 64,864,864 warrant-related resale shares, with potential company proceeds of $35.7 million only upon cash exercise of these warrants. The company does not receive proceeds from resale by selling stockholders.

Market Pulse Summary

This announcement marks completion of dosing for the 45th subject in the pivotal MIRACLE Phase 2B/3 ...

Analysis

This announcement marks completion of dosing for the 45th subject in the pivotal MIRACLE Phase 2B/3 trial, triggering preparations for a mid-2026 interim unblinding. Early blinded data showed a 40% composite remission rate in the first 30 patients, including high-risk, venetoclax-exposed subjects across eight countries. Investors may track enrollment toward 90 subjects, forthcoming unblinding milestones, and how efficacy, safety, and dose selection shape the Phase 3 path and any accelerated approval discussions.

Key Terms

phase 2b/3, acute myeloid leukemia, relapsed or refractory, cytarabine, +3 more

7 terms

phase 2b/3 medical

"pivotal Phase 2B/3 MIRACLE trial evaluating Annamycin in combination"

A phase 2b/3 trial is a combined late-stage clinical study that first refines the best dose and measures how well a treatment works (phase 2b) then expands to a larger, definitive test of safety and effectiveness needed for regulatory approval (phase 3). For investors, results from a phase 2b/3 act like a dress rehearsal that turns into opening night: positive, well-controlled outcomes substantially raise the chance of approval and future sales, while failures can sharply reduce a drug’s value.

acute myeloid leukemia medical

"for the treatment of adult subjects with relapsed or refractory acute myeloid leukemia"

A fast‑moving blood cancer that starts in the bone marrow and crowd out healthy blood cell production, leaving the body short of normal red cells, white cells and platelets. It matters to investors because the disease creates urgent medical need, drives demand for new diagnostics and treatments, and so clinical trial results, regulatory decisions and drug pricing can rapidly change the commercial prospects and valuation of companies working on therapies.

relapsed or refractory medical

"for the treatment of adult subjects with relapsed or refractory acute myeloid leukemia"

"Relapsed or refractory" describes a situation where a disease, such as an illness or condition, returns after treatment or does not respond to initial treatment efforts. For investors, this indicates ongoing challenges or setbacks in managing the disease, which can affect the success of related treatments or therapies and impact the potential value of associated companies or products. Understanding this helps gauge the stability and future prospects of medical developments or healthcare investments.

cytarabine medical

"Annamycin in combination with cytarabine (AnnAraC) for the treatment"

A chemotherapy medicine used mainly to treat certain blood cancers, especially types of leukemia; it works by disrupting how fast-dividing cancer cells copy their genetic material, which slows or stops tumor growth. Investors watch cytarabine because clinical trial results, regulatory approvals, manufacturing quality, supply or pricing changes, and patent status can directly affect sales, development costs and the valuation of drugmakers or suppliers—similar to how a key component's availability can make or break a factory's output.

placebo medical

"control arm receiving cytarabine plus placebo"

A placebo is an inactive pill, injection or procedure that looks and feels like the real treatment but contains no therapeutic ingredient, often called a sugar pill. Investors care because comparing a drug to a placebo reveals whether observed benefits come from the medicine itself or from expectation; clear superiority over placebo reduces regulatory and commercial risk, much like a blind taste test proves a new recipe really tastes better.

project optimus regulatory

"in alignment with regulatory guidance, including FDA Project Optimus principles"

Project Optimus is a regulatory initiative from the U.S. Food and Drug Administration aimed at changing how cancer drugs are dosed during development, encouraging careful testing to find the best effective dose rather than simply the highest tolerated one. For investors this matters because it can change clinical trial plans, add time or cost, affect safety and labeling outcomes, and ultimately influence a drug’s commercial success—like tuning volume to a clear level instead of always turning it up to the maximum.

accelerated approval regulatory

"on track toward a potential accelerated approval pathway based solely on the Complete Remission"

Accelerated approval is a process that allows new medical treatments to be approved more quickly than usual if they address serious or life-threatening conditions and show promising early results. For investors, it signals that a treatment may reach the market sooner, potentially boosting a company's prospects, but it also involves some uncertainty since full evidence of effectiveness is still being gathered.

AI-generated analysis. Not financial advice.

• First Interim Unblinding of Pivotal AML Trial Now Imminent — Potentially the Most Important Data Moment in Company History
  
  
• Early Blinded Results Show 40% Remission Rate Across Difficult-to-Treat Patient Population
  
  
• Enrollment Accelerating Toward 90 Subject Threshold as Phase 3 Pathway Takes Shape
  
  

HOUSTON, March 23, 2026 (GLOBE NEWSWIRE) -- Moleculin Biotech, Inc., (Nasdaq: MBRX) (“Moleculin” or the “Company”), today announced that the 45th subject has been enrolled in its pivotal Phase 2B/3 MIRACLE trial evaluating Annamycin in combination with cytarabine (AnnAraC) for the treatment of adult subjects with relapsed or refractory acute myeloid leukemia (R/R AML). This milestone triggers the final phase of preparation for the trial’s interim 45 subject data unblinding, which remains on track for mid-2026 and represents a potentially defining inflection point for the Company.

