On December 17, 2025 Moleculin Biotech, Inc., (Nasdaq: MBRX) ("Moleculin" or the "Company"), reported positive results from the Emory University physician-sponsored Phase 1 clinical trial conducted at the Aflac Cancer and Blood Disorders Center at Children’s Healthcare of Atlanta led by pediatric oncologist, Tobey MacDonald, MD, who discovered STAT3 is critical to certain childhood brain tumors and currently serves as Professor of Pediatrics and Director of the Pediatric Neuro-Oncology Program.
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WP1066 is Moleculin’s flagship Immune/Transcription Modulator designed to stimulate the immune response to tumors by inhibiting the errant activity of regulatory T cells while also inhibiting key oncogenic transcription factors, including p-STAT3 (phosphorylated signal transducer and activator of transcription 3), c-Myc (oncogene driving many aggressive cancers) and HIF-1α (hypoxia-inducible factor 1α). These transcription factors are widely sought targets because of their role in cancer cell survival and proliferation, angiogenesis (coopting vasculature for blood supply), invasion, metastasis, and inflammation associated with tumors.
"The results of this first-in-child trial show some encouraging signals of activity in a highly aggressive chemotherapy resistant brain cancer, such as partial tumor response in a diffuse intrinsic pontine glioma (DIPG) patient and clear anti-tumor immune changes," said Dr. MacDonald.
For the Phase 1 trial, 10 children were treated with WP1066 twice daily for 14 days to determine the maximum feasible dose. Compassionate use treatment in three children with high-grade glioma was also evaluated. Results showed there was no significant toxicity, and a maximum feasible dose was determined. Importantly, WP1066 suppressed the expression of STAT3, inhibiting its activity and demonstrating anti-tumor immune responses.
While the preclinical efficacy of WP1066 had been previously demonstrated, and its effectiveness had been studied among adults, this trial was the first to test it in children. Dr. MacDonald and his team recruited pediatric patients with high-grade glioma, which include diffuse midline glioma (DMG) and DIPG, and account for most pediatric brain tumor-related deaths. Both DMG and DIPG have an average survival rate of nine to 11 months following diagnosis. Additionally, patients with relapsed medulloblastoma and ependymoma who have no accepted standard therapy following a relapse were also included in the study. Thus, Dr. MacDonald’s research helps fill a critical need to identify new treatment options for patients with these incurable tumors.
Mr. Walter Klemp, Chairman and CEO of Moleculin, "We are very encouraged by the positive results from our Phase 1 clinical trial evaluating WP1066 in children with recurrent malignant brain tumors. These early data show that WP1066 has the ability to activate meaningful anti-tumor immune responses, an important proof of mechanism in a patient population with extremely limited treatment options. While still early, these findings reinforce the potential of WP1066 as a novel immunomodulatory approach for some of the most difficult-to-treat pediatric brain cancers. We are deeply grateful to Dr. MacDonald and his team, and the patients and families who participated in this study. We look forward to the continued advancement of WP1066 as a potential therapy that can make a real difference for children facing these devastating diseases."
Results from the study were recently published in the Journal of Clinical Investigation Insight. For more information about the WP1066 Phase 1 clinical trial, visit clinicaltrials.gov and reference identifier NCT04334863.
The results of this study are the foundation of the Phase 2 concept Dr. MacDonald’s team would like to pursue in a follow-up trial. The current study was funded by Peach Bowl LegACy Fund and CURE Childhood Cancer.
(Press release, Moleculin, DEC 17, 2025, View Source [SID1234661504])