HOUSTON — September 28, 2026
Moleculin Biotech, Inc. announced publication of a peer-reviewed pooled analysis of the cardiac safety of Annamycin (L-Annamycin, naxtarubicin) in Frontiers in Cardiovascular Medicine. The analysis evaluated 90 patients across five clinical trials in acute myeloid leukemia (AML) and metastatic soft tissue sarcoma (STS), with paired echocardiographic data available for 78 patients. According to the published analysis, an independent cardio-oncology evaluation conducted through Cleveland Clinic found no clinical or subclinical evidence of treatment-related cardiotoxicity, including among patients receiving cumulative Annamycin exposures above traditional lifetime dose limits for conventional anthracyclines. The findings provide additional clinical safety data for Moleculin as it continues evaluating Annamycin in its oncology development programs, although the pooled analysis does not establish comparative safety versus conventional anthracyclines in a randomized trial.
Pooled Analysis Shows Stable Cardiac Function
The pooled analysis assessed multiple measures of cardiac function and found no significant treatment-associated decline in left ventricular ejection fraction (LVEF). Across the five trials, mean LVEF was 60.6% at baseline and 60.0% following treatment, with no statistically significant difference reported between the measurements (p=0.84). The analysis also found no association between cumulative Annamycin exposure and changes in LVEF and no relationship between patient age and LVEF changes. Additional assessments, including serial electrocardiograms, cardiac biomarkers such as troponin I/T, and global longitudinal strain measurements, reportedly showed no evidence of treatment-related cardiotoxicity. Patients received a median cumulative Annamycin dose of 660 mg/m², with the authors reporting cardiac findings despite cumulative exposure levels exceeding traditional lifetime limits used for conventional anthracyclines. The authors concluded that the findings support continued clinical evaluation of Annamycin as a potentially less cardiotoxic anthracycline approach.
Annamycin Designed to Address Anthracycline Cardiotoxicity
Anthracyclines remain widely used cancer therapies, but cumulative, dose-dependent cardiotoxicity can limit treatment intensity and future retreatment options. Moleculin developed Annamycin as a re-engineered anthracycline intended to retain antitumor activity while addressing limitations associated with conventional members of the class. Its liposomal formulation is designed to alter tissue distribution and reduce cardiac exposure. The newly published analysis builds on earlier clinical observations from the company’s development program, providing a broader assessment across patients treated in AML and metastatic STS studies. However, the analysis is a pooled evaluation of completed clinical trials rather than a randomized head-to-head comparison with another anthracycline, and the absence of detected cardiotoxicity in this dataset does not establish that Annamycin eliminates cardiac risk. Continued monitoring in larger and controlled studies will be important as clinical development progresses.
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Moleculin Advances Annamycin in MIRACLE AML Program
Annamycin is currently being evaluated in Moleculin’s MIRACLE development program for patients with relapsed or refractory AML. The company has initiated the MB-108 MIRACLE trial, described as a pivotal adaptive-design, multicenter, randomized, double-blind, placebo-controlled Phase 2/3 study evaluating Annamycin in combination with cytarabine, referred to as AnnAraC. The program follows the company’s earlier MB-106 Phase 1B/2 study and is intended to further evaluate the combination in relapsed or refractory AML. Moleculin is also developing Annamycin for soft tissue sarcoma lung metastases and is advancing additional investigational programs, including WP1066, an immune/transcription modulator targeting p-STAT3 and other oncogenic transcription factors, and WP1122, an antimetabolite being explored for pathogenic viral and selected cancer indications. The peer-reviewed cardiac analysis adds another clinical-development data set as Moleculin continues to evaluate Annamycin’s safety and therapeutic potential.
Source Moleculin Biotech press release