“We believe this upcoming data readout represents the most important milestone in our history to date,” said Walter Klemp, Chairman and CEO of Moleculin. “This is a critical achievement for Moleculin and, more importantly, for patients facing relapsed or refractory AML. Reaching the 45 subject mark brings us to the threshold of our first meaningful look at MIRACLE data. Based on what we believe to be encouraging blinded results announced in February, we believe we are building real momentum toward what could be a transformative outcome. Our Phase 2 AML MB-106 clinical trial generated greater efficacy than any drug ever approved for relapsed or refractory AML, and it contributed to the more than 100 patients treated to date without any associated cardiotoxicity. What remains now is to demonstrate that a larger Phase 3 trial can produce results that will support new drug approval. The upcoming unblinding of the first 45 subjects should be a strong indicator of that potential. A true next-generation anthracycline has long been sought by medical science and would rightly be considered a gamechanger, not just for AML but for a wide range of cancers. We now appear to be on the threshold of finding out whether this can become a reality.”

Moleculin Biotech continues to advance toward a defining milestone with its ongoing MIRACLE trial, a global, adaptive Phase 2B/3 study designed to evaluate AnnAraC across eight countries to date. The trial protocol provides for early unblinding of data after the first 45 subjects complete treatment, which is expected to yield an initial dataset of approximately 30 patients treated with AnnAraC (at two different dose levels) and 15 patients in the control arm receiving cytarabine plus placebo. This upcoming interim readout is anticipated to provide critical insights into efficacy, safety, and dose optimization as the study progresses toward its Phase 3 portion. Enrollment continues in parallel with the 45^th subject unblinding as the Company advances to 90 total subjects thereby concluding Part A of MIRACLE, expected in Q3 2026, with the complete unblinding of Part A thereafter.

Encouraging early signals have already emerged from this difficult-to-treat patient population. In February 2026, Moleculin reported a preliminary blinded composite complete remission rate of 40% among the first 30 patients enrolled in the MIRACLE trial, consisting of 30% complete remission and 10% complete remission with partial hematologic recovery. These findings are particularly notable given that approximately 35% of subjects had previously failed venetoclax-based therapies, and many exhibited adverse genetic markers typically associated with poor outcomes. Additionally, the multinational nature of the trial underscores consistent activity across diverse clinical settings. Even with the inclusion of the control arm, these preliminary blinded aggregate outcomes compare favorably to historical remission rates associated with cytarabine alone in relapsed or refractory acute myeloid leukemia.

The MIRACLE trial’s adaptive design is intended to support a streamlined global registration pathway by integrating data from its Phase 2B portion into the planned Phase 3 portion, in alignment with regulatory guidance, including FDA Project Optimus principles. Following the interim readout, enrollment is expected to continue toward 90 patients to enable a second unblinding, with the Phase 3 portion of the study commencing once the optimum dose is determined. The program remains on track toward a potential accelerated approval pathway based solely on the Complete Remission primary endpoint.

Progress in the MIRACLE trial also reflects broader momentum across Moleculin’s oncology pipeline, which includes ongoing and planned studies targeting pancreatic cancer, brain tumors, and soft tissue sarcoma. With dosing of the 45th subject now complete, the Company is entering a catalyst-rich period leading up to the anticipated mid-2026 interim data readout, a milestone that could significantly influence the future development of Annamycin in the treatment of acute myeloid leukemia.

For additional information on the MIRACLE trial, please visit ClinicalTrials.gov and reference Identifier: NCT06788756.

About Moleculin Biotech, Inc.

Moleculin Biotech, Inc. is a Phase 3 clinical stage pharmaceutical company advancing a pipeline of therapeutic candidates addressing hard-to-treat tumors and viruses. The Company’s lead program, Annamycin (also known as naxtarubicin), is a next-generation highly efficacious and well tolerated anthracycline designed to avoid multidrug resistance mechanisms and to lack the cardiotoxicity common with currently prescribed anthracyclines. Annamycin is currently in development for the treatment of relapsed or refractory acute myeloid leukemia (AML) and soft tissue sarcoma (STS) lung metastases.

