Moleculin Biotech, Inc. announced encouraging updated preliminary blinded results from Part A of its pivotal Phase 2/3 MIRACLE trial (MB-108) evaluating Annamycin in combination with cytarabine (AnnAraC) for the treatment of relapsed or refractory acute myeloid leukaemia (R/R AML). The latest data reinforce the therapy’s potential efficacy while continuing to demonstrate a favourable cardiac safety profile.
Preliminary Results Show Strong Remission Rates
The latest blinded analysis includes 62 evaluable patients enrolled in the study. According to the company:
Complete Remission (CR): 24%
Composite Complete Remission (CRc): 37%
Notably, 30 of the 62 patients (48%) had previously received venetoclax-based therapy, which has become a standard first-line treatment for older or medically unfit AML patients.
Among these difficult-to-treat patients:
CR: 23%
CRc: 37%
These remission rates were almost identical to those observed in the overall study population, suggesting that previous venetoclax treatment did not adversely affect patient responses.
Company Highlights Encouraging Clinical Trend
Walter Klemp, Chairman and Chief Executive Officer of Moleculin Biotech, said nearly half of the evaluable patients entered the study after failing venetoclax therapy, a patient group historically associated with poor outcomes. He noted that published studies report salvage remission rates of only about 13%, with median survival of approximately 2.4 months in this setting. Therefore, maintaining a blinded CRc rate of around 37% despite the increasing proportion of heavily pre-treated patients strengthens confidence in the programme. Klemp also explained that because the current analysis remains blinded and includes patients from the control arm, the remission rates are naturally lower than the unblinded Annamycin-arm data reported earlier.
Cardiac Safety Continues to Differentiate Annamycin
Equally significant, the company reported no evidence of cardiotoxicity, based on cardiac ejection fraction measurements and adverse event monitoring. This finding remains one of Annamycin’s key differentiators from conventional anthracycline chemotherapy drugs, which are often associated with heart damage. According to the company, the combination of promising efficacy, continued cardiac safety and rapid patient recruitment positions the MIRACLE programme for a critical development phase.
Blinded Results Remain Consistent
Although the current analysis includes patients receiving placebo and therefore cannot be directly compared with earlier unblinded data, remission outcomes have remained remarkably stable. Across three blinded analyses involving 30, 45 and 62 evaluable patients, the CRc rate has consistently remained between approximately 37% and 40%. During the same period, the proportion of patients entering the trial after failure of first-line venetoclax therapy increased significantly—from 31.1% to 48%—making the study population progressively more challenging.
Earlier Interim Analysis Demonstrated Higher Response Rates
In June 2026, Moleculin released unblinded interim data from the first 45 patients, which showed a clear efficacy advantage for both Annamycin treatment arms over the control group.
The results included:
| Treatment Arm | CR | CRc |
| Annamycin 190 mg/m² + HiDAC | 43% | 50% |
| Annamycin 230 mg/m² + HiDAC | 36% | 57% |
| HiDAC Control | 12% | 29% |
Importantly, these remission rates were achieved after only one treatment cycle, unlike several historical AML studies that permitted multiple treatment cycles. Consequently, Moleculin believes that comparing the final Annamycin arm with its concurrent randomized control arm will provide the most meaningful assessment for regulatory review.
About the MIRACLE Trial
The MIRACLE (Moleculin R/R AML AnnAraC Clinical Evaluation) study is a global, randomized, double-blind, placebo-controlled, adaptive Phase 2/3 clinical trial evaluating Annamycin plus cytarabine in adults with relapsed or refractory AML following one prior induction therapy.
Part A evaluates two Annamycin doses:
190 mg/m² + cytarabine
230 mg/m² + cytarabine
These are compared with:
Cytarabine plus placebo
The trial is being conducted across seven countries, with 33 active clinical sites in the United States, the European Union and other European nations. Moleculin plans to expand to at least 45 sites during Part B.
Regulatory Advantages Strengthen Development Programme
Annamycin continues to benefit from several important regulatory incentives.
The drug has received:
FDA Fast Track Designation for relapsed or refractory AML
FDA Orphan Drug Designation for AML
FDA Orphan Drug Designation for soft tissue sarcoma
European Medicines Agency (EMA) Orphan Drug Designation for relapsed or refractory AML. In addition, Annamycin is protected by composition-of-matter patents through 2040, with the potential for patent exclusivity extending to 2045.
Looking Ahead
With enrollment approaching completion, Moleculin believes the programme is entering an important value-creating phase.
The company expects the upcoming comprehensive unblinded results to:
Validate Annamycin’s differentiated efficacy and safety profile.
Support advancement into Phase 3 (Part B).
Strengthen regulatory submissions.
Enhance strategic partnership opportunities.
Potentially establish Annamycin as a new treatment option for patients with relapsed or refractory AML. As reported by pharmabiz.com, if the final data confirm the current trends, the MIRACLE trial could represent a significant milestone in the development of a next-generation anthracycline that combines encouraging anti-leukaemia activity with the absence of cardiotoxicity—a longstanding challenge in AML treatment.