GNAQ

Enrollment in darovasertib + crizotinib 1L HLA-A2+ MUM potential Ph2/3 registration-enabling trial is ahead of schedule and has exceeded 150 patients Successful FDA Type C meeting and targeting initiation of Ph3 registration-enabling trial for darovasertib in neoadjuvant UM in H1 2025; Phase 2 neoadjuvant update with ~49% with >30% ocular tumor shrinkage & ~61% eyes preserved, and over 75 patients enrolled ENA 2024: Late-breaker oral presentation of IDE397 in MTAP-deletion UC and NSCLC with confirmed ORR by RECIST 1.1 of 40%, 38%, and 22%, in UC, SqNSCLC, and AdenoNSCLC, respectively; co-published IDE397 + AMG 193 preclinical combo data in MTAP-deletion IDE397 + AMG 193 combination study ongoing in MTAP-deletion solid tumors, and targeting expansion in MTAP-deletion NSCLC in late 2024 to early 2025 Targeting expansion of Phase 1/2 study of IDE397 in combination with Trodelvy® in MTAP-deletion UC in Q4 2024, and PR reported at ENA 2024 has confirmed by RECIST 1.1 Targeting Phase 1/2 expansion for IDE161 and FPI in combination with Merck's anti-PD-1 therapy KEYTRUDA® (pembrolizumab) in MSI-High and MSS EC in Q4 2024 IDE705 (GSK 101) Pol Theta Helicase Phase 1 dose escalation ongoing in HRD solid tumors Received IND clearance for IDE275 (GSK959) Werner Helicase development candidate ($7.0 million milestone) for Phase 1 trial in MSI-High solid tumors Targeting Development Candidate nomination for MTAP-deletion, KAT6 pathway and B7H3/PTK7 Topo-Payload Bispecific-ADC programs in Q4 2024 Targeting Investor R&D Day on Monday, December 16, to highlight IDEAYA's preclinical and clinical pipeline with leading KOL(s) and Pharma partner(s) $1.2 billion of cash, cash equivalents and marketable securities as of September 30, 2024, anticipated to fund operations into at least 2028; Completed an oversubscribed ~$302.4 million follow-on financing in July 2024 SOUTH SAN FRANCISCO, Calif., Nov. 4, 2024 /PRNewswire/ -- IDEAYA Biosciences, Inc. (Nasdaq: IDYA), a precision medicine oncology company committed to the discovery and development of targeted therapeutics, provided a business update, and announced financial results for the third quarter ended September 30, 2024. "This was a transformational quarter for IDEAYA, including completion of an oversubscribed ~$302.4 million follow-on financing, a late breaker oral presentation at ENA 2024 for IDE397 in heavily pre-treated MTAP-deletion urothelial and lung cancer patients, and a successful Type C meeting with the FDA to enable a potential registration-enabling trial for darovasertib in neoadjuvant uveal melanoma. Next, we received IND clearance for Werner Helicase inhibitor IDE275 with our partner GSK, representing our fifth potential first-in-class clinical program," said Yujiro S. Hata, Chief Executive Officer and Founder, IDEAYA Biosciences. "We continue to execute on our strategic vision to build a leading precision medicine oncology pipeline, and are on track to nominate our 6th, 7th, and 8th development candidate by year-end, including from our B7H3/PTK7 bi-specific topo-ADC, MTAP-deletion, and KAT6 pathway programs. We look forward to highlighting IDEAYA's potential first-in-class preclinical and clinical programs, and to continue to establish our scientific leadership in precision medicine oncology at our upcoming investor R&D day," said Michael White, Ph.D., Chief Scientific Officer, IDEAYA Biosciences. "This past quarter, we made significant progress on the darovasertib program, including being ahead of our enrollment targets for the first-line MUM potential registration-enabling trial, and a successful Type C meeting with the FDA to inform a potentially registration-enabling trial in the neoadjuvant uveal melanoma setting. Next, the clinical data update from ENA 2024, provides further clinical proof-of-concept for IDE397 at the RP2D in MTAP-deletion urothelial and lung cancer. We are excited to advance our broader IDE397 rational combination strategy, including target expansion with AMG 193 in MTAP-deletion NSCLC in late 2024 