Moleculin Announces Plans for MIRACLE Phase 3 Pivotal Trial

On August 1, 2024 Moleculin Biotech, Inc., (Nasdaq: MBRX) ("Moleculin" or the "Company"), a clinical stage pharmaceutical company with a broad portfolio of drug candidates targeting hard-to-treat tumors and viruses, reported the positive discussion in and outcome of its End of Phase 1B/2 (EOP1B/2) meeting with the US Food and Drug Administration (FDA) supporting the advancement of Annamycin in combination with Cytarabine (also known as "Ara-C" and for which the combination of Annamycin and Ara-C is referred to as "AnnAraC") to a Phase 3 pivotal trial for the treatment of AML patients who are refractory to or relapsed after induction therapy (R/R AML) (Press release, Moleculin, AUG 1, 2024, View Source [SID1234645265]). This Phase 3 "MIRACLE" trial (derived from Moleculin R/R AML AnnAraC Clinical Evaluation) will be a global trial, including sites in the US.

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"We thank the FDA’s Divisions of Hematologic Malignancies I and Cardiology and Nephrology, as well as related divisions, for a very constructive EOP1B/2 meeting and for their valuable feedback. Armed with this, we are now able to finalize plans for a pivotal approval pathway in AML," commented Walter Klemp, Chairman and Chief Executive Officer of Moleculin. "Importantly, consistent with the FDA’s recommendations, the adaptive Phase 3 trial will rely solely on CR (complete remission) at day 30 as the primary endpoint versus placebo, a standard we are confident Annamycin will meet and that provides an opportunity for accelerated approval."

Mr. Klemp continued: "We now also have additional confidence that our planned pivotal trial should be able to generate data supportive of a true value inflection point for shareholders in a timely manner. We plan to utilize a double-blind, placebo-controlled design, where the control arm is high dose cytarabine (HiDAC) plus placebo. There is considerable historical data on the use of HiDAC. You can see in this graphic that, compared to this historical data, AnnAraC has already demonstrated more than double the CR rate. The MIRACLE trial will initially focus on 2nd line treatment for R/R AML subjects and then follow-up with treatment for 3rd line R/R AML."

"This approach should also allow us to use this trial for approval in Europe. Based on our discussions with the FDA, we intend to amend our current investigational new drug application or IND to allow dosing above the lifetime maximum allowable dose (LTMAD) for currently prescribed anthracyclines in this trial in the US."

The Company obtained valuable input from the FDA and having resolved a number of key issues, believes that it has significantly de-risked the pathway to approval. The MIRACLE study, subject to appropriate future filings with and potential additional feedback from the FDA and their foreign equivalents, is expected to initially utilize an adaptive design whereby the first 75 patients will be randomized to receive HiDAC combined with either placebo, 190 mg/m2 of Annamycin, or 230 mg/m2 of Annamycin. At that point, the trial will be unblinded to select the Optimum Dose for Annamycin. For the second half of the trial, approximately 120 additional patients will be randomized to receive either HiDAC plus placebo or HiDAC plus the Optimum Dose of Annamycin. The selection of the Optimum Dose will be based not only on the absence of dose limiting toxicities but also on the overall balance of safety, pharmacokinetics and efficacy, consistent with the FDA’s new Project Optimus initiative.

Mr. Klemp concluded: "The FDA also wants to see the durability of response (DoR) and overall survival (OS) as secondary endpoints, as well as data for patients beyond 2nd line, which is why our plan includes a follow-on MIRACLE2 trial in 3rd line patients starting once the optimum dose is established in the MIRACLE trial. From a Company perspective, we believe this approach is the best of all worlds. We are not only making the leap into being a Phase 3 company, but our planned approval is also based on a primary endpoint comparing to a control that we are optimistic we can beat with the ability to report unblinded progress after just 75 patients. We are truly excited to launch the MIRACLE trial."

Moleculin Planned Significant Milestones

The Company has established plans for the following milestones:

2H 2024 – Begin contracting with MIRACLE trial sites
Q1 2025 – First subject treated in MIRACLE trial
Mid 2026 – Interim data (n=75) unblinded and Optimum Dose set for MIRACLE trial
2026 – Begin enrollment of 3rd line subjects in MIRACLE2
2027 – Enrollment ends in 2nd line subjects
2028 – Final Data for 2nd line subjects in MIRACLE
2H 2028 – Begin submission of a new drug application (NDA) the treatment of R/R AML for accelerated approval on primary endpoint of CR from MIRACLE
Annamycin currently has Fast Track Status and Orphan Drug Designation from the US Food and Drug Administration for the treatment of relapsed or refractory acute myeloid leukemia, in addition to Orphan Drug Designation for the treatment of soft tissue sarcoma. Furthermore, Annamycin has Orphan Drug Designation for the treatment of relapsed or refractory acute myeloid leukemia from the European Medicines Agency (EMA). For more information about the ongoing MB-106 Phase 1B/2 trial, visit clinicaltrialsregister.eu and reference EudraCT 2020-005493-10 or clinicaltrials.gov and reference NCT05319587.