SEED Therapeutics Doses First Patient in Phase 1 Trial of ST-01156, a Molecular Glue Degrader Targeting RBM39

First-in-human study evaluates safety, pharmacokinetics, biomarker analyses, target engagement, and anti-tumor activity in patients with advanced solid tumors

ST-01156 has received U.S. FDA Orphan Drug Designation and Rare Pediatric Disease Designation

KING OF PRUSSIA, Pa., Jan. 09, 2026 (GLOBE NEWSWIRE) -- SEED Therapeutics, Inc. (“SEED”), a clinical-stage biotechnology company specializing in molecular glue degraders, today announced the dosing of the first patient in its Phase 1a dose-escalation study of ST-01156, an oral RBM39 degrader, in patients with advanced solid tumors. The initial component of this clinical trial allows enrollment of patients with any form of advanced solid tumor malignancy while enriching for cancer types with strong preclinical evidence of RBM39-dependency, including Ewing sarcoma, KRAS-mutant cancers, and hepatocellular carcinoma.

ST-01156 is an orally administered, brain-penetrant molecular glue degrader designed to selectively degrade RBM39, a key regulator of RNA splicing and transcription required for the survival of several cancer types. In preclinical studies, ST-01156 demonstrated robust target engagement, anti-tumor activity, and a favorable safety profile, including complete tumor regression in animal models of Ewing sarcoma and KRAS-mutant colorectal cancer. ST-01156 has received U.S. FDA Orphan Drug Designation and Rare Pediatric Disease Designation for the treatment of Ewing sarcoma, where no new therapeutic agent has been approved in the last 30 years.

“Dosing the first patient with ST-01156 marks an important milestone for SEED and for patients with cancers that urgently need new therapeutic options,” said Dr. Lan Huang, PhD, Co-Founder, Chair, and Chief Executive Officer of SEED Therapeutics. “We believe RBM39 degradation represents a powerful and differentiated therapeutic strategy, and we look forward to advancing this program through clinical development.”

“This trial is thoughtfully designed to build on the powerful preclinical signals of safety and efficacy while integrating PK, PD, and biomarker learning from the outset, with the goal of learning from each patient to optimize therapeutic development,” said George Demetri, MD, Professor of Medicine at Harvard Medical School and Dana-Farber Cancer Institute, and Chair of SEED Scientific Advisory Board. “The initiation of clinical dosing brings us one step closer to translating the novel mechanism of ST-01156 action into meaningful benefit for patients.”

In the Phase 1a study, ST-01156 will be administered orally, once daily for 5 days every 7 days, for 28 consecutive days. The primary objective of the open-label, first-in-human trial is to evaluate the safety, tolerability, and adverse event profile of ST-01156, as well as to identify the recommended dose level for subsequent clinical development. Secondary objectives include the characterization of pharmacokinetics and preliminary evidence of anticancer activity. Exploratory objectives include the demonstration of target engagement in circulating cells in blood. Please visit ClinicalTrials.gov (NCT07197554) for additional information, including the study design, outcome measures, and participating locations, which currently include Dana-Farber Cancer Institute, Memorial Sloan Kettering Cancer Center, MD Anderson Cancer Center, Mass General Hospital, City of Hope, and Hoag Cancer Center.

About SEED Therapeutics
SEED Therapeutics is a clinical-stage biotechnology company pioneering rationally designed molecular glue degraders to treat diseases driven by undruggable proteins. Its proprietary RITE3™ platform enables targeted protein degradation with small-molecule precision.

SEED Therapeutics was co-founded by four scientific leaders:

• Nobel Laureate Prof. Avram Hershko, discoverer of the ubiquitin-proteasome system
• Dr. Lan Huang, solved the first E3 Ligase structure and a serial biotech entrepreneur
• Prof. Ning Zheng (University of Washington, HHMI Investigator), pioneer of RING-finger E3 Ligase structures and coined the term “molecular glue”
• Prof. Michele Pagano (NYU Grossman School of Medicine, HHMI Investigator), a preeminent expert on E3 ligase biology

Eli Lilly and Co. and Eisai Co., Ltd., are cornerstone investors and research collaborators, supporting SEED’s mission to unlock undruggable disease targets. The company’s pipeline includes six molecular glue programs across oncology, neurodegeneration, immunology, and virology.

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