to early 2025, and target expansion with Trodelvy® (sacituzumab govitecan-hziy), Gilead's Trop-2 directed antibody-drug conjugate, in MTAP-deletion urothelial cancer in the fourth quarter. Lastly, we are targeting to select a monotherapy expansion dose for IDE161, and achieve FPI in combination with Keytruda in MSI-High and MSS endometrial cancer by year-end," added Darrin Beaupre, M.D., Ph.D., Chief Medical Officer, IDEAYA Biosciences. Summary of Q3 and Recent Key Developments Research and Clinical Development Darovasertib in 1L MUM and Neoadjuvant Uveal Melanoma (UM) Enrollment in darovasertib + crizotinib 1L HLA-A2+ MUM potential Ph2/3 registration-enabling trial is ahead of schedule and has exceeded 150 patients Positive interim Phase 2 results of darovasertib (IDE196) from the company-sponsored and investigator-sponsored trials (IST) were highlighted during an Investor Webcast in September 2024, and over 75 patients have been enrolled in company-sponsored trial. Following a successful Type C meeting with the U.S. Food and Drug Administration (FDA), IDEAYA is finalizing the Phase 3 registrational trial protocol and is targeting to initiate its potential registration-enabling trial in the first half of 2025. IDE397 in MTAP-Deletion Solid Tumors Phase 1 expansion results of IDE397 in 27 evaluable MTAP-deletion urothelial cancer (UC) and non-small cell lung cancer (NSCLC) patients were presented as a late-breaking oral presentation at the 36th EORTC-NCI-AACR Symposium (ENA 2024) in Barcelona, Spain. Additional preclinical data on the anti-tumor activity by combinatorial inhibition of IDE397 and clinical stage PRMT5 inhibitors AMG 193 and BMS-986504 in MTAP-deleted tumors were included in a poster presentation. Reported positive interim data from 18 evaluable MTAP-deletion UC and NSCLC patients and selected the move-forward Phase 2 expansion dose (RP2D) in an Investor Webcast in July 2024. Enrollment is ongoing in the IDE397 and AMG 193 Phase 1 dose escalation, and targeting expansion in NSCLC in late 2024 to early 2025. Ongoing Phase 1 trial evaluating IDE397 in combination with Trodelvy in MTAP-deletion UC; targeting combination expansion in the fourth quarter of 2024. The PR reported at ENA 2024 has confirmed by RECIST 1.1. IDE161 in Tumors with Homologous Recombination Deficiency Targeting Phase 1/2 monotherapy expansion for IDE161 PARG inhibitor in priority solid tumor type(s) in the fourth quarter of 2024. Targeting first-patient-in for the Phase 1 trial evaluating IDE161, IDEAYA's first-in-class potential PARG inhibitor, in combination with Merck's (known as MSD outside of the US and Canada) anti-PD-1 therapy, KEYTRUDA® (pembrolizumab), in MSI-High and MSS endometrial cancer (EC) in the fourth quarter of 2024. Preclinical data on IDE161 and antibody drug conjugate (ADC) combination rationale presented as a poster at ENA 2024. Received FDA IND clearance for IDE275 (GSK959), a potential first-in-class and best-in-class Werner Helicase inhibitor, for a Phase 1 trial in high microsatellite instability (MSI-High) tumors and earned a $7.0 million milestone from GSK. Targeting Development Candidate nomination for MTAP-deletion, KAT6 pathway and B7H3/PTK7 Topo-Payload Bispecific-ADC programs in the fourth quarter of 2024. IDEAYA is targeting to host a Virtual Investor R&D Day on Monday, December 16, 2024, to highlight IDEAYA's potential first-in-class preclinical and clinical pipeline with management, leading Key Opinion Leader(s) (KOLs), and Pharma partner(s). Corporate Development Raised gross proceeds of approximately $302.4 million in July 2024 through public offering, generating net proceeds of approximately $283.8 million. Appointed Douglas B. Snyder as Senior Vice President, General Counsel. Mr. Snyder brings over 25 years of legal experience with leading healthcare organizations, including GW Pharmaceuticals, Actelion Pharmaceuticals, Eisai, GSK, and the U.S. FDA. Clinical Programs and Upcoming Milestones Darovasertib (IDE196) Program in Tumors with GNAQ or GNA11 