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Median Overall Survival (OS) of 15 months for subjects with complete remission (n=8) Median OS of 2nd Line efficacy evaluable population of 12 months (n=9) Median OS of Intent to Treat population (1L-7L) of 9 months (n=22) OS demonstrated by Annamycin in the MB-106 trial is significantly above industry expectations for relapsed AML (4-6 months) Clinical study report anticipated in Q1 2026 Company continues to execute Part A of the pivotal MIRACLE Phase 3 trial HOUSTON, Aug. 27, 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 the completion of its Phase 1B/2 (MB-106) clinical trial evaluating 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 subjects with acute myeloid leukemia (AML). Database lock for the trial is expected by the end of September, with the final clinical study report (CSR) projected to be published in early Q1 2026. In total, 22 subjects were enrolled in the trial, with all subjects (1L-7L) who received AnnAraC per protocol having completed their efficacy evaluations (n=20). The updated overall survival (OS) data reveal the following: Median OS for Complete Remissions (CR): 15 months (n=8) with 4 subjects alive at study close Median OS for the intent to treat (ITT) Population (1L-7L): 9 months (n=22; 13 subjects experienced an event, 9 subjects censored) Median OS for 2L Efficacy Evaluable Population: 12 months (n=9) “Industry publications1 note that the typical OS for relapsed AML patients is roughly 4-6 months, these results highlight a remarkable improvement, exceeding expectations by 30% or more,” said Walter Klemp, Chairman and CEO of Moleculin Biotech. As previously reported, 8 subjects in the ITT population of 22 (36%) achieved a complete remission (CR) following treatment with AnnAraC. Among the subjects treated in the second line (2L) setting (n=10), the CR rate (the same primary efficacy endpoint as in the ongoing Phase 2B/3 pivotal MIRACLE trial), was 50%. Median durability for the 8 subjects achieving a CR was 10 months and continuing at the end of the study. CR durability ranged from 2 months to 22 months. CRs were achieved in subjects with a variety of prior treatments, including traditional 7+3 and venetoclax regimens. “We are glad to finally be in a position to close out our last Phase 2 AML trial, MB-106 by having completed follow-up on all subjects – some with durable CRs continuing – with database lock expected by the end of next month. While still technically preliminary, we are extremely pleased with the results of the MB-106 trial and look forward to the final CSR. These 2L data formed the basis for the design of the Phase 2B/3 pivotal MIRACLE trial with which we aim to gain eventual approval of Annamycin to serve the unmet need in 2L AML,” added Walter Klemp, Chairman and CEO of Moleculin. “We continue to see meaningful, positive trends across all data points, particularly in overall survival and durability. Of note, an 80+ yr old subject who achieved a CR with one cycle of Annamycin and then received two maintenance cycles of Annamycin finally relapsed after 600+ days. He then received a fourth round of Annamycin under compassionate use and is now back in remission. These data are very exciting and continue to give us hope that Annamycin has the potential to address the significant unmet need for safe and effective therapies for R/R AML. We also need to reemphasize that we have not seen any cardiotoxicity in any of the subjects to date, a key aspect of Annamycin.” “We can now also report that 50% of subjects achieving CR moved on to a curative bone marrow transplant, which is the most sought-after goal of any induction therapy in AML,” Mr. Klemp continued. “The results we have seen in 2L patients are better than any drug ever approved for second line AML and more than double the average for the last five drugs approved for 2L use.” “Looking ahead, we are focused on driving Part A of our Phase 3 MIRACLE trial forward and remain on track recruit the first 45 enrolled patients before the end of this year on which safety and efficacy will be unblinded. The final data from MB-106, coupled with the expected data from the MIRACLE trial will be invaluable as we continue to unlock the full potential of Annamycin for the treatment of AML,” concluded Mr. Klemp. The median age of subjects in MB-106 is 68 years. A total of 18 subjects had relapsed/refractory AML and 4 subjects were first line treatment. Two subjects discontinued early due to allergic reactions. All subjects who completed treatment had undergone post therapy disease response assessments (bone marrow assessment and/or peripheral blood evaluation) (Day 15 or later). No clinically significant signs of cardiotoxicity were noted during or after treatment in any of the subjects enrolled. The combination was well tolerated with myelosuppression and infections being the main adverse events (AEs). All data from MB-106 is preliminary and subject to change. Annamycin, also known by its non-proprietary name of naxtarubicin, currently has Fast Track Status and Orphan Drug Designation from the FDA for the treatment of relapsed or refractory acute myeloid leukemia, in addition to Orphan Drug Designation for the treatment of soft tissue sarcoma. Furthermore, Annamycin has Orphan Drug Designation for the treatment of relapsed or refractory acute myeloid leukemia from the EMA. The Company is currently evaluating 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”) in a Phase 3 pivotal trial for the treatment of AML patients who are refractory to or relapsed after induction therapy (R/R AML). This global Phase 3 “MIRACLE” trial (derived from Moleculin R/R AML AnnAraC Clinical Evaluation) includes sites in the US, Europe and the Middle East. For more information about the MIRACLE trial, visit clinicaltrials.gov and reference identifier NCT06788756. Additionally, the clinical trial in the EU is on euclinicaltrials.eu and the reference identifier there is 2024-518359-47-00. 