Moleculin Biotech Inc. (NASDAQ:MBRX) stock is trading lower on Tuesday after the company shared preliminary efficacy data from the first 45 patients enrolled in Part A of its pivotal Phase 2/3 MIRACLE trial that did not reach statistical significance.
However, the company noted that both Annamycin treatment arms showed higher remission rates than the control arm in patients with relapsed or refractory acute myeloid leukemia (R/R AML).
An independent monitoring committee recommended continuing the study without eliminating either experimental dose.
Annamycin Outperformed Control After One Treatment Cycle
The interim analysis, conducted on a full intent-to-treat basis without excluding any patients, showed complete remission (CR) rates of 43% for the 190 mg/m² Annamycin plus high-dose cytarabine (HiDAC) arm and 36% for the 230 mg/m² combination arm. The HiDAC control group recorded a CR rate of 12%.
Composite complete remission (CRc) reached 50% and 57% in the two Annamycin cohorts, compared with 29% for the control arm.
The company noted that all remission rates reflect outcomes after only a single treatment cycle, as required under the MIRACLE trial protocol.
Among the first 45 participants, 75.6% were older than 60 years, while 55.6% had previously received 7+3 chemotherapy and 31.1% had received venetoclax-based first-line treatment.
Independent Committee Recommends Trial Continue
The trial’s Independent Data Monitoring Committee concluded that although the primary endpoint had not reached statistical significance at this early stage, both Annamycin treatment arms demonstrated a strong numerical efficacy trend over the placebo plus HiDAC control arm.
The committee also determined that the efficacy results for the two Annamycin doses were too similar to justify removing either arm and recommended continuing the study as planned. Moleculin said it accepted the recommendation.
The company added that statistical significance was not expected at the first interim analysis because the trial uses a pre-specified O’Brien-Fleming group-sequential design, which reserves most of the statistical testing power for the final analysis.
MBRX Price Action: Moleculin Biotech shares were down 25.73% at $3.02 at the time of publication on Tuesday, according to Benzinga Pro data.
Mark Zaleski/ For the Tennessean / USA TODAY NETWORK
