IDE-397

Phase 2/3 registrational trial (OptimUM-02) of darovasertib combination met its primary endpoint; complete data will be provided in a late-breaking oral presentation at ASCO IDEAYA to initiate RTOR submission process with first pre-submission in May; targeting completion of the NDA filing in H2 2026 Clinical updates from Phase 2 OptimUM-01 trial in HLA*A2-positive mUM, Phase 2 OptimUM-09 in neoadjuvant primary UM and Phase 1/2 trials with IDE849 (DLL3 TOP1 ADC) and IDE034 (B7H3/PTK7 bispecific TOP1 ADC) planned for H2 2026 Initiation of registrational trial for IDE849 monotherapy in DLL3-positive solid tumors planned by year-end 2026; Phase 1 combination cohort of IDE892 (PRMT5) + IDE397 (MAT2A) in MTAP-deleted cancers to begin in mid-2026 ~$973 million of cash, cash equivalents, and marketable securities as of March 31, 2026; current cash runway guidance into 2030 remains unchanged SOUTH SAN FRANCISCO, Calif., May 5, 2026 /PRNewswire/ -- IDEAYA Biosciences, Inc. (Nasdaq: IDYA), a leading precision medicine oncology company, provided a business update and announced financial results for the first quarter ended March 31, 2026. "This was a transformational quarter for IDEAYA, with positive topline results from the OptimUM-02 registrational trial in first line HLA*A2-negative metastatic uveal melanoma to enable the company's first NDA submission for potential U.S. accelerated approval. We look forward to a catalyst rich second half of 2026, including targeted clinical data updates for the darovasertib combination in HLA*A2-positive mUM, IDE849 in DLL3-positive solid tumors, and IDE034, our potential first-in-class B7H3/PTK7 bispecific TOP1 ADC, in multiple large solid tumor indications. Finally, clinical dose escalation is advancing rapidly for our potential first-in-class KAT6/7 dual inhibitor, IDE574, and our PRMT5 inhibitor, IDE892, with the goal of initiating clinical expansion and combination trials with IDE892 in MTAP-deleted PDAC and NSCLC in the second half of this year," said Yujiro S. Hata, President and Chief Executive Officer, IDEAYA Biosciences. Selected Pipeline Developments and Corporate Updates Darovasertib in Uveal Melanoma On April 13th IDEAYA reported positive topline data from the Phase 2/3 OptimUM-02 trial of darovasertib in combination with crizotinib (darovasertib combination) in first line (1L) HLA*A2-negative metastatic uveal melanoma (mUM). The trial met its primary endpoint, with the combination reducing the risk of disease progression by 58% (Hazard Ratio of 0.42; 95% CI: 0.30, 0.59; p-value: <0.0001) and achieving a statistically significant improvement in median progression-free survival (PFS) of 6.9 months versus 3.1 months in the investigator choice of therapy (ICT) arm as assessed by blinded independent central review (BICR). On secondary endpoints, an overall response rate (ORR) of 37.1%, including 5 complete responses, was observed in patients treated with the darovasertib combination versus 5.8% in the ICT arm (p-value: <0.0001) with a median duration of response (DOR) of 6.8 months. Overall survival (OS) data were not yet mature, however the darovasertib combination did show an early trend in OS improvement versus the ICT arm. The combination was generally well-tolerated with a manageable safety profile consistent with previously reported results and known side-effects of each drug. IDEAYA will provide complete data from the primary analysis of OptimUM-02 in a late-breaking oral presentation at the 2026 American Society of Clinical Oncology (ASCO) meeting in Chicago, Illinois, and plans to submit a manuscript for publication in the second half of 2026. A new drug application (NDA) submission to the U.S. Food and Drug Association (FDA) is planned in the second half of 2026 to support a potential U.S. accelerated approval. The FDA has agreed to review IDEAYA's NDA under the Oncology Center of Excellence (OCE) Real-Time Oncology Review (RTOR) program, which allows an applicant to pre-submit components of its NDA for review before the complete filing is submitted to provide a more efficient review process and ensure safe and effective treatments are available to patients as early as possible. IDEAYA has completed enrollment of approximately 100 HLA*A2-positive mUM patients in the single-arm