Mutations Darovasertib is a potent and selective protein kinase C (PKC) inhibitor being developed to broadly address primary and metastatic UM. Darovasertib is currently being evaluated in four ongoing clinical trials. The darovasertib and crizotinib combination in MUM has FDA Fast Track designation: IDE196-002 (NCT05987332) is a Phase 2/3 potentially registration-enabling clinical trial of darovasertib + crizotinib in first-line human leukocyte antigens (HLA)-A2*02:01 negative (-) MUM. Over 150 patients enrolled as of October 31, 2024. IDE196-001 (NCT03947385) is a Phase 1/2 clinical trial of darovasertib + crizotinib in which we are planning to enroll additional HLA-A2*02:01 positive (+) patients. Phase 2 trials of darovasertib as neoadjuvant / adjuvant therapy in primary UM: IDE196-009 (NCT05907954) is a company-sponsored Phase 2 trial evaluating darovasertib as neoadjuvant treatment of UM prior to primary interventional treatment of enucleation or radiation therapy, and as adjuvant therapy following the primary treatment. Over 75 patients enrolled as of October 31, 2024. NADOM (NCT05187884) is a Phase 2 neoadjuvant / adjuvant trial of darovasertib in ocular melanoma. This is an IST led by Anthony Joshua, MBBS, PhD, FRACP, Head Department of Medical Oncology, Kinghorn Cancer Centre, St. Vincent's Hospital in Sydney with additional participating sites in Melbourne, Australia. Positive interim efficacy data from both the company-sponsored and the IST trials were highlighted during an Investor webcast in September 2024: 31 enucleation and 18 plaque brachytherapy evaluable UM patients treated with darovasertib neoadjuvant therapy in Phase 2 company-sponsored and IST trials. ~59% (29 of 49) of patients with >20% ocular tumor shrinkage by product of diameters. ~49% (24 of 49) of patients with >30% ocular tumor shrinkage by product of diameters. ~61% (19 of 31) eye preservation rate observed. Evidence of predicted visual preservation observed by reducing the amount of radiation associated with plaque brachytherapy. Manageable AE profile observed from Phase 2 company-sponsored trial (n=38), including 11% grade 3 or higher AEs, and 5% serious AE rate. The discontinuation rate observed was 3%. The most common AEs observed included diarrhea, nausea, vomiting and fatigue. IDEAYA had a successful Type C meeting with the FDA to discuss the clinical trial design for a registration-enabling Phase 3 trial in neoadjuvant UM patients. The planned trial aims to enroll approximately 400 patients in two cohorts: cohort 1 of plaque brachytherapy eligible UM patients, and cohort 2 of enucleation eligible UM patients. Cohort 1 will be randomized to darovasertib followed by plaque brachytherapy versus plaque brachytherapy alone, and cohort 2 will be randomized with or without darovasertib as neoadjuvant therapy. The primary endpoint of the trial is planned to be time to vision loss and eye preservation rate for cohort 1 and 2, respectively. The secondary endpoint for the trial is no detriment to Event-Free-Survival (EFS). Discussions with the FDA are ongoing regarding surrogate and composite endpoints to support earlier approval scenarios. IDEAYA is currently finalizing the trial protocol and is targeting to initiate the potential Phase 3 registration-enabling study in the first half of 2025. IDE397 Program in Tumors with MTAP Deletion IDE397 is a potent and selective small molecule inhibitor targeting methionine adenosyltransferase 2 alpha (MAT2A) in patients having solid tumors with methylthioadenosine phosphorylase (MTAP) deletion. IDEAYA continues to evaluate IDE397 in two trials in select monotherapy indications and in high conviction clinical combinations: IDE397-001 (NCT04794699) is a Phase 1/2 treatment study with a monotherapy expansion in MTAP-deletion UC and NSCLC. The estimated U.S. MTAP-deletion annual incidence in UC and NSCLC is approximately 48,000 patients. Encouraging clinical activity at the 30 mg once-a-day Phase 2 monotherapy expansion dose was observed in the Phase 1 