Moleculin Announces Positive Interim Data in Annamycin Clinical Trials targeting Soft Tissue Sarcomas and Acute Myeloid Leukemia

HOUSTON — 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, today provided a preliminary update on recent clinical activity and expected near term milestones across its clinical development pipeline in its quarterly filing with the Securities and Exchange Commission.

“Despite a host of recent new drug approvals, the most important therapeutic tool for treating AML and advanced STS continues to be an anthracycline. We believe the data we are now showing in Annamycin’s clinical trials on those indications are demonstrating a potential to finally bring an anthracycline to the table for those patients who have until now been prevented from using them,” Walter Klemp, Chairman and Chief Executive Officer of Moleculin stated. “Importantly, as we continue to show zero cardiotoxicity in 100% of subjects in multiple studies, Annamycin is now also showing substantial activity in Phase 2 studies across two indications.”

“Having 38% of subjects with a median age of 68 in our MB-106 AML study receiving a full course of Annamycin show a complete response with durability of up to approximately 8 months and counting, we believe, is exceptional while also demonstrating no cardiotoxicity,” Dr. Paul Waymack, Senior Chief Medical Officer said. “Adding to this, we are showing in our Phase 1B/2 study with Annamycin treating soft tissue sarcoma (STS) with pulmonary metastases for subjects with no limit on prior therapies (median of 3; range of 1-11) PFS of 2.2 months or better for 59% of the subjects (N=32). In subjects with fewer prior therapies (prior therapies <2) and dosed with Annamycin at or below 330 mg/m2, this increased to 78% and, additionally, we are showing PFS of 3.4 months for 56% (N=9) of these subjects. Having a preliminary median of 11.3 months of overall survival once the subject has entered into our Phase 1B study (Extended OS), is exciting as these subjects were heavily pre-treated. For the overall study, we have an opportunity for the Extended OS and PFS data to get better as subjects continue to be monitored.”

Ongoing Clinical Trial Updates

Next Generation Anthracycline – Annamycin

Annamycin is the Company’s next-generation anthracycline that has been designed to be non-cardiotoxic (unlike currently prescribed anthracyclines) and has been shown in animal models to accumulate in the lungs at up to 30-fold the level of doxorubicin (a commonly prescribed anthracycline and the standard of care chemotherapy for advanced STS), as well as demonstrating the ability to avoid the multidrug resistance mechanisms that typically limit the efficacy of doxorubicin and other currently prescribed anthracyclines. An independent expert evaluated the first 62 subjects in the Company’s four clinical trials and confirmed that there are no signs of cardiotoxicity. In total 66 subjects (4 are yet to be reviewed) have been treated in the Company’s clinical trials and none have shown any signs of cardiotoxicity. This includes 50 subjects treated over the lifetime maximum anthracycline dose set by the U.S. Food and Drug Administration (FDA). Annamycin is currently in development for the treatment of both first line therapy and therapy for relapsed or refractory acute myeloid leukemia (AML), as well as, STS lung metastases (STS lung mets), and the Company believes the drug may have the potential to treat additional indications.

AML

The Company is currently conducting its Phase 1B/2 clinical trial evaluating 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) for the treatment of subjects with AML as both first line therapy and for subjects who are refractory to or relapsed after induction therapy (MB-106). clinicaltrialsregister.eu: EudraCT 2020-005493-10 or clinicaltrials.gov: NCT05319587. The Company has not treated any first line subjects to date.

Expected Upcoming Annamycin Milestones 

  • AML
    • In-depth data review and presentation of topline data on MB-106 clinical trial.
    • MB-106 End of Phase 2 (EOP2) Meeting.
    • Identify next phase of development / pivotal program.
    • Initiate pivotal program.
  • STS Lung Mets
    • Final MB-107 data readout.
    • Identify next phase of development / pivotal program.
    • Initiate first line study STS.

Flagship Immune/Transcription Modulator – WP1066

Moleculin is in ongoing discussions with multiple academic institutions in separate programs evaluating WP1066 for the treatment of glioblastomas and/or pediatric brain tumors. The Company expects to finalize agreements with Northwestern University and FDA filings in the early 2024 (Clinicaltrials.gov ID: NCT05879250).

Recent Activity Highlights

  • Ongoing progress in development of an intravenous formula for WP1066.
  • The Company supplied drug product to an externally funded pediatric brain tumor trial with WP1066 up to its conclusion in February 2023 and expects additional externally funded clinically trials for WP1066 (in combination with radiation) in 2023 in the U.S. and, possibly, in Southeast Asia.

Expected Upcoming Milestones

  • Report topline results from investigator-initiated Phase 1 study in pediatric brain tumors.
  • Seek external funding opportunities for an investigator-initiated clinical trial in adult and pediatric cancer patients in 2023.
  • Announce progress regarding an IV formulation by the end of 2023 or in early 2024.

Metabolism/Glycosylation Inhibitor WP1122 Portfolio

WP1122 was developed as a prodrug of 2 deoxy-D-Glucose (2-DG) to provide a more favorable pharmacological profile and was found to have greater potency than 2-DG monotherapy in preclinical models where tumor cells require higher glycolytic activity than normal cells. WP1122 has also been shown to have a greater antiviral effect than 2-DG against SARS-CoV-2 in MRC-5 cells in culture. The improved pharmacokinetic and pharmacodynamic (PK/PD) profile of WP1122 compared to 2-DG was noted in mice following oral dosing at equimolar (i.e., equivalent levels of 2-DG) doses. The WP1122 Portfolio includes numerous analogs, including WP1096, which has demonstrated the potential for broad antiviral capabilities in a wide range of in vitro models including multiple arenaviruses, filoviruses, Zika virus, and HIV. The Company looks forward to the potential of additional externally funded research to confirm such activity.

Expected Upcoming Milestones 

  • Report preliminary findings of National Institutes of Health (NIH) funded animal testing of WP1096 in the Tacaribe Arenavirus.
  • Identify investigators interested in initiating a clinical trial to study the safety, pharmacokinetics and efficacy of oral WP1122 in adult patients with GBM.

General Information on the Company’s Core Technologies

Annamycin currently has Fast Track Status (FTS) and Orphan Drug Designation (ODD) from the FDA for the treatment of soft tissue sarcoma, in addition to ODD for the treatment of acute myeloid leukemia. WP1066 has ODD for the treatment of GBM and has four indications designated for the FDA Rare Pediatric Disease Priority Review Voucher (PRV) Program. WP1122 has ODD and FTS for GBM, as well. For more information about the Company’s trials, please visit clinicaltrials.gov.

About Moleculin Biotech, Inc.

Moleculin Biotech, Inc. is a clinical stage pharmaceutical company with a growing pipeline, including Phase 2 clinical programs, for hard-to-treat tumors and viruses. The Company’s lead program, Annamycin is a next-generation anthracycline designed to avoid multidrug resistance mechanisms with little to no cardiotoxicity. Annamycin is currently in development for the treatment of relapsed or refractory acute myeloid leukemia (AML) and soft tissue sarcoma (STS) lung metastases.

Additionally, the Company is developing WP1066, an Immune/Transcription Modulator capable of inhibiting p-STAT3 and other oncogenic transcription factors while also stimulating a natural immune response, targeting brain tumors, pancreatic and other cancers, and WP1220, an analog to WP1066, for the topical treatment of cutaneous T-cell lymphoma. Moleculin is also engaged in the development of a portfolio of antimetabolites, including WP1122 for the potential treatment of COVID-19 and other viruses, as well as cancer indications including brain tumors, pancreatic and other cancers.

 

Contact

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