Phase 2 OptimUM-01 trial of darovasertib in combination with crizotinib. The company plans to present data at a major medical conference from over 85 efficacy-evaluable HLA*A2-positive mUM patients in the second half of 2026. Data will include updated ORR, PFS, and OS results, which will be used to support a potential regulatory submission to the FDA to expand the labeled use of darovasertib and/or guideline inclusion to enable the use of the darovasertib combination in HLA*A2-positive mUM patients. In collaboration with Servier, IDEAYA successfully completed a Type C meeting with the U.S. FDA to align on the Phase 3 registrational design of the OptimUM-11 trial evaluating darovasertib in combination with crizotinib in the adjuvant setting of primary uveal melanoma. The trial will enroll approximately 450 primary uveal melanoma patients with increased risk of metastasis, irrespective of HLA status, randomized 1:1 to treatment with darovasertib combined with crizotinib for 12-months or observation. The primary endpoint is superiority by relapse-free survival (RFS). OptimUM-11 is a global trial being conducted as part of IDEAYA's partnership with Servier and is expected to initiate in the first half of 2026. IDEAYA is continuing site activation and patient enrollment in the Phase 3 OptimUM-10 trial of neoadjuvant darovasertib in primary uveal melanoma. Full enrollment in the trial is estimated to be complete by the end of 2027, revised from prior guidance of first half of 2027. IDEAYA is targeting to provide a clinical data update from the ongoing Phase 2 OptimUM-09 trial at a medical conference in the second half of 2026. ADC / DDR combinations IDE849 (DLL3 TOP1 ADC): targeting to provide a clinical data update from the ongoing IDEAYA-sponsored global Phase 1/2 trial of IDE849 in small-cell lung cancer (SCLC) and neuroendocrine carcinomas (NEC) by the end of 2026. The company is planning to initiate a monotherapy registrational trial by the end of 2026. In April, IDEAYA entered into a clinical collaboration agreement with AstraZeneca plc to evaluate the efficacy and safety of IDE849 in combination with Imfinzi® (durvalumab), a programmed death-ligand 1 (PD-L1) inhibitor, in extensive-stage SCLC. IDEAYA will sponsor the clinical combination trial; AstraZeneca will supply Imfinzi® at no cost. Achieved first-patient-in (FPI) in Phase 1 combination trial of IDE849 and IDE161, IDEAYA's proprietary inhibitor of poly(ADP-ribose) glycohydrolase (PARG). Data from this trial are intended to help evaluate the potential synergy between TOP1 and PARG inhibition to drive deeper, more durable anti-tumor responses in patients IDEAYA's China-region partner, Jinagsu Hengrui Pharmaceuticals Co. Ltd., is targeting to initiate Phase 3 registrational trials in China in 2027 for IDE849 in SCLC and provide a clinical update from their Phase 1 trial in SCLC and NEC at a medical conference in the second half of 2026. IDE034 (B7H3/PTK7 bispecific TOP1 ADC): achieved FPI in Phase 1 dose escalation trial to evaluate IDE034 in solid tumors, and is targeting to provide a clinical data update by the end of 2026. IDE034 is a potentially first-in-class B7H3/PTK7 bispecific TOP1 ADC designed to be internalized only when its target antigens are co-expressed on the same tumor cell, which may enhance its selectivity and tolerability profile relative to monovalent antibody formats. Patient dosing triggered a $5 million milestone payment from IDEAYA to Biocytogen, pursuant to the Option and License Agreement between the companies. MTAP pathway IDE892 (PRMT5): achieved FPI in Phase 1 dose escalation trial of IDE892 in MTAP-deleted solid tumors, including non-small cell lung cancer (NSCLC) and pancreatic ductal adenocarcinoma (PDAC). IDEAYA is planning to initiate a Phase 1 combination cohort with IDE397, its proprietary MAT2A inhibitor, in MTAP-deleted cancers in mid-2026 and expansion in the second half of 2026. Dual inhibition of IDE892 and IDE397 has demonstrated durable and well-tolerated tumor regressions in preclinical MTAP-deleted tumor models, including in NSCLC. In March, IDEAYA announced it will deprioritize clinical activity with Gilead evaluating the combination of IDE397 and Trodelvy and conclude enrollment in the Phase 1/2 trial in MTAP-deleted urothelial