Second-line annamycin plus cytarabine injections demonstrated promising responses in patients with relapsed or refractory acute myeloid leukemia.
Annamycin (naxtarubicin) in combination with cytarabine demonstrated favorable response rates in the second-line setting for patients with relapsed or refractory acute myeloid leukemia (AML), according to blinded efficacy data from the phase 2b/3 MIRACLE trial (NCT06788756).1
Notably, data from the study, which is evaluating annamycin plus cytarabine vs placebo plus cytarabine, are expected to be unblinded ahead of June 30, 2026.1,2
Blinded data from the trial showed that evaluable patients (n = 45) achieved a composite complete remission (CRc) rate higher than 40% and a complete remission (CR) rate of approximately 30%.1 These outcomes compared favorably with CR rates of approximately 17% to 18% from previous clinical trials evaluating cytarabine alone in similar patient populations.
Annamycin currently holds fast track and orphan drug designations from the FDA for relapsed/refractory AML. Additionally, annamycin received a fast track designation from the
“The data coming from MIRACLE [are] encouraging. For decades, cytarabine monotherapy regimens, although one of the current standards of care [SOC], have set a relatively low bar in relapsed/refractory AML, with historical CR rates hovering around 17% to 18% in previously referenced clinical trials,” Walter Klemp, chairman and chief executive officer of Moleculin Biotech, stated in a news release. “With our trial comparing 2 arms of annamycin in combination with cytarabine compared [with] cytarabine with a placebo, we are looking forward to the opportunity of showing annamycin is additive to cytarabine alone in a head-to-head trial. Against this backdrop, the data emerging from MIRACLE highlight what could be a substantial advancement, suggesting that we may finally be moving beyond the limitations that have defined SOC outcomes.”
The multicenter, randomized trial is enrolling patients 18 to 80 years of age with pathologically confirmed AML who have received a 1 prior line of therapy.2 Patients also need to have an ECOG performance status of 2 or less and a life expectancy longer than 6 weeks at the time of screening.
If patients receive investigational therapy within the 4 weeks of their first dose or prior mediastinal radiotherapy, have central nervous system involvement, have impaired cardiac function, or have a prior or current diagnosis of acute promyelocytic leukemia or myelodysplastic syndrome, they are not included in the trial.
In part A of the study, patients are being randomly assigned to 1 of 3 arms to receive annamycin at 190 mg/m² per day plus cytarabine; annamycin at 230 mg/m² per day plus cytarabine; or cytarabine plus placebo. Part B will include 2 arms, where patients will be randomly assigned to received annamycin at the optimal dose determined in part A plus cytarabine; or placebo plus cytarabine.
The primary end point of part A is to determine the optimal dose of annamycin for part B. Part B’s primary end point is CR rate following 1 cycle of treatment.
As of May 1, 2026, 56 patients had been recruited for the trial, with the ultimate goal of recruiting 90 total patients for part A of the study.1 The median age among the first enrolled patients is in the mid-60s, with more than 30% of patients having relapsed/refractory disease following a venetoclax (Venclexta)-based prior line of therapy. The 90th patient is expected to be enrolled in the third quarter of 2026.
Importantly, the reported CR and CRc rates reflect the pooled study population rather than a head-to-head comparison of annamycin plus cytarabine and cytarabine plus placebo.
The next milestone will be the unblinding of efficacy data from the first 45 patients enrolled in part A. Following completion of part A, the trial is designed to transition to part B.