1 – Bruno C. Medeiros, Is there a standard of care for relapsed AML?, Best Practice & Research Clinical, Haematology, Volume 31, Issue 4, 2018, Pages 384-386, ISSN 1521-6926; Roboz GJ, Sanz G, et al. Guadecitabine vs TC in relapsed/refractory AML after intensive chemotherapy: a randomized phase 3 ASTRAL-2 trial. Blood Adv. 2024 Apr 23;8(8):2020-2029. doi: 10.1182/bloodadvances.2023012062. PMID: 38231126; PMCID: PMC11103175.; Faderl S, Wetzler M, et al. Clofarabine plus cytarabine compared with cytarabine alone in older patients with relapsed or refractory acute myelogenous leukemia: results from the CLASSIC I Trial. J Clin Oncol. 2012 Jul 10;30(20):2492-9. doi: 10.1200/JCO.2011.37.9743. Epub 2012 May 14. PMID: 22585697; PMCID: PMC4874149. 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 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, 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 is also engaged in the development of 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 MB-106 database lock for the trial and the publication of the final CSR, the timing of the release of the initial data on the first 45 subjects in the MIRACLE trial, and the Company’s ability to reconcile the US and EU MIRACLE protocols with the FDA and EMA, respectively. 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, LLCJenene Thomas(908) 824-0775MBRX@jtcir.com

- On track to start dosing in pivotal, adaptive Phase 3 clinical trial (the "MIRACLE" trial) designed for possible accelerated approval of Annamycin in combination with cytarabine for the treatment of R/R AML in Q1 2025 - Median durability of CRc in MB-106 Annamycin+ Cytarabine AML clinical trial continues to climb - now past 8 months - Recent virtual AML KOL event underscores how Annamycin could significantly change the AML treatment landscape; Replay available here - Company to host conference call and webcast today, Monday, November 11th at 8:30 AM ET HOUSTON, Nov. 11, 2024 /PRNewswire/ -- 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 tumors and viruses, today reported its financial results for the quarter ended September 30, 2024. As previously announced, the Company will host a conference call and live audio webcast to discuss the operational and financial results at 8:30 AM ET on Monday, November 11, 2024 (details below). "We are thrilled to have emerged as a late stage company. Our focus remains on the ramp up for and execution of our upcoming MIRACLE trial. We have been extremely active and our recent interactions with potential clinical trial sites globally have been overwhelmingly positive as we prepare for the start of enrollment and dosing early next year. We believe with our recent clinical and regulatory 'wins,' we have foundationally set the stage for a transformational year ahead and the opportunity to drive significant value for all stakeholders. With that said, we continue to follow our CRc (complete response composite) preliminary data from our MB-106 Phase 1B/2 AML clinical trial. We are also pleased with the median durability continuing to climb – and is now in excess of 8 months," commented Walter Klemp, Chairman and Chief Executive Officer of Moleculin. Recent Highlights Appointed Daniel D. Von Hoff, M.D., F.A.C.P., FASCO, FAACR, leading expert in Pancreatic Cancer to its Scientific Advisory Board to Support Development of Annamycin; Hosted a Virtual Acute Myeloid Leukemia KOL event with internationally renowned Acute Myeloid Leukemia (AML) Key Opinion Leaders to discuss Annamycin, the use of anthracyclines, how Annamycin could significantly change the AML treatment landscape, and the Company's recently announced global Phase 3 pivotal trial for the treatment of AML patients who are refractory to or relapsed after induction therapy (R/R AML) (the "MIRACLE" trial); Presented positive in vivo efficacy data of Annamycin in orthotopic and experimental lung metastatic models of Sarcoma in a poster titled "Annamycin: Opening New Doors for Organotropic Targeting of Primary and Metastatic Lung Cancer," at the IASLC 2024 World Conference on Lung Cancer; Commenced enrollment and treatment of patients in the Investigator-initiated Phase 2 study evaluating WP1066 in combination with radiation therapy for the treatment of adults with glioblastoma; and Closed a $5.5 million financing upfront with up to an additional $11.0 million of potential aggregate gross proceeds upon the exercise in full of milestone-linked warrants. Clinical Development Update Annamycin is currently being evaluated in ongoing clinical trials for the treatment of relapsed or refractory acute myeloid leukemia (AML) and soft tissue sarcoma (STS) lung metastases. Annamycin currently has Fast Track Status and Orphan Drug Designation from the