Experimental chemo combo may improve control of hard-to-treat AML

Adding Moleculin Biotech’s experimental chemotherapy annamycin to the approved chemotherapy cytarabine may be more effective than cytarabine alone at controlling hard-to-treat acute myeloid leukemia (AML), interim data from a clinical trial show.

The Phase 2/3 MIRACLE trial (NCT06788756) is open to adults with AML, ages 18 to 80, whose cancer has not responded or has come back following one previous line of treatment. Enrollment is ongoing at sites in the U.S. and Europe.

Results so far have also shown no signs of heart toxicity with annamycin, further supporting its differentiated cardiac safety profile compared with conventional anthracyclines.

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“In addition to the positive interim MIRACLE results, we are just as excited by the feedback we are receiving from investigators about Annamycin and their enthusiasm for participating in the study,” Walter Klemp, Moleculin’s CEO, said in a company press release announcing its latest financial results and business updates. “Their response reflects … growing recognition of Annamycin’s potential, with its encouraging data generated to date and differentiated [heart] safety profile, to play an important role in the treatment landscape.”

In MIRACLE’s first part, which is ongoing, participants are randomly assigned to receive either one of two doses of annamycin plus cytarabine or cytarabine plus a placebo. The main goal is to determine the optimal annamycin dose for further testing in the trial’s second part, which will include a larger number of patients.

The first part of the trial aims to enroll a total of 90 participants. According to Moleculin, enrollment is expected to wrap up next month, with results anticipated between December and early 2027. The second part is expected to start in the first half of 2027, with recruitment expected to run through 2028.

“As we advance toward the 90-patient milestone and next unblinded efficacy readout, this strong investigator engagement adds to our confidence in the program and the potential for Annamycin to meaningfully improve outcomes for patients,” Klemp said.

If MIRACLE results are positive, the company expects to complete submission of a regulatory application in 2029 seeking annamycin’s approval in the U.S. for relapsed or refractory AML.

Moleculin is also planning to start clinical trials next year to test annamycin in children with AML and as a third-line treatment for adults with relapsed or refractory AML.

Annamycin designed to limit heart damage from chemotherapy

AML is an aggressive form of blood cancer. Chemotherapies, which are drugs that kill rapidly growing cancer cells, are a mainstay of AML treatment. But some chemotherapies, including anthracyclines — the class that includes annamycin — can cause heart damage as a side effect.

Annamycin is a novel anthracycline designed to retain cancer-killing effects while minimizing heart damage.

Early blinded results from the first 30 participants in MIRACLE’s first part showed higher response rates than those historically reported with cytarabine alone. Because the results were blinded, researchers did not know which participants had received annamycin plus cytarabine and which had received cytarabine plus placebo. Still, the findings suggested that adding annamycin could be having a beneficial effect compared with cytarabine alone.

The trial was designed to allow an interim look at results after 45 participants had been treated and evaluated. Those findings, announced last month, focused on the percentage of participants who achieved complete remission — no detectable cancer and recovery of blood counts — and composite complete remission, which also included patients with no detectable cancer but incomplete recovery of certain blood counts.

Complete remission rates were at least three times higher with the low-dose annamycin combo (43%) and the high-dose combo (36%), compared with cytarabine plus placebo (12%). Rates of composite complete remission were also higher in the annamycin groups (50% with the low dose and 57% with the high dose) relative to the cytarabine plus placebo group (29%).

Annamycin continued to show the “encouraging safety profile previously observed in clinical studies,” the release stated, with “no evidence of [heart toxicity].”