and lung cancers. Other programs IDE574 (KAT6/7): achieved FPI in Phase 1 dose escalation trial of IDE574 in solid tumors including breast, prostate, colorectal and lung cancer. IDE574 is a selective, equipotent dual inhibitor of both KAT6 and KAT7 which spares other structurally similar paralogs, including KAT5 and KAT8, which are required for normal cell function. KAT6 and KAT7 are epigenetic modulators of cell identity and lineage commitment programs that are corrupted by oncogenic transformation. Following termination of the Collaboration, Option and License Agreement with GlaxoSmithKline in 2025, IDEAYA plans to discontinue development of IDE275, a small molecule inhibitor of Werner helicase (WRN), and IDE705, a small molecule inhibitor of Pol-Theta helicase (POLQ). The company is currently evaluating strategic options for these assets. Corporate In February, IDEAYA announced the appointment of Dr. Theodora (Theo) Ross into the newly created role of Chief Development Officer. Dr. Ross will be responsible for leading early clinical development for IDEAYA's emerging oncology pipeline and play a crucial role in guiding the company's long-term R&D strategy. She joins IDEAYA from AbbVie, where she served as Vice President, Head of Early Oncology R&D and Site Head for the Bay Area. As of March 31, 2026, IDEAYA had $972.9 million of cash, cash equivalents and marketable securities; current cash runway guidance into 2030 remains unchanged. Financial Results for the Quarter Ended March 31, 2026 As of March 31, 2026, IDEAYA had cash, cash equivalents and marketable securities of approximately $972.9 million, compared to $1.05 billion as of December 31, 2025. The decrease was primarily driven by net cash used in operations. Collaboration revenue for the three months ended March 31, 2026, totaled $6.6 million compared to $10.9 million for the three months ended December 31, 2025. Collaboration revenue was recognized for the performance obligations satisfied through March 31, 2026 related to the research and development services that are recognized over time under the Servier exclusive license agreement for darovasertib. As of March 31, 2026, the remaining balance for the research and development services performance obligations is $155.3 million related to the clinical development cost reimbursements anticipated under the license agreement that will be recognized as IDEAYA collaboration revenue over time as the research and development services are completed. Research and development (R&D) expenses for the three months ended March 31, 2026 totaled $95.7 million compared to $86.6 million for the three months ended December 31, 2025. The increase was primarily driven by higher clinical trial and personnel-related expenses to support our programs. General and administrative (G&A) expenses for the three months ended March 31, 2026 totaled $19.4 million compared to $18.8 million for the three months ended December 31, 2025. The increase was primarily due to higher personnel-related expenses to support company growth and darovasertib commercial preparation activities. The net loss for the three months ended March 31, 2026, was $98.5 million compared to the net loss of $83.3 million for the three months ended December 31, 2025. Total stock compensation expense for the three months ended March 31, 2026, was $14.5 million compared to $11.8 million for the three months ended December 31, 2025. About IDEAYA Biosciences IDEAYA is a precision medicine oncology company committed to the discovery, development, and commercialization of transformative therapies for cancer. Our approach integrates expertise in small-molecule drug discovery, structural biology and bioinformatics with robust internal capabilities in identifying and validating translational biomarkers to develop tailored, potentially first-in-class targeted therapies aligned to the genetic drivers of disease. We have built a deep pipeline of product candidates focused on synthetic lethality and antibody-drug conjugates, or ADCs, for molecularly defined solid tumor indications. Our mission is to bring forth the next wave of precision oncology therapies that are more selective, more effective, and deeply personalized with the goal of altering the course of disease and improving clinical outcomes for patients with cancer. IDEAYA's corporate presentation is available on its website: . Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other applicable securities laws. All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including, without limitation, statements regarding IDEAYA Biosciences, Inc.'s ("IDEAYA") expectations with respect to the timing, progress, and results of its clinical trials and preclinical programs; the potential safety, efficacy, and therapeutic benefits of its product candidates; the planned presentation and publication of clinical data; the timing and likelihood of regulatory submissions, including the planned new drug application (NDA) for darovasertib and participation in the FDA's Real-Time Oncology Review (RTOR) program; the potential for accelerated approval and label expansion; the initiation, design, and enrollment of current and future clinical trials; the development and advancement of IDEAYA's pipeline programs, including IDE849, IDE034, IDE892, IDE397, and IDE574; the expected timing of clinical updates and milestones; the potential benefits of collaborations; and IDEAYA's financial position, including its expected cash runway. These forward-looking statements are based on management's current expectations and assumptions and are subject to a number of risks, uncertainties, and other factors that could cause actual results to differ materially from those described in the forward-looking statements. Such risks and uncertainties include, but are not limited to: risks related to the timing, progress, and results of clinical trials and preclinical studies; the ability of IDEAYA to obtain and maintain regulatory approvals; uncertainties regarding the regulatory review process, including participation in the RTOR program; the potential for clinical data to differ from preliminary or interim results; the ability to successfully develop, manufacture, and commercialize product candidates; competition from other biotechnology and pharmaceutical companies; the impact of global economic conditions; 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 and other risks described in IDEAYA's filings with the U.S. Securities and Exchange Commission (SEC), including its most recent Quarterly Report on Form 10-Q and Annual Report on Form 10-K. Forward-looking statements speak only as of the date of this press release, and IDEAYA undertakes no obligation to update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise, except as required by law. Investor and Media Contact IDEAYA Biosciences Joshua Bleharski, Ph.D. Chief Financial Officer [email protected] SOURCE IDEAYA Biosciences, Inc. 21% more press release views with Request a Demo

SAN DIEGO, April 22, 2026 /PRNewswire/ -- Abbisko Therapeutics (HKEX: 02256) announced that the company presented six latest preclinical and translational research findings in poster sessions at the American Association for Cancer Research (AACR) Annual Meeting, held from April 17 to 22, 2026, in San Diego, USA. The presentations span multiple key innovation areas, including the pan-KRAS inhibitor ABSK211, the 4 th generation EGFR inhibitor ABK-EGFR-1, the CDK4 selective inhibitor ABK-CDK4, the MTA-cooperative PRMT5 inhibitor ABSK131, as well as a ctDNA-based study investigating resistance mechanisms to the FGFR2/3 inhibitor ABSK061. pan-KRAS Inhibitor ABSK211 ABSK211 is a potent, highly selective, and orally bioavailable small-molecule pan-KRAS inhibitor developed by Abbisko Therapeutics. It demonstrates broad inhibitory activity against multiple KRAS mutations, addressing significant unmet medical needs in KRAS-driven cancers. At AACR 2026, Abbisko presented preclinical data for both monotherapy and combination strategies of ABSK211. Monotherapy: Broad and Potent Inhibition Across KRAS Mutations KRAS mutations are highly prevalent across multiple cancers, including pancreatic (~90%), colorectal (~35%), and lung cancer (~25%). While several pan-KRAS inhibitors have entered clinical development, there remains a critical need for enhanced potency. In preclinical studies, ABSK211 demonstrated: Robust in vitro activity: ABSK211 significantly reduced cell viability across multiple KRAS alterations (including G12, G13, Q61, and WT amplification) at sub-nanomolar to