IDEAYA Biosciences and Hengrui Pharmaceuticals Announce Oral Presentation at IASLC 2025 World Conference on Lung Cancer for IDE849 (SHR-4849), a Potential First-in-Class DLL3-TOP1 ADC

• Clinical efficacy and safety data will be presented from over 70 small-cell lung cancer (SCLC) patients in Hengrui's ongoing, multi-site, open label Phase 1 trial
• Data will include patients from the dose escalation and at multiple expansion doses
• U.S. Phase 1 trial of IDE849 in SCLC patients initiated in 3Q 2025

JIANGSU, China and SOUTH SAN FRANCISCO, Calif., July 22, 2025 /PRNewswire/ -- IDEAYA Biosciences, Inc. (Nasdaq: IDYA), a leading precision medicine oncology company, and Jiangsu Hengrui Pharmaceuticals Co., Ltd. (Hengrui), a global pharmaceutical company focused on scientific and technological innovation, today announced the publication of an abstract for an oral presentation on IDE849 (SHR-4849) at the IASLC 2025 World Conference on Lung Cancer hosted by the International Association for the Study of Lung Cancer (WCLC), taking place September 6-9, 2025 in Barcelona, Spain. The presentation will cover efficacy and safety results in SCLC from the Phase 1 trial Hengrui is conducting in China for IDE849 (SHR-4849), a potential first-in-class delta-like ligand 3 (DLL3)-targeting Topoisomerase-1 (TOP1) payload antibody drug conjugate (ADC). DLL3 is upregulated across multiple solid tumor types where significant unmet need remains, including SCLC, neuroendocrine tumors (NETs), non-small cell lung cancer (NSCLC) and melanoma. 

IDEAYA will also have a poster presentation with data from a second published abstract providing combination mechanism and pre-clinical synergy data between TOP1-payload based ADCs and IDE161, the company's proprietary, potentially first-in-class PARG inhibitor. This combination has the potential to enhance the durability of TOP1-payload based ADCs, including IDE849 and IDE034, IDEAYA's B7H3/PTK7 bispecific TOP1 ADC, and aligns with the company's clinical development strategy of evaluating rational combinations, where appropriate, to drive improved clinical outcomes for patients with cancer.

"We are excited to have the first-in-human Phase 1 clinical efficacy and safety data presented by our partner Hengrui for IDE849 (SHR-4849) in SCLC patients at the WCLC 2025, as IDEAYA rapidly advances the global development of IDE849," said Dr. Darrin Beaupre, M.D., Ph.D., Chief Medical Officer, IDEAYA Biosciences. "IDE849 represents a potential first-in-class DLL3-TOP1 ADC, and we look forward to evaluating its clinical potential as both a monotherapy agent in SCLC and NET patients, as well as in combination with immunotherapy and our Phase 1 PARG inhibitor, IDE161," said Yujiro S. Hata, President and Chief Executive Officer, IDEAYA Biosciences. 

Details of the oral presentation are as follows:     

Title: A first-in-human Phase 1 study of SHR-4849 (IDE849), a DLL3-directed antibody drug conjugate (ADC) in relapsed SCLC     

Date and time: Sunday, September 7^th, 4:45-6:00 PM (CET)

Session: OA6 – Novel ADCs in SCLC

Details of the poster presentation are as follows:

Control #: 2165

Title: Dual PARG-TOP1 Inhibition Exacerbates DNA-Protein Crosslinks and Replication Stress: A Promising Strategy for Enhancing TOP1i-ADC Efficacy

Presenter: Reeja Maskey, Ph.D.

Date and time: Monday September 8th, 10:30 AM - 12:00 PM (CET)

Session: P2.10 - Metastatic Non-small Cell Lung Cancer – Antibody-Drug Conjugate and Cytotoxic Therapy

The oral presentation and poster will be available online at https://ir.ideayabio.com/events following the presentation.

About IDEAYA Biosciences

IDEAYA is a precision medicine oncology company committed to the discovery, development, and commercialization of transformative therapies to address unmet medical needs in cancer. The company integrates small molecule drug discovery, structural biology and bioinformatics with extensive capabilities in identifying and validating translational biomarkers to develop potentially first-in-class targeted therapies for selected patient populations. IDEAYA has built a robust pipeline of targeted therapies focused on synthetic lethality and antibody-drug conjugates, or ADCs, including bispecifics, with the goal of improving clinical outcomes for patients with cancer.

Forward-Looking Statements          

This press release contains forward-looking statements, including, but not limited to, statements related to (i) the potential therapeutic benefits of IDE849, including combination therapies; (ii) the timing and content of an oral presentation of the safety and efficacy data of IDE849 from a Phase 1 trial in SCLC; and (iii) the timing of and potential of clinical trials to evaluate TOP1-payload based ADCs in SCLC, NETs, and other DLL3-upregulated solid tumors, and in combination with IDE161/PARG to potentially enhance durability. Such forward-looking statements involve substantial risks and uncertainties that could cause IDEAYA's preclinical and clinical development programs, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in the drug development process, including IDEAYA's programs' early stage of development, the process of designing and conducting preclinical and clinical trials, the regulatory approval processes, the timing of regulatory filings, the challenges associated with manufacturing drug products, IDEAYA's ability to successfully establish, protect and defend its intellectual property, and other matters that could affect the sufficiency of existing cash to fund operations. IDEAYA undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of IDEAYA in general, see IDEAYA's Annual Report on Form 10-K dated February 18, 2025 and any current and periodic reports filed with the U.S. Securities and Exchange Commission.

Investor and Media Contact     

IDEAYA Biosciences
Joshua Bleharski, Ph.D.
Chief Financial Officer  
[email protected]

SOURCE IDEAYA Biosciences, Inc.