On March 23, 2026 Moleculin Biotech, Inc., (Nasdaq: MBRX) ("Moleculin" or the "Company"), reported 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.

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"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 45th 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.

(Press release, Moleculin, MAR 23, 2026, View Source [SID1234663824])