The Company has begun the MIRACLE (Moleculin R/R AML AnnAraC Clinical Evaluation) Trial (MB-108), a pivotal, adaptive design Phase 3 trial evaluating Annamycin in combination with cytarabine, together referred to as AnnAraC (the combination of Annamycin and cytarabine, also referred to as “Ara-C”) for the treatment of relapsed or refractory acute myeloid leukemia. Following a successful Phase 1B/2 study (MB-106), with input from the FDA, the Company believes it has substantially de-risked the development pathway towards a potential approval for Annamycin for the treatment of AML. This study remains subject to appropriate future filings with potential additional feedback from the FDA and their foreign equivalents.

Additionally, the Company is developing WP1066, an Immune/Transcription Modulator capable of inhibiting p-STAT3 and other oncogenic transcription factors while also stimulating a natural immune response, targeting brain tumors, pancreatic and other cancers. Moleculin also has in its pipeline a portfolio of antimetabolites, including WP1122 for the potential treatment of pathogenic viruses, as well as certain cancer indications. 

For more information about the Company, please visit www.moleculin.com and connect on X, LinkedIn and Facebook.

Forward-Looking Statements
Some of the statements in this release are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, Section 21E of the Securities Exchange Act of 1934 and the Private Securities Litigation Reform Act of 1995, which involve risks and uncertainties. Forward-looking statements in this press release include, without limitation, the expected timing and results of the 45-subject interim data unblinding in the MIRACLE trial, the anticipated clinical milestones set forth above, and the potential efficacy and safety of Annamycin and AnnAraC in R/R AML and other indications. Moleculin will require significant additional financing, for which the Company has no commitments, in order to conduct its clinical trials as described in this press release, and the milestones described in this press release assume the Company’s ability to secure such financing on a timely basis. Although Moleculin believes that the expectations reflected in such forward-looking statements are reasonable as of the date made, expectations may prove to have been materially different from the results expressed or implied by such forward-looking statements. The Company relies on the reports of its expert with regard to the absence of cardiotoxicity. The dataset referenced in this press release is subject to the review of the data from future subjects in its current and future clinical trials and long-term follow-up with subjects in its current trials. Moleculin has attempted to identify forward-looking statements by terminology including ‘believes,’ ‘estimates,’ ‘anticipates,’ ‘expects,’ ‘plans,’ ‘projects,’ ‘intends,’ ‘potential,’ ‘may,’ ‘could,’ ‘might,’ ‘will,’ ‘should,’ ‘approximately’ or other words that convey uncertainty of future events or outcomes to identify these forward-looking statements. These statements are only predictions and involve known and unknown risks, uncertainties, and other factors, including those discussed under Item 1A. “Risk Factors” in our most recently filed Form 10-K filed with the Securities and Exchange Commission (SEC) and updated from time to time in our Form 10-Q filings and in our other public filings with the SEC. Any forward-looking statements contained in this release speak only as of its date. We undertake no obligation to update any forward-looking statements contained in this release to reflect events or circumstances occurring after its date or to reflect the occurrence of unanticipated events.

Investor Contact:
JTC Team, LLC
Jenene Thomas
(908) 824-0775
MBRX@jtcir.com

FAQ

What does Moleculin's 45-subject enrollment mean for MBRX timeline?

It triggers final preparation for the interim unblinding expected mid-2026 and accelerates milestone timing. According to the company, reaching 45 subjects enables an early look at efficacy, safety, and dose selection ahead of Part A completion at 90 subjects in Q3 2026.

How significant is the reported 40% remission rate for MBRX's MIRACLE trial?

A 40% composite complete remission rate is an encouraging early signal but remains preliminary and blinded. According to the company, this rate comes from the first 30 enrolled patients and will be reassessed at the planned 45-subject unblinding.

When will MBRX unblind MIRACLE interim data and what will it show?

The interim unblinding is expected mid-2026 and should provide initial efficacy and safety insights. According to the company, the 45-subject readout will include roughly 30 AnnAraC-treated patients and 15 control patients to inform dose optimization.

How does the MIRACLE trial design affect MBRX's approval pathway for Annamycin?

The adaptive Phase 2B/3 design aims to integrate Phase 2B data into Phase 3 to streamline registration. According to the company, this supports a potential accelerated approval pathway based on the Complete Remission primary endpoint.

What enrollment milestone remains before Part A of MIRACLE completes for MBRX?

Part A completes at 90 total subjects, with a second unblinding planned thereafter and Phase 3 start after dose selection. According to the company, reaching 90 patients is expected in Q3 2026, enabling complete unblinding of Part A.

Does prior venetoclax failure affect MIRACLE early results for MBRX?

Approximately 35% of early MIRACLE subjects previously failed venetoclax-based therapies, yet blinded remission signals persisted. According to the company, this makes the preliminary 40% composite CR notable in a difficult-to-treat population.