The poster presentation, titled "Cardiac safety of L-annamycin at high cumulative anthracycline exposure: Pooled analysis," highlighted findings from a pooled analysis across five completed clinical trials evaluating

The poster presentation, titled "Cardiac safety of L-annamycin at high cumulative anthracycline exposure: Pooled analysis," highlighted findings from a pooled analysis across five completed clinical trials evaluating Annamycin in patients with acute myeloid leukemia (AML) and soft tissue sarcoma. The analysis demonstrated no detectable cardiotoxicity despite cumulative exposure levels that substantially exceeded traditional lifetime anthracycline dose limitations.

"This poster presentation adds significant momentum to the growing clinical evidence supporting Annamycin's differentiated profile," said Walter Klemp, Chairman and CEO of Moleculin Biotech. "Anthracyclines remain among the most effective agents in oncology, yet their long-term use has historically been constrained by irreversible cumulative cardiotoxicity. These data continue to suggest that Annamycin may have the potential to fundamentally change that paradigm."

The pooled analysis included 90 patients treated with Annamycin across five completed clinical trials, with source-verified paired pre- and post-treatment left ventricular ejection fraction (LVEF) assessments available for 78 patients. Patients received a median cumulative Annamycin dose of 660 mg/m², with exposure ranging from 210 mg/m² to 2,970 mg/m² — levels that, in many cases, substantially exceeded conventional anthracycline lifetime dose thresholds.

Key findings from the analysis included:

  • No statistically significant difference in LVEF from baseline to final assessment (mean difference: -0.12%; 95% CI, -1.34 to 1.09; p = 0.84)
  • No correlation between cumulative Annamycin dose and change in LVEF (p= 0.12)
  • No correlation between patient age and change in LVEF (p=0.73)
  • Independent review of serial ECGs, cardiac biomarkers, cardiac adverse events and available global longitudinal strain measurements demonstrated no evidence of drug-induced cardiotoxicity
  • Independent cardiac review conducted through the Cleveland Clinic Division of Cardiovascular Medicine



     

Importantly, the data were independently reviewed by Cleveland Clinic cardiology specialists, providing additional external validation to the cardiac safety findings.

"The absence of detectable cardiotoxicity at exposure levels well beyond conventional anthracycline limits is particularly encouraging," added Mr. Klemp. "If confirmed in larger studies, we believe Annamycin could potentially enable patients to continue benefiting from anthracycline-based therapy without the traditional cumulative cardiac burden associated with currently prescribed agents."

The poster also highlighted previously reported efficacy findings from Moleculin's Phase 1b/2 AML study evaluating Annamycin in combination with cytarabine, which demonstrated:

  • 50% complete remission (CR) rate
  • 60% composite complete remission (CRc) rate
  • Median overall survival of 12.39 months in the intent-to-treat population
  • 50% of responders were able to receive a potentially curative bone marrow transplant



     

Moleculin believes the growing body of cardiac safety data further strengthens the rationale for its ongoing pivotal Phase 2b/3 MIRACLE trial evaluating AnnAraC® (Annamycin plus cytarabine) in relapsed or refractory AML.

Anthracyclines remain one of the most widely used and effective classes of chemotherapy agents across multiple cancer types; however, their use has historically been limited by cumulative dose-dependent cardiotoxicity. Annamycin was specifically designed to avoid multidrug resistance mechanisms while potentially eliminating the cardiotoxicity commonly associated with currently prescribed anthracyclines.

The Company's ongoing pivotal Phase 2b/3 MIRACLE trial continues to evaluate Annamycin in relapsed or refractory AML. Unblinding from the first 45 patients from this study is on track for June 2026.