IDEAYA Biosciences, Inc. (Nasdaq: IDYA) has announced that its Werner Helicase (WRN) inhibitor IDE275 (GSK959) will be featured in an oral presentation at the prestigious New Drugs on the Horizon series at the American Association for Cancer Research (AACR) Annual Meeting in Chicago this April. The presentation highlights the compound's potential as a breakthrough therapy for high microsatellite instability (MSI-H) solid tumors.
IDE275, developed in partnership with GSK, is currently advancing through Phase 1 dose escalation trials. The drug has demonstrated what researchers describe as a "potential best-in-class preclinical profile" in treating MSI-H cancers, with a binding mechanism distinct from previously reported WRN inhibitors.
Targeting a Significant Patient Population
MSI-H status represents a meaningful biomarker-defined population with significant prevalence across multiple cancer types. According to reported data, MSI-H is present in approximately 31% of endometrial cancers, 20% of colorectal cancers, and 19% of gastric cancers, indicating a substantial patient population that could benefit from this targeted approach.
"IDE275 (GSK959) has a potential best-in-class profile and the preclinical data to be presented at AACR 2025 with GSK highlights the molecule's selectivity to treat MSI-H solid tumors and potential to be developed clinically as both a monotherapy agent and in combination with PD1," said Yujiro S. Hata, President and Chief Executive Officer of IDEAYA Biosciences.
Michael White, Ph.D., Chief Scientific Officer at IDEAYA, added, "By binding uniquely to the helicase domain of WRN, IDE275 (GSK959) delivers potent and selective inhibition across MSI-H models."
Impressive Preclinical Results
Preclinical studies have demonstrated IDE275's efficacy, inducing single-agent tumor regressions in MSI-H patient-derived xenograft (PDX) and cell line-derived xenograft (CDX) models for endometrial, colorectal, and gastric cancers. These results suggest potential clinical applications across multiple cancer types characterized by the MSI-H biomarker.
The oral presentation, titled "An innovative and reversible WRN helicase inhibitor, GSK4418959 (IDE275), emerges as a promising clinical candidate for MSI-H cancers," will be delivered by Dr. Yanhua Rao from GSK on Monday, April 28, 2025.
Extensive Presence at AACR 2025
IDEAYA will have a significant presence at AACR 2025 with eight total presentations spanning three clinical and two pre-clinical programs. In addition to the four presentations on IDE275 (GSK959), the company will present data on its IDE397/MAT2A, IDE161/PARG, PRMT5, and KAT6/7 programs.
The three poster presentations on IDE275 will cover:
- Patient selection, target engagement, and pharmacodynamic markers
- Preclinical characterization demonstrating potency, selectivity, and efficacy across MSI-H tumors
- The drug's discovery and development as a novel, non-covalent, reversible WRN inhibitor
Collaboration Terms with GSK
The IDE275 program is advancing under a collaboration agreement between IDEAYA and GSK. Under this partnership, GSK is responsible for 80% of global research and development costs, while IDEAYA covers the remaining 20%. GSK holds a global, exclusive license to develop and commercialize the drug.
The financial terms of the agreement are substantial. IDEAYA stands to earn a $10 million milestone payment upon initiation of Phase 1 clinical dose expansion, with eligibility to receive up to $465 million in future late-stage development and regulatory milestone payments. Upon commercialization, the company could receive up to $475 million in commercial milestones, 50% of U.S. net profits, and tiered royalties on global non-U.S. net sales ranging from high single-digit to sub-teen double-digit percentages.
Synthetic Lethality Approach
IDE275 represents IDEAYA's commitment to synthetic lethality, an emerging class of precision medicine targets. This approach exploits specific genetic vulnerabilities in cancer cells, allowing for targeted treatment with potentially fewer side effects compared to traditional chemotherapy.
The company's focus on precision medicine oncology integrates capabilities in identifying and validating translational biomarkers with drug discovery to select patient populations most likely to benefit from its targeted therapies.
As the Phase 1 trial progresses, the oncology community will be watching closely to see if IDE275's clinical performance matches its promising preclinical profile. If successful, this WRN inhibitor could represent an important new treatment option for patients with MSI-H cancers, addressing a significant unmet medical need in precision oncology.
All presentations from AACR 2025 will be available online at IDEAYA's investor relations website following the conference.