clinical trial evaluating IDE397 in heavily pre-treated MTAP-deletion UC and NSCLC patients presented at ENA 2024 in October 2024. The patients evaluated had a median of two to three prior lines-of-therapy, ranging from one to seven. The reported Phase 1 clinical expansion data was based on 27 evaluable MTAP-deletion patients, including 10 UC, nine adenocarcinoma (Adeno) NSCLC, and eight squamous (Sq) NSCLC patients at the expansion dose of 30 mg once-a-day of IDE397 : ~33% Overall Response Rate (ORR). One complete response (CR) and eight partial responses (PRs) by RECIST 1.1 evaluation out of 27 evaluable patients. Nine of nine responses have been confirmed by RECIST 1.1, including four UC patients, of which one was a CR, three squamous NSCLC patients, and two adenocarcinoma NSCLC patients. Two patients confirmed after the data cutoff date. In the earlier reported July 8, 2024, IDE397 webcast program update, five confirmed responses were reported out of 18 evaluable MTAP-deletion UC and NSCLC patients by RECIST 1.1. There were zero non-evaluable patients reported as of the data analysis. Confirmed ORR% by RECIST 1.1 by Solid Tumor Type: MTAP-deletion UC = 40% (4 of 10) confirmed ORR%; MTAP-deletion squamous NSCLC = ~38% (3 of 8) confirmed ORR%; MTAP-deletion adenocarcinoma NSCLC = ~22% (2 of 9) confirmed ORR%. Multiple confirmed partial responses by RECIST 1.1 harbor genetic co-alterations, including MTAP-deletion and KRAS G12D mutation in NSCLC, and MTAP-deletion and FGFR-TACC3 fusion in UC. ~93% Disease Control Rate (DCR). One CR, eight PRs, and 16 stable disease (SD) by RECIST 1.1 evaluation out of 27 evaluable patients. Preliminary durability assessment: 15 of 27 patients still on treatment. Seven of nine RECIST 1.1 responses remain on treatment. Median duration of treatment (DOT) has not been reached and is greater than 6.2 months and median time to response (TTR) is ~2.7 months. The median duration of response and median progression free survival data is still immature. Three UC patients on treatment greater than 250 days, four squamous NSCLC patients on treatment greater than 200 days, and three adenocarcinoma NSCLC patients on treatment greater than 200 days ~81% circulating tumor DNA (ctDNA) Molecular Response Rate (MRR). 17 of 21 patients with 50% or greater ctDNA reduction, and ~33% (7 of 21) with deep 90% or greater ctDNA reduction. All MRs (17 of 17) were rapid occurring at the first ctDNA sample analysis. There were several quality control failures of patient samples that led to unavailability for MR analysis Favorable adverse event (AE) profile. Approximately 18% grade 3 or higher drug-related AEs and no drug-related serious adverse events (SAEs) observed at the IDE397 30mg once-a-day expansion dose. No drug-related AEs leading to discontinuations were observed. We anticipate that the favorable AE profile and dosing convenience of a 30 mg once-a-day tablet has the potential to enable long-term dosing and combination development, including with MTA-cooperative PRMT5 inhibitors and topoisomerase payload antibody drug conjugates (ADCs) Over 35 global clinical trial sites activated in the U.S., Canada, Europe and Asia Pasic to enable rapid enrollment. Targeting development of IDE397 registrational plan in MTAP-deletion solid tumors in 2025. Phase 1/2 trial of IDE397 and AMG 193 in MTAP-Deletion NSCLC (Amgen-sponsored study, NCT05975073) Preclinical poster presentation on the antitumor activity by combinatorial inhibition of MAT2A and PRMT5 in MTAP-deleted tumors presented at ENA 2024. Enrollment is ongoing in the IDE397 and AMG193 Phase 1 dose escalation. Targeting expansion in NSCLC in late 2024 to early 2025. Phase 1 trial of IDE397 and Trodelvy in MTAP-deletion UC (IDEAYA-sponsored, NCT04794699) evaluating the safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy is ongoing. Reported the first preliminary clinical case study of the IDE397 and Trodelvy combination in MTAP-deletion UC at ENA 2024, including a PR by RECIST 1.1 in a patient case report with