Moleculin Gains ASCO Platform for Annamycin Cardiac Safety Data Across 90 Patients in Five Trials

Pooled cardiac safety data for Moleculin Biotech's Annamycin (naxtarubicin) will reach one of oncology's most scrutinised peer forums on May 30, with implications that extend well beyond the clinical team into CMC planning and regulatory submission strategy for next-generation anthracyclines.

The accepted abstract, titled "Cardiac safety of L-annamycin at high cumulative anthracycline exposure: Pooled analysis," draws on independent cardiac safety reviews across five completed trials in patients with acute myeloid leukemia (AML) and soft tissue sarcoma. Of 90 patients treated, 78 had source-verified pre- and post-treatment left ventricular ejection fraction (LVEF) assessments. Median cumulative dose reached 660 mg/m², a figure that substantially exceeds conventional lifetime anthracycline limits, yet mean LVEF change from baseline was -0.12% (95% CI, -1.34 to 1.09; p = 0.84), with no statistically significant finding.

No correlation emerged between cumulative dose and LVEF change (p = 0.12), nor between patient age and LVEF change (p = 0.73). Independent review of serial ECGs, cardiac biomarkers, and global longitudinal strain measurements found no evidence of drug-induced cardiotoxicity across the dataset.

For regulatory affairs leads, the dataset's construction carries weight: pooled analyses spanning sponsor- and investigator-initiated trials, with source-verified cardiac endpoints, represent the kind of structured safety evidence that can anchor a differentiated labeling narrative under 21 CFR Part 312 and ICH E14 cardiac safety guidance. The absence of a cumulative dose-toxicity relationship, if sustained through the ongoing pivotal Phase 2b/3 MIRACLE trial in AML, would directly challenge the dose-ceiling assumptions embedded in current anthracycline prescribing and could reshape the benefit-risk framework presented in a future NDA.

From a clinical manufacturing standpoint, removing a cardiotoxicity-driven dose ceiling changes the scale-up calculus. Higher cumulative dosing regimens, if confirmed safe, alter batch sizing assumptions, cycle frequency planning, and the sterility assurance requirements tied to multi-cycle administration under 21 CFR Part 211.

Previously reported Phase 1b/2 data in second-line AML showed a 50% complete remission rate, a 60% composite complete remission rate, and median overall survival of 12.39 months in the intent-to-treat population, results that provide the efficacy context against which the cardiac safety profile will be evaluated at ASCO.

The poster session runs May 30, 2026, 1:30–4:30 PM CDT at Poster Board #8, with the MIRACLE trial's eventual readout serving as the next measurable checkpoint for the cardiac safety narrative now being established in the pooled dataset.

Source: Moleculin Biotech, Inc. via GlobeNewswire, May 21, 2026.