Moleculin Biotech, Inc. provided an update on recent activity and expected near term milestones across its clinical development pipeline. 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), 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 has reported no signs of cardiotoxicity in the first 42 subjects in the Company's three clinical trials, which total includes 32 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 STS lung metastases (STS lung mets) as well as both first line therapy and therapy for relapsed or refractory acute myeloid leukemia (AML), and the Company believes the drug may have the potential to treat additional indications. STS Lung Mets: The Company is currently in the Phase 2 portion of its ongoing U.S. Phase 1B/2 clinical trial evaluating Annamycin for the treatment of soft tissue sarcoma lung metastases (MB-107). Recent Activity Highlights: In the ongoing Phase 2 portion of the study, to date fifteen subjects have been enrolled and treated.

Thirteen subjects have been treated with at least two cycles of therapy at the confirmed Recommended Phase 2 Dose (RP2D) of 330 mg/m2 and are evaluable for efficacy. One subject was withdrawn from the study prior to receiving a scan due to the clinician's assessment. Per the protocol, follow-up imaging and RECIST evaluation is required for a subject to be included in the efficacy population.

One subject is pending initiation of the cycle 2 treatment. Including the three subjects treated at the same dose in the Phase 1B portion of this trial, this equates to fifteen total subjects measurable for efficacy at the 330 mg/m2 dose level. Including all measurable subjects at all dose levels in the Phase 1B portion of the trial, there have been thirty-one subjects treated with at least one cycle in this study and twenty-six have received two cycles of treatment.

For these subjects, the median time to entering the MB-107 trial from the time of initial diagnosis is estimated to be approximately 20 months, and these subjects have been mostly heavily treated previously for STS lung mets prior to entering the study. To date, 67% of the fifteen subjects receiving 330 mg/m2 and that have received end of cycle 2 scans in Phase 1B and Phase 2 have exhibited stable disease (SD) after receiving two cycles. The study has one subject who has not received end of cycle 2 scans and remains to be evaluated.

Of the thirty-one subjects in the Phase 1B and Phase 2 portions of the study, 73% (n=26) have exhibited SD after receiving two cycles. Some subjects are continuing with the study so, SD continues to be monitored, and overall survival is being followed for the study. These data are preliminary and subject to change.

An investigator sponsored Phase 1B/2 clinical trial was initiated in Poland in 2022 to study an alternative dosing regimen for Annamycin in the treatment of STS lung mets. This trial continues to enroll subjects and began dosing subjects in late 2022. 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 (MB106).

Recent Activity Highlights: Announced the publication of data from the successfully completed MB-105 European Phase 1 clinical trial assessing the safety and efficacy of Annamycin as a single agent for the treatment of adults with relapsed or refractory AML. The manuscript titled, "Results of a Phase 1 Study of Liposomal Annamycin for the Treatment of Relapsed or Refractory AML Patients After Induction Therapy," was published in the peer-reviewed British Journal of Cancer Research. The MB-106 clinical trial began dosing subjects in March 2023.

Six clinical sites in Poland and Italy have been activated for the MB-106 trial. The Company is planning for a total of up to eleven sites in the European Union (EU). In May 2023, the Company announced the completion of the first cohort in the Phase 1B portion of the MB-106 study.

In the first cohort, three subjects were treated, all of whom are relapsed from one or more prior therapies. Annamycin was dosed at 190 mg/m2, along with Cytarabine at 2.0 g/m2/day for five days (total dose of 10 g/m2), consistent with the familiar 7+3 regimen, combining daunorubicin and Cytarabine, typically used as a first-line induction therapy. In the Company's study therapy Annamycin replaces daunorubicin.

The Company, at the recommendation of the data safety committee, deemed the first cohort dose as safe and opened the second cohort with the Annamycin dose being increased to 230 mg/m2.