FDA for the treatment of relapsed or refractory acute myeloid leukemia, in addition to Orphan Drug Designation for the treatment of soft tissue sarcoma. Furthermore, Annamycin has Orphan Drug Designation for the treatment of relapsed or refractory acute myeloid leukemia from the European Medicines Agency (EMA). AML The Company recently announced the positive discussion and outcome of its End of Phase 1B/2 (EOP1B/2) meeting with the US Food and Drug Administration (FDA) supporting the advancement 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") to a Phase 3 pivotal trial for the treatment of AML patients who are refractory to or relapsed after induction therapy (R/R AML). This Phase 3 "MIRACLE" trial (derived from Molecul in R/R AML AnnAraC Clinical Evaluation) will be a global trial, including sites in the US. The MIRACLE study, subject to appropriate future filings with and potential additional feedback from the FDA and their foreign equivalents, is expected to initially utilize an adaptive design whereby approximately the first 75 to 90 subjects will be randomized to receive high dose cytarabine (HiDAC) combined with either placebo, 190 mg/m2 of Annamycin, or 230 mg/m2 of Annamycin. At that point, the trial will be unblinded to select the optimum dose for Annamycin. For the second part of the trial, approximately 240 additional subjects will be randomized to receive either HiDAC plus placebo or HiDAC plus the optimum dose of Annamycin. The selection of the optimum dose will be based not only on the overall balance of safety, tolerability, pharmacokinetics and efficacy, consistent with the FDA's new Project Optimus initiative. Expected Milestones for Annamycin AML Development Program 4Q 2024 – Contracting with MIRACLE trial sites and IRB approval 1Q 2025 – First subject treated in MIRACLE trial 4Q 2025 – Recruitment and overall efficacy rate update (n=45) 2H 2026 – Interim efficacy and safety data (n=90) unblinded and Optimum Dose set for MIRACLE trial 2027 – Begin enrollment of 3rd line subjects in MIRACLE2 2027 – Enrollment ends in 2nd line subjects 2028 – Primary efficacy data for 2nd line subjects in MIRACLE 2028 2H – Begin submission of a Rolling New Drug Application (NDA) for the treatment of R/R AML for accelerated approval on primary endpoint of CR from MIRACLE STS Lung Metastases As previously announced, the Company completed enrollment in the Phase 2 portion of its U.S. Phase 1B/2 clinical trial evaluating Annamycin as monotherapy for the treatment of soft tissue sarcoma lung metastases. Subjects who had stable disease at the time of study discontinuation were followed for progression free response and overall survival. The study database is locked, and the clinical study report is being written and should be completed in early 2025 and will be released in detail at that time Expected Milestones for Annamycin STS Lung Mets Development Program 2025 – Final MB-107 data readout 2025 – Identify next phase of development / pivotal program Summary of Financial Results for the Third Quarter 2024 Research and development (R&D) expense was $4.9 million and $3.3 million for the three months ended September 30, 2024 and 2023, respectively. The increase over the prior year period is mainly related to costs incurred for clinical trials (clinical research organization and drug production) and sponsored research costs. General and administrative expense was $2.2 million and $2.6 million for the three months ended September 30, 2024 and 2023, respectively. The decrease of $0.4 million is mainly related to a decrease in regulatory and legal fees. As of September 30, 2024, the Company had cash and cash equivalents of $9.4 million and believes that the existing cash and cash equivalents as of September 30, 2024, will be sufficient to fund planned operations into the first quarter of 2025. Conference Call and Webcast Moleculin management will host its quarterly conference call and webcast for investors, analysts, and other interested parties on Monday, November 11, 2024 at 8:30 AM ET. Interested participants and investors may access the conference call by dialing (877) 407-0832 (domestic) or (201) 689-8433 (international) and referencing the Moleculin Biotech Conference Call. The live audio webcast will be accessible on the Events page of the Investors section of the Moleculin website, moleculin.com, and will be archived for 90 days. 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 anthracycline designed to avoid multidrug resistance mechanisms and to eliminate 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 is initiating the MIRACLE ( Molecul in 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, 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 is 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 is also engaged in the development of 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 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 Company's forecasted cash burn rate (including its estimate of cash sufficient to meet its projected operating requirements) and the achievement of the expected milestones set forth above. 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 [email protected] SOURCE Moleculin Biotech, Inc. WANT YOUR COMPANY'S NEWS FEATURED ON PRNEWSWIRE.COM? 440k+ Newsrooms & Influencers 9k+ Digital Media Outlets 270k+ Journalists Opted In GET STARTED