a genetic co-alteration of MTAP-deletion and a FGFR3-TACC3 fusion, and rapid and deep first-evaluation molecular responses with ctDNA reduction of greater than 95% observed. The PR reported at ENA 2024 has now confirmed by RECIST 1.1. Targeting to initiate the IDE397 and Trodelvy Phase 1/2 combination expansion in MTAP-deletion UC in Q4 2024. Pursuant to the clinical study collaboration and supply agreement, IDEAYA and Gilead retain the commercial rights to their respective compounds, including with respect to use as a monotherapy or combination agent. IDEAYA is the study sponsor and Gilead will provide the supply of Trodelvy to IDEAYA. IDE397 monotherapy or in combination with Trodelvy has not been approved by any regulatory agency and the efficacy and safety of this combination has not been established. IDE161 Program in Tumors with Homologous Recombination Deficiency IDE161 is a potential first-in-class inhibitor of poly(ADP-ribose) glycohydrolase (PARG), a novel, mechanistically distinct target in the same clinically validated biological pathway as poly(ADP-ribose) polymerase (PARP). IDE161 received two FDA Fast Track designations in platinum-resistant advanced or metastatic ovarian cancer patients having tumors with BRCA1/2 mutations, and in pretreated advanced or metastatic HR+, Her2-, BRACA1/2 mutant breast cancer. IDE161 is currently being evaluated in IDE161-001 (NCT05787587), a Phase 1 trial of IDE161 monotherapy in solid tumors with homologous recombination deficiency (HRD) and in the planned combination with Merck's anti-PD-1 therapy, KEYTRUDA® (pembrolizumab) in microsatellite instability high (MSI-High) and microsatellite stable (MSS) endometrial cancer. Selection of an initial Phase 1/2 IDE161 monotherapy expansion dose in priority solid tumors type(s) is targeted in the fourth quarter of 2024. Separately, a first-patient-in for IDE161 in combination with KEYTRUDA is targeted in the fourth quarter of 2024. KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA. In addition, preclinical results on IDE161 and ADC combination rationale were presented as a poster at ENA 2024. GSK-Partnered Programs IDE705 (GSK101) Program in Tumors with HRD IDE705 (GSK101) is a potential first-in-class small molecule inhibitor of Pol Theta Helicase being developed as a combination treatment with niraparib for advanced solid tumors with HRD. The dose escalation portion of the GSK-sponsored Phase 1/2 clinical trial to evaluate GSK101 in combination with niraparib, the GSK small molecule inhibitor of PARP, for patients having solid tumors with BRCA or other HR mutations, or with HRD is currently ongoing. Upon initiation of the Phase 1 dose expansion, IDEAYA will be eligible to receive a $10.0 million milestone payment, with the collaboration having potential further aggregate later-stage development and regulatory milestones of up to $465.0 million. GSK is responsible for all research and development costs for the program. Upon commercialization, IDEAYA will be eligible to receive up to $475 million of commercial milestones, and tiered royalties on global net sales of GSK101 – ranging from high single-digit to sub-teen double-digit percentages, subject to certain customary reductions. IDE275 (GSK959) Program in Tumors with MSI-High IDE275 (GSK959) is a potential first-in-class Werner helicase inhibitor that received FDA IND clearance for a Phase 1 trial in October 2024. The GSK-sponsored Phase 1 trial will evaluate IDE275 (GSK959) in patients having MSI-High tumors, as a monotherapy and in combination with a PD-1 inhibitor. IDEAYA earned a $7 million milestone payment for the IND clearance and has the potential to earn up to an additional $10.0 million upon initiation of Phase 1 clinical dose expansion. In addition, IDEAYA is entitled to receive up to $465.0 million in further later-stage development and regulatory milestones. GSK is responsible for 80% of global research and development costs and IDEAYA is responsible for 20% of such costs. Upon commercialization, IDEAYA will