Moleculin Receives Positive FDA Feedback on Pediatric Study Plan for Annamycin in Children with R/R AML

Rhea-AI Summary

Moleculin Biotech (NASDAQ: MBRX) has received positive FDA feedback on its Initial Pediatric Study Plan (iPSP) for Annamycin in treating children with relapsed/refractory acute myeloid leukemia (R/R AML). The FDA agreed to a single pediatric approval study of AnnAraC (Annamycin + Cytarabine combination) and recommended including patients as young as 6 months old. Notably, Annamycin has shown no cardiotoxicity in 84 adult patients treated to date, addressing a significant concern as about 60% of children with cancer are treated with potentially cardiotoxic anthracyclines. The company plans to initiate the pediatric trial in H2 2027. Meanwhile, Moleculin's pivotal Phase 3 MIRACLE trial for adult R/R AML patients is ongoing with initial data expected in H2 2025. Annamycin has received Fast Track Status and Orphan Drug Designations from both FDA and EMA.

Positive

• No cardiotoxicity observed in 84 adult patients treated with Annamycin to date
• FDA agrees to a single pediatric approval study, streamlining the approval process
• FDA allows inclusion of younger patients (6 months+) than initially proposed
• FDA permits pediatric trial initiation before full adult trial data completion
• Multiple regulatory advantages with Fast Track Status and Orphan Drug Designations from FDA and EMA

Negative

• Pediatric clinical study won't begin until second half of 2027
• Initial data from adult MIRACLE trial not available until second half of 2025

Insights

Oncology Clinical Development Expert

Moleculin secures FDA backing for pediatric AML trial with Annamycin, expanding potential market while adult Phase 3 trial progresses.

Moleculin's announcement represents a significant regulatory advancement for Annamycin, their novel anthracycline candidate designed to eliminate the cardiotoxicity associated with standard anthracyclines. The FDA's feedback on their Initial Pediatric Study Plan (iPSP) is notably more favorable than expected, allowing for inclusion of patients as young as 6 months (younger than Moleculin had initially proposed) in their planned pediatric R/R AML trial.

The FDA has agreed to a streamlined development approach through a single pediatric approval study evaluating Annamycin in combination with cytarabine (AnnAraC). This regulatory efficiency could significantly accelerate the path to potential pediatric approval. Furthermore, the agency indicated that Moleculin can initiate the pediatric trial before completing the full two-year follow-up from their adult trial - a meaningful regulatory accommodation.

Particularly noteworthy is the FDA's confirmation that efficacy data could be extrapolated from adults if drug concentration exposure and safety profiles are comparable between populations. This creates a more efficient development pathway by potentially reducing the burden of demonstrating efficacy separately in children.

The company has emphasized Annamycin's cardiotoxicity profile, with an independent expert review showing no cardiotoxicity in 84 adult patients treated to date. This is clinically significant since approximately 60% of children with cancer are treated with anthracyclines that carry high cardiac damage risk.

While the pediatric trial is planned for the second half of 2027 (still distant), investors should focus on the ongoing pivotal Phase 3 MIRACLE trial in adults with R/R AML, which has begun enrollment with initial data expected later in 2025. The drug has secured Fast Track Status and Orphan Drug Designation from FDA, providing regulatory advantages that could accelerate development timelines.

Annamycin aims to eliminate cardiotoxicity associated with anthracyclines used to treat about 60% of all children with cancer 

FDA recommends inclusion of patients as young as 6 months – younger than Moleculin had proposed – to be allowed in the pediatric clinical study

Enrollment and dosing are ongoing in pivotal, adaptive design Phase 3 MIRACLE trial of Annamycin in adult patients with R/R AML; Initial data readout is on track for the second half of 2025

HOUSTON, June 18, 2025 (GLOBE NEWSWIRE) -- Moleculin Biotech, Inc., (Nasdaq: MBRX) (“Moleculin” or the “Company”), a late-stage pharmaceutical company with a broad portfolio of drug candidates targeting hard-to-treat cancers and viral infections, today announced it has received a written response from the Office of Oncologic Diseases - Pediatric Oncology, of the U.S. Food and Drug Administration (FDA) regarding the Company’s Initial Pediatric Study Plan (iPSP), which was submitted after a June 2024 end-of-phase 1/2 meeting. The FDA has agreed to a single pediatric approval study in which Annamycin (also known as naxtarubicin) in combination with Cytarabine (also known as “Ara-C” and for which the combination of Annamycin and Ara-C is referred to as “AnnAraC”) will be evaluated as second line therapy in pediatric patients with relapsed/refractory acute myeloid leukemia (R/R AML), a form of cancer.