nanomolar concentrations. Meanwhile ABSK211 displayed marginal inhibition in KRAS wild-type cell line with normal copy. Strong in vivo efficacy: Oral administration induced deep tumor regression in multiple KRAS G12V xenograft models, with robust target engagement. Broad mutation coverage: Consistent and significant antitumor activity was observed in models harboring KRAS G12D/C/S and G13D mutations. These findings support the clinical advancement of ABSK211, which is currently undergoing IND-enabling studies. Poster Information Title: Preclinical characterization of ABSK211: A highly potent, orally bioavailable and selective pan-KRAS inhibitor with broad and robust activity in KRAS-driven tumors Time: April 22, 2026, 9:00 AM – 12:00 PM (PT) Location: Poster Section 13, Board #10 Abstract #: 7090 Combination Therapy: Multi-Mechanistic Synergy Enhances Antitumor Activity Combination therapy is widely considered a key strategy to improve treatment outcomes in KRAS-mutant cancers. ABSK211 demonstrated synergistic antitumor activity with multiple therapeutic agents: In vitro synergy: Significant anti-proliferative synergy with PRMT5 inhibitors across KRAS mutations; strong synergy observed with EGFR monoclonal antibodies and chemotherapy in KRAS G12D/G12V models. Enhanced in vivo efficacy: Combination regimens with PRMT5 inhibitors, cetuximab, immunotherapies, and chemotherapy showed superior tumor growth inhibition and improved durability compared to monotherapy. These results demonstrate that ABSK211 can significantly enhance antitumor efficacy through multi-mechanistic synergy, supporting its further development in combination strategies. Poster Information Title: ABSK211, a highly potent and orally available pan-KRAS inhibitor, demonstrates robust antitumor efficacy in combination with multiple agents Time: April 22, 2026, 9:00 AM – 12:00 PM (PT) Location: Poster Section 13, Board #3 Abstract #: 7083 4 th Generation EGFR Inhibitor ABK-EGFR-1 ABK-EGFR-1 is a novel 4th generation EGFR inhibitor developed by Abbisko Therapeutics, specifically designed to target the EGFR C797S resistance mutation. It combines high selectivity with central nervous system (CNS) penetration to address key clinical challenges following resistance to 3rd generation EGFR TKIs. Targeting C797S-Mediated Resistance The EGFR C797S mutation is a clinically validated mechanism of resistance to third-generation EGFR TKIs, with an estimated 51,000–146,000 cases annually worldwide. Currently, no approved therapies specifically target this mutation, representing a significant unmet clinical need. Preclinical studies showed that ABK-EGFR-1: Exhibits high selectivity over wild-type EGFR and other kinases. Demonstrates significant in vivo antitumor activity in multiple EGFR C797S-driven xenograft models, effectively inhibiting tumor growth. Possesses excellent blood-brain barrier penetration and favorable drug-like properties. These findings support further development of ABK-EGFR-1 as a next-generation targeted therapy for EGFR-resistant cancers, particularly for patients with brain metastases. Poster Information Title: Discovery and characterization of ABK-EGFR-1, a 4th generation EGFR C797S Inhibitor with excellent selectivity and brain penetration Time: April 21, 2026, 2:00 PM – 5:00 PM (PT) Location: Poster Section 53, Board #7 Abstract #: LB350 CDK4 Selective Inhibitor ABK-CDK4 ABK-CDK4 is a highly selective, brain-penetrant small-molecule CDK4 inhibitor developed by Abbisko Therapeutics. It is designed to selectively target CDK4, reduce CDK6-related toxicity, and expand treatment potential for patients with brain metastases. Differentiation Through Selectivity and CNS Penetration 1st generation CDK4/6 inhibitors (e.g., palbociclib, ribociclib, and abemaciclib) have demonstrated clinical benefit in breast cancer, but CDK6 inhibition is associated with dose-limiting hematologic toxicities. In addition, 20–40% of breast cancer patients develop brain metastases, while current therapies have limited CNS exposure. Preclinical studies showed that ABK-CDK4: High selectivity: Over 50-fold selectivity for CDK4 versus CDK6, potentially reducing CDK6-related toxicity. CNS penetration: Favorable CNS exposure (Kpuu > 0.5) and drug-like properties. Antitumor activity: Effective