SEED Therapeutics Reports Tumor Eradication in a Neuroblastoma In Vivo Model with Clinical-Stage RBM39 Molecular Glue Degrader ST-01156
KING OF PRUSSIA, Pa., April 22, 2026 (GLOBE NEWSWIRE) -- SEED Therapeutics, Inc. (“SEED”), a clinical-stage biotechnology company pioneering rationally designed molecular glue degraders, today announced new data demonstrating potent anticancer activity of its RBM39 degrader program in neuroblastoma, a pediatric cancer with high unmet medical need. SEED’s scientific work also identified potential biomarkers predictive of anticancer response that will be further examined in the clinic, with Phase 1 dose escalation projected to be completed by Q1 2027. The findings are being presented at the 2026 Annual Meeting of the American Association for Cancer Research (AACR), which convenes more than 22,000 scientists, clinicians, and investors this week in San Diego.
ST-01156, SEED’s clinical-stage RBM39 molecular glue degrader, is currently being evaluated in a Phase 1 dose escalation study (NCT07197554) at six leading U.S. oncology centers.
Highlights At A Glance
Scientific Rationale: Why RBM39 Matters
RBM39 is an RNA-binding protein that governs pre-mRNA splicing — a process cancer cells exploit to fuel uncontrolled growth, evade cell death, and repair DNA damage. By degrading RBM39 entirely, rather than merely inhibiting it, SEED’s approach disrupts multiple oncogenic pathways simultaneously: cell cycle progression, metabolic reprogramming, DNA damage response, and programmed cell death (apoptosis — the process by which damaged or cancerous cells are eliminated by the body). This breadth of effect is a key differentiator from conventional targeted therapies.
Molecular glue degraders achieve this by redirecting the cell’s own quality-control machinery — the ubiquitin-proteasome system — to tag and destroy the target protein. SEED’s proprietary RITE3™ platform was designed from inception to identify, validate, and optimize molecular glues with a defined therapeutic window, bringing rational drug design to protein targets previously considered undruggable.
Key Data Highlights — AACR 2026 Poster #5785
“ST-01156’s advancement into clinical testing in 2026 marks a pivotal milestone for SEED and for patients with RBM39 dependent cancers, including neuroblastoma — a pediatric cancer with very limited effective treatment options. The identification of MYC and CDKN2A/B status as potential biomarkers is the product of SEED’s focus on identifying the patients who will significantly benefit from ST-01156.”
— James Tonra, PhD, President & Chief Scientific Officer, SEED Therapeutics
“The RBM39 data we are presenting at AACR 2026 reflect what SEED’s RITE3™ platform was designed to do — not just degrade a difficult target, but understand which patients are most likely to benefit. Seeing ST-01156 achieve complete tumor regression in a neuroblastoma model, at the same dosing schedule now in the clinic, is deeply gratifying and scientifically meaningful. Our focus at SEED is on ensuring that the molecular insight behind this program translates into real outcomes for patients with very few options.”
— Lan Huang, PhD, Co-Founder, SEED Therapeutics
Clinical Development Status
ST-01156 is being evaluated in an ongoing Phase 1 dose escalation study (NCT07197554) designed to establish safety, pharmacokinetics, and target engagement. The study enrolls patients enriched for cancer types with demonstrated RBM39 dependency in preclinical research. The trial is currently active at six leading U.S. oncology centers, with additional clinical sites in preparation. Phase 1 dose escalation is projected to be completed by Q1 2027. The dosing schedule employed is consistent with that used in IND-enabling studies and in the in vivo efficacy program reported at AACR 2026 — providing a robust translational foundation.
AACR 2026 Poster Presentation Details
Title: RBM39 Degrader Anticancer Activity Against Neuroblastoma; MYC and CDKN2A/B as Potential Response Biomarkers
Poster Number: 5785
Session: Proximity-Induced Drug Discovery 2 (Experimental and Molecular Therapeutics)
Authors: James Finn, Imad Salhab, Haihong Jin, Fei Liu, Dong Liu, Yunkai Zhang, Xing Liu, James Tonra, Lan Huang, Dan Lu
About SEED Therapeutics
SEED Therapeutics is a clinical-stage biotechnology company pioneering rationally designed molecular glue degraders to treat diseases driven by proteins previously considered undruggable. Its proprietary RITE3™ platform enables impactful targeted protein degradation with a defined therapeutic window, supporting a pipeline of six molecular glue programs across oncology, neurodegeneration, and immunology.
SEED was co-founded by four preeminent scientists:
Eli Lilly and Company and Eisai Co., Ltd. serve as cornerstone investors and cornerstone research collaborators, providing both capital validation and deep scientific partnership in support of SEED’s mission to unlock undruggable disease targets. Additional information is available at www.seedtherapeutics.com.
Forward-Looking Statements
This press release contains forward-looking statements, including statements regarding ongoing clinical trials, the potential of ST-01156, the utility of identified biomarkers, and SEED’s business strategy. These statements involve known and unknown risks and uncertainties that may cause actual results to differ materially. SEED undertakes no obligation to update forward-looking statements.
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