BridGene Biosciences to Present Three Posters at the 2025 AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics

--Discovery of a Novel Covalent FGFR3 Inhibitor with Potent Anti-Cancer Activity

--Discovery of a First-in-Class Covalent PAX8 Inhibitor Targeting the DNA-Binding Domain

--Broad Application of IMTAC™ Chemoproteomics to Identify Covalent Ligandable Sites Across the Proteome

SAN JOSE, Calif., Oct. 23, 2025 /PRNewswire/ -- BridGene Biosciences, Inc., a leader in the discovery of small molecule drugs for traditionally "hard-to-drug" targets, announced today that three abstracts have been accepted for presentation at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics, taking place October 22-26, 2025, in Boston, Massachusetts. The presentations showcase new discoveries from BridGene's proprietary IMTAC™ (Isobaric Mass Tagged Affinity Characterization) chemoproteomics platform, including the identification of a novel covalent FGFR3 inhibitor, a first-in-class PAX8 inhibitor, and data illustrating the breadth and precision of IMTAC™ in mapping covalent ligandable sites across the proteome.

BridGene will present findings from its study titled "Discovery of a Highly Potent and Selective Covalent FGFR3 Inhibitor," which details the identification and preclinical evaluation of a selective FGFR3 inhibitor discovered using the company's IMTAC™ chemoproteomics platform. The compound demonstrated irreversible binding to a previously uncharacterized cysteine residue in FGFR3, resulting in sustained inhibition of FGFR3 phosphorylation and downstream ERK signaling. In cellular models harboring FGFR3 alterations, the inhibitor exhibited nanomolar potency and strong antiproliferative effects, while maintaining high selectivity over other FGFR family members. These data support the potential of covalent FGFR3 inhibition as a novel therapeutic strategy for FGFR3-driven cancers and further validate BridGene's chemoproteomic approach for uncovering druggable sites in challenging targets.

BridGene will present findings from its study titled "IMTAC™: A Proteome-Wide Live-Cell Screening Platform for Discovering Covalent Binders to Diverse Targets Including GPCRs, Phosphatases, and More." The research showcases how BridGene's proprietary IMTAC™ platform integrates a highly diverse covalent small molecule library with advanced live-cell chemical proteomics and quantitative mass spectrometry to identify direct, on-target binding events under native cellular conditions. The platform enables proteome-wide selectivity profiling, minimizes false positives, and reveals transient, novel binding pockets that are undetectable in traditional assays.

Using IMTAC™, BridGene identified covalent binders across multiple challenging target classes, including GPCRs, phosphatases, and kinases. In GPCR studies, BGP-1951 inhibited serotonin-induced calcium influx through 5-HT₂A while avoiding common CNS toxicity profiles, and BGP-2992 acted as a positive allosteric modulator of CXCR4 signaling with therapeutic potential in neuroinflammation. Among phosphatases, BGP-15341 inhibited ENPP1 enzymatic activity at nanomolar potency, and BGP-1900 selectively bound PTPN2, offering a path toward targeted degradation strategies. In kinase assays, BGP-21172 showed strong selectivity for CDK7, and two ADK binders—BGP-1892 and BGP-13486—demonstrated nanomolar activity in target engagement assays.

BridGene will present findings from "Discovery of a Covalent Inhibitor Targeting PAX8-Driven Ovarian Cancer" highlighting the identification of BGP-31609, a covalent small molecule inhibitor discovered through the IMTAC™ platform. BGP-31609 binds irreversibly to a single cysteine residue within the DNA-binding domain of PAX8, disrupting transcriptional activity and reducing the expression of downstream oncogenic targets including FGF18 and CCNA2. In biochemical and cellular assays, the compound showed dose-dependent inhibition of DNA binding in EMSA and selective suppression of PAX8-driven luciferase activity with minimal off-target effects. Importantly, BGP-31609 inhibited proliferation of PAX8-high OVCAR3 ovarian cancer cells while sparing PAX8-negative A549 cells, demonstrating target selectivity. These results establish BGP-31609 as a validated covalent binder to an historically undruggable transcription factor and a promising lead for treating PAX8-dependent malignancies.

"We're excited to share these new discoveries that further validate the strength and versatility of our IMTAC™ chemoproteomics platform," stated Ping Cao, Ph.D., CEO and co-founder of BridGene Biosciences. "The data we're presenting at AACR-NCI-EORTC illustrate how IMTAC™ can uncover previously hidden binding sites and enable the development of covalent inhibitors against some of the most challenging oncology targets. These findings reflect our commitment to expanding what's possible in small molecule drug discovery and to translating this science into meaningful therapies for patients."

The three poster presentations will be available on the AACR-NCI-EORTC conference website following the sessions. BridGene's scientific team will be available to discuss the data and the continued advancement of the company's IMTAC™ platform in driving discovery of covalent small molecule drugs for previously undruggable targets.

About BridGene Biosciences

BridGene is a biotechnology company focused on discovering and developing innovative small molecules that drug traditionally undruggable targets, providing new paths to treat diseases. By using its proprietary chemoproteomic platform, IMTAC™, BridGene can screen small molecules against all proteins in live cells to discover drug candidates for high-value and previously undruggable targets. BridGene is advancing a diversified pipeline of first-in-class drugs for targets in multiple disease areas. For more information, visit https://bridgenebio.com/.

Contact
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Jonathan Nugent (investors)
205-566-3026
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Eric Reiss (media)
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SOURCE BridGene Biosciences