“We continue to be encouraged by the potential of Annamycin to change the game when it comes to the most prevalent cancer therapies in use today. This is particularly important in pediatric oncology, where about 60% of children with cancer are treated with anthracyclines that present a high risk of causing heart damage. An independent expert’s review of study data has shown no cardiotoxicity to date in 84 adult patients treated with Annamycin, which is why we’re excited about moving forward in young children with cancer. Receiving this written feedback from FDA is a crucial step in the development of Annamycin for pediatric use and provides us with helpful insight as we continue to prepare for the launch of a pediatric trial, planned for the second half of 2027,” said Walter Klemp, Chairman and CEO of Moleculin. “As our team works to address and implement FDA’s feedback on our iPSP, we remain focused on the successful execution of our ongoing MIRACLE trial of AnnAraC in adult patients with R/R AML and look forward to initial data from that trial later this year.”

As part of the iPSP, Moleculin proposed a single-arm study evaluating pharmacokinetics (PK), efficacy, and safety of AnnAraC in patients between 2 and 16 years of age. The FDA response calls for including patients from 6 months of age and older, with no minimum number of patients between 6 months and 2 years old. FDA also clarified that drug concentration exposure and safety profile that are comparable would allow extrapolation from efficacy in adults. Importantly, FDA said Moleculin would be able to start the pediatric trial before having the full two years of follow-up data from the adult trial.

Moleculin is in the process of updating its iPSP to incorporate FDA’s recommendations and intends to submit the revised plan to FDA later this quarter. Moleculin expects to initiate pediatric clinical study in the second half of 2027.

The Company is currently evaluating AnnAraC for the treatment of adult patients with R/R AML in the pivotal, adaptive Phase 3 MIRACLE trial (MB-108). This “MIRACLE” trial (derived from Moleculin R/R AML AnnAraC Clinical Evaluation) is a global trial, including sites in the US, Europe and the Middle East. Patient dosing has commenced, and the initial data readout is on track for the second half of 2025. For more information about the MIRACLE trial, visit clinicaltrials.gov and reference identifier NCT06788756

FDA has granted Annamycin Fast Track Status and Orphan Drug Designation for treating relapsed or refractory acute myeloid leukemia, and an additional Orphan Drug Designation for treating soft tissue sarcoma. The European Medicines Agency (EMA) has also granted Orphan Drug Designation for the treatment of relapsed or refractory acute myeloid leukemia.

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, is a next-generation highly efficacious and well tolerated anthracycline designed to avoid multidrug resistance mechanisms and to eliminate the cardiotoxicity common with currently prescribed anthracyclines. The non-proprietary name for Annamycin is naxtarubicin. Annamycin is currently in development for the treatment of relapsed or refractory acute myeloid leukemia (AML) and soft tissue sarcoma (STS) lung metastases. Company discussions regarding Annamycin’s lack of cardiotoxicity reflect the following: 1) Annamycin was designed to be non-cardiotoxic; 2) Preclinical studies have demonstrated Annamycin lacks cardiotoxicity as compared to a currently prescribed anthracycline; and, 3) An independent expert’s conclusions after analyzing the data from 84 subjects treated with Annamycin in five clinical studies conducted in the US and in Europe.

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 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 toward a potential approval for Annamycin for the treatment of AML. This study is subject to appropriate future filings with potential additional feedback from the FDA and foreign regulators.

Moleculin is also 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. The Company also is developing 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 timing of the initiation of the pediatric clinical study. 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. 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 is the significance of FDA's feedback on Moleculin's pediatric study plan for Annamycin?

FDA's feedback allows for a single pediatric approval study and includes younger patients (6 months+), while also permitting trial initiation before complete adult trial data, streamlining the development process.

How does Annamycin (MBRX) address cardiotoxicity concerns in cancer treatment?

Annamycin has shown no cardiotoxicity in 84 adult patients treated to date, potentially offering a safer alternative to current anthracyclines that risk heart damage in 60% of children with cancer.

When will Moleculin (MBRX) begin its pediatric clinical trial for Annamycin?

Moleculin plans to initiate the pediatric clinical trial in the second half of 2027.

What is the status of Moleculin's Phase 3 MIRACLE trial for adult R/R AML?

The Phase 3 MIRACLE trial is currently enrolling and dosing patients globally, with initial data readout expected in the second half of 2025.

What regulatory designations has Annamycin received from FDA and EMA?

Annamycin has received Fast Track Status and Orphan Drug Designation from FDA for R/R AML and soft tissue sarcoma, plus Orphan Drug Designation from EMA for R/R AML.