Moleculin Reports Independent Assessment Confirms No Cardiotoxicity of Annamycin in 90 Subjects 

Rhea-AI Summary

Moleculin (NASDAQ: MBRX) announced on January 13, 2026 that an independent expert reviewed cardiac data for 90 subjects treated with Annamycin and found no evidence of cardiotoxicity. The assessment covers data from five clinical trials in acute myeloid leukemia (AML) and soft tissue sarcoma (STS) across the US and EU, including serial 12-lead ECGs, transthoracic echocardiography with centralized global longitudinal strain (GLS) analysis, and central-lab troponin I/T measurements. The company reported that 65 of 90 subjects exceeded the FDA lifetime anthracycline limit of 550 mg/m2, with one subject exceeding 6500 mg/m2. Moleculin said the results support Annamycin's safety profile and its development as a next-generation anthracycline.

Positive

• Independent expert found no cardiotoxicity in 90 subjects
• Data spans five clinical trials in AML and STS
• 65 of 90 subjects exceeded FDA lifetime anthracycline limit (550 mg/m2)
• Cardiac monitoring included ECG, GLS echocardiography, and troponin central-lab assays
• Assessment covers subjects treated across the US and EU

Negative

• None.

News Market Reaction – MBRX

+5.93%

13 alerts

+5.93% News Effect

+7.0% Peak Tracked

-5.2% Trough Tracked

+$694K Valuation Impact

$12M Market Cap

0.4x Rel. Volume

On the day this news was published, MBRX gained 5.93%, reflecting a notable positive market reaction. Argus tracked a peak move of +7.0% during that session. Argus tracked a trough of -5.2% from its starting point during tracking. Our momentum scanner triggered 13 alerts that day, indicating notable trading interest and price volatility. This price movement added approximately $694K to the company's valuation, bringing the market cap to $12M at that time.

Data tracked by StockTitan Argus on the day of publication.

Key Figures

Subjects evaluated: 90 subjects Clinical trials: 5 trials High-exposure subjects: 65 of 90 subjects +4 more

7 metrics

Subjects evaluated 90 subjects Annamycin-treated subjects reviewed for cardiotoxicity across five trials

Clinical trials 5 trials Trials in AML and STS using Annamycin mono and combination therapy

High-exposure subjects 65 of 90 subjects Taken over FDA lifetime maximum anthracycline exposure

FDA lifetime maximum 550 mg/m2 FDA lifetime maximum cumulative anthracycline exposure reference

Highest exposure 6500 mg/m2 One subject exceeded this cumulative Annamycin dose without observed cardiotoxicity

Childhood cancers on anthracyclines 60% Childhood cancers currently treated with cardiotoxic anthracyclines

Long-term horizon 30 years Period after diagnosis when cardiac-related deaths can exceed recurrences

Market Reality Check

Price: $2.04 Vol: Volume 142,365 is below t...

low vol

$2.04 Last Close

Volume Volume 142,365 is below the 20-day average of 456,634, suggesting limited pre-news positioning. low

Technical Shares at $4.05 are trading below the $14.18 200-day MA and about 95.56% under the 52-week high.

Peers on Argus

MBRX gained 1.76% while peers were mixed: LPTX up 238.84%, INTS up 2.41%, and ot...

MBRX gained 1.76% while peers were mixed: LPTX up 238.84%, INTS up 2.41%, and others down, pointing to stock-specific factors rather than a coordinated biotech move.

Historical Context

5 past events · Latest: Dec 17 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Dec 17	Clinical trial update	Positive	-11.7%	Positive Phase 1 WP1066 data in pediatric malignant brain tumors.
Dec 10	Capital raise	Negative	-27.1%	Warrant exercises and issuance of new warrants for additional shares.
Dec 09	Clinical trial progress	Positive	-8.6%	MIRACLE Phase 2B/3 AML trial treatment progress and timelines.
Dec 08	Research collaboration	Positive	+0.1%	New Annamycin GBM collaboration and preclinical study plans.
Nov 26	Investor event	Neutral	-22.0%	Announcement of participation in a virtual investor presentation.

Pattern Detected

Recent history shows several negative price reactions to positive clinical and corporate updates, suggesting a tendency for good news to coincide with selling pressure.

Recent Company History

Over the last few months, Moleculin has reported multiple clinical and corporate milestones, including positive Phase 1 data for WP1066 on Dec 17, 2025 and advancement of the pivotal MIRACLE AML trial with 45 patients targeted in Q1 2026. It also executed warrant exercises for about $6.5M gross proceeds and announced a GBM collaboration for Annamycin. Despite these developments, several announcements were followed by double‑digit percentage declines, making today’s cardiotoxicity update another data point in an already eventful clinical trajectory.

Regulatory & Risk Context

Active S-3 Shelf

Shelf Active

Active S-3 Shelf Registration 2025-09-19

The company has an active S-3 shelf registration dated 2025-09-19 that is currently shown as not effective and with no recorded usage, indicating capacity for future registered offerings if made effective.

Market Pulse Summary

The stock moved +5.9% in the session following this news. A strong positive reaction aligns with the...

Analysis

The stock moved +5.9% in the session following this news. A strong positive reaction aligns with the clearly favorable safety signal, as an independent expert found no cardiotoxicity in 90 Annamycin-treated subjects, many above the 550 mg/m2 lifetime anthracycline limit. However, past positive updates on Dec 17 and Dec 9 saw declines of 11.73% and 8.55%, showing that enthusiasm has previously faded after news-driven spikes.

Key Terms

cardiotoxicity, anthracycline, acute myeloid leukemia, soft tissue sarcoma, +4 more

8 terms

cardiotoxicity medical

"independent assessment for the absence of cardiotoxicity in subjects treated"

Cardiotoxicity is damage to the heart caused by a drug, chemical or medical treatment that can weaken heart function, disrupt heartbeat or cause inflammation. It matters to investors because evidence of cardiotoxicity can halt or delay product approvals, trigger costly additional testing, recalls or legal risk, and reduce future revenue potential—similar to how rust in an engine can undermine a machine’s reliability and resale value.

anthracycline medical

"This next-generation anthracycline demonstrates safety and promising early activity"

An anthracycline is a type of powerful medicine used to treat cancer, working by killing or stopping the growth of cancer cells. Because these drugs can have significant side effects and influence healthcare costs, they are closely watched by investors, especially in the pharmaceutical and healthcare sectors. Their development and use can impact the financial performance of companies involved in cancer treatment.

acute myeloid leukemia medical

"five clinical trials treating acute myeloid leukemia (AML) and soft tissue sarcoma"

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.

soft tissue sarcoma medical

"five clinical trials treating acute myeloid leukemia (AML) and soft tissue sarcoma"

A soft tissue sarcoma is a type of cancer that starts in the body’s soft tissues — such as muscles, fat, nerves, blood vessels or connective tissue — rather than in organs or bones. For investors, it matters because treatments for these cancers drive drug development, clinical trial results and regulatory decisions; a successful therapy can create a meaningful commercial market while trial failures or safety issues can affect a company’s valuation and prospects.

cytarabine medical

"Annamycin as a monotherapy and in combination with cytarabine and across multiple sites"

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.

transthoracic echocardiography medical

"transthoracic echocardiography with centralized global longitudinal strain (GLS) analysis"

Transthoracic echocardiography is a noninvasive heart imaging test that uses ultrasound waved passed through the chest to create moving pictures of the heart’s structure and pumping function, like a sonar camera for the heart. Investors care because it’s widely used in clinical trials and routine care to measure safety and effectiveness of cardiac drugs and devices, influence trial endpoints, and affect regulatory and market outcomes.

global longitudinal strain medical

"echocardiography with centralized global longitudinal strain (GLS) analysis"

Global longitudinal strain is a measurement of how much the heart’s main pumping muscle shortens along its length with each beat, typically obtained from a heart ultrasound. Think of it like measuring how far a rubber band shrinks when released; it's a sensitive early indicator of heart muscle performance and treatment effect, so changes can influence clinical trial results, regulatory decisions and the market value of companies tied to cardiac therapies or devices.

cardiomyopathy medical

"can lead to cardiomyopathy, clinical heart failure, the need for a heart transplant"

A condition that weakens or stiffens the heart muscle, reducing its ability to pump blood effectively; think of the heart as an engine that becomes less powerful or less flexible. For investors, cardiomyopathy matters because it can drive demand for medical treatments, affect healthcare costs, influence the value of companies developing drugs or devices, and trigger regulatory or insurance impacts that change revenues and risks across the healthcare sector.

AI-generated analysis. Not financial advice.

– Annamycin consistently demonstrates no evidence of cardiotoxicity across five clinical trials

– This next-generation anthracycline demonstrates safety and promising early activity in treating multiple oncology indications

HOUSTON, Jan. 13, 2026 (GLOBE NEWSWIRE) -- Moleculin Biotech, Inc., (Nasdaq: MBRX) (“Moleculin” or the “Company”), announced it has received a new independent assessment for the absence of cardiotoxicity in subjects treated with Annamycin, bringing the total number of Annamycin treated subjects reviewed by its independent expert to 90. Data from the most recently completed clinical trials’ subjects were made available to an expert in chemotherapy who is affiliated with a leading cancer research institute in assessing cardiotoxicity. After review of certain data, the independent expert concluded that there was no evidence of cardiotoxicity. This data is across five clinical trials treating acute myeloid leukemia (AML) and soft tissue sarcoma (STS) with Annamycin as a monotherapy and in combination with cytarabine and across multiple sites in the United States (US) and the European Union (EU). Most of these subjects were treated above the recommended lifetime maximum for other anthracyclines.

The data made available to the expert included, but was not limited to, data from serial 12-lead ECGs, transthoracic echocardiography with centralized global longitudinal strain (GLS) analysis, and cardiac biomarker (troponins I and T) concentration measurements by a central lab using validated assays. Cardiac health biomarkers such as blood troponin levels are considered an indicator of potential long-term heart damage.

“As we closely approach almost 100 subjects that have received Annamycin (also known by the name “naxtarubicin”) which have been reviewed by our expert, we continue to be encouraged by the potential of Annamycin. This additional independent report of additional datasets provides further validation of the absence of cardiotoxicity,” commented Walter Klemp, Chairman and Chief Executive Officer of Moleculin. “Annamycin continues to demonstrate an absence of cardiotoxicity, even in subjects who have received far more than the lifetime maximum cumulative anthracycline exposure established by the US Food and Drug Administration (FDA). In fact, 65 of the 90 subjects evaluated have been taken over the FDA’s lifetime maximum of 550 mg/m2 and with one of them being taken over 6500 mg/m2. Our growing body of positive data for Annamycin continues to bolster our confidence in our belief that Annamycin is truly a ‘next generation’ anthracycline, especially in light of the growing efficacy data that we have previously reported in the treatment of AML and STS. We remain focused on advancing our Annamycin development programs and ultimately, addressing the medical unmet needs of people with difficult to treat cancers.”

“It is important to understand that nearly half of all cancers and 60% of childhood cancers are currently treated with cardiotoxic anthracyclines that result in permanent damage to the heart. To quote one study: ‘Some commonly used cancer drugs, such as the anthracyclines, are known to be cardiotoxic. Left undetected and untreated, this cardiotoxicity is progressive and persistent and can lead to cardiomyopathy, clinical heart failure, the need for a heart transplant, or death. In fact, 30 years after diagnosis, the number of cardiac-related deaths among survivors exceeds the number caused by cancer recurrence (emphasis added).’ We believe Annamycin has the potential to become the first ever non-cardiotoxic anthracycline. Coupled with its observed ability in a wide range of tumor animal models to avoid cross-resistance with existing anthracyclines and to demonstrate equal or greater efficacy, we believe the market opportunity for Annamycin is potentially enormous. We are looking forward to adding to this dataset and completing long-term cardiac follow-up with active subjects in our current trials.”

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”) and, 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, statements regarding the continued recruitment, treatment, and receipt of the unblinded data for the first 45 subjects of the MIRACLE clinical trial as described. 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 did Moleculin announce about Annamycin cardiotoxicity on January 13, 2026?

An independent expert reviewed data for 90 subjects and concluded there was no evidence of cardiotoxicity.

Which cancers and trial types were included in the Annamycin cardiotoxicity assessment (MBRX)?

The assessment covered five clinical trials treating AML and soft tissue sarcoma (STS) as monotherapy and combined with cytarabine.

What cardiac tests were reviewed in the Annamycin safety assessment for MBRX?

Reviewed data included serial 12-lead ECGs, transthoracic echocardiography with GLS, and troponin I/T measurements by a central lab.

How many Annamycin-treated subjects exceeded the FDA lifetime anthracycline limit in the MBRX report?

65 of 90 subjects were reported to have exceeded the FDA lifetime maximum of 550 mg/m2, with one subject exceeding 6500 mg/m2.

Does the MBRX announcement confirm long-term cardiac outcomes for Annamycin?

The announcement reports an independent expert found no evidence of cardiotoxicity in available data but notes ongoing long-term cardiac follow-up of active subjects.