inhibition of Rb phosphorylation and tumor growth in HR+/HER2− breast cancer models These results suggest that ABK-CDK4 may overcome key limitations of current CDK4/6 inhibitors and provide a differentiated therapeutic option. Poster Information Title: Discovery of ABK-CDK4, a selective and brain-penetrant CDK4 inhibitor Time: April 20, 2026, 9:00 AM - 12:00 PM (PT) Location: Poster Section 20, Board #13 Abstract #: 1905 MTA-cooperative PRMT5 inhibitor ABSK131 ABSK131 is a potent and selective small-molecule MTA-cooperative PRMT5 inhibitor developed by Abbisko Therapeutics, targeting MTAP-deleted tumors, and is currently in clinical development. Broad Synergy Across Multiple Therapeutic Modalities MTAP homozygous deletion occurs in approximately 10–15% of solid tumors and frequently co-exists with oncogenic drivers such as KRAS and EGFR. In addition, MTAP abnormities are associated with poor prognosis following standard-of-care therapies across multiple cancer types. Therefore, there remains a significant unmet need for novel and effective combination therapies centered on MTA-cooperative PRMT5 inhibitor for MTAP-deleted tumors, with the potential to enable precision patient stratification and deliver synergistic therapeutic benefits. Preclinical studies demonstrated that ABSK131 exhibits strong synergistic activity with multiple therapies: KRAS inhibitors: Enhanced tumor growth inhibition in KRAS-mutant, MTAP-deleted models when combined with AMG 510 or ABSK141. EGFR inhibitors: Improved anti-proliferative and in vivo antitumor activity in EGFR-mutant, MTAP-deleted NSCLC models when combined with osimertinib. MAT2A inhibitors: Consistent synergistic effects across multiple tumor models when combined with IDE397. Chemotherapy: Synergistic activity observed both in vitro and in vivo when combined with carboplatin in NSCLC models. These findings support ABSK131 as a potential backbone therapy for combination strategies in MTAP-deleted tumors. Poster Information Title: Synergistic antitumor activity of the MTA-cooperative PRMT5 inhibitor ABSK131 in combination with multiple therapeutic agents in diverse cancer models Time: April 21, 2026, 9:00 AM - 12:00 PM (PT) Location: Poster Section 14, Board #23 Abstract #: 4504 FGFR2/3 Inhibitor ABSK061 ABSK061 is a highly potent and selective small-molecule FGFR2/3 inhibitor developed by Abbisko Therapeutics. It has demonstrated encouraging efficacy and safety in Phase I studies and is currently being evaluated in a Phase II trial for gastric cancer. ctDNA Analysis Reveals Resistance Mechanisms Acquired resistance remains a major challenge limiting the long-term benefit of targeted therapies. Using ctDNA-based next-generation sequencing (NGS), Abbisko conducted longitudinal genomic analyses comparing baseline and progression samples to elucidate resistance mechanisms to ABSK061: On-target resistance: Polyclonal acquired FGFR2 mutations in the FGFR2 kinase domain were commonly observed in gastric cancer and cholangiocarcinoma. Off-target resistance: FGFR2-Atered NSCLC was prone to develop acquired alterations in genes involved in RTK/RAS pathways. These findings provide important molecular insights into resistance mechanisms and inform the design of future combination and sequential treatment strategies. Poster Information Title: Circulating tumor DNA (ctDNA)-based profiling of acquired resistance to the fibroblast growth factor receptor (FGFR)2/3 inhibitor lavengratinib(ABSK061) in patient(pt)s with advanced solid tumors Time: April 21, 2026, 9:00 AM - 12:00 PM (PT) Location: Poster Section 45, Board #14 Abstract #: 5319 At AACR 2026, Abbisko Therapeutics showcased the latest preclinical and translational research advances across multiple pipeline programs, demonstrating its strong capabilities in drug discovery and development. As these programs continue to advance into clinical stages, the company is further strengthening its globally competitive R&D platform. Looking ahead, Abbisko Therapeutics will continue to focus on addressing unmet medical needs and accelerating the translation of innovative discoveries into clinical applications, with the goal of delivering more first-in-class and best-in-class therapies to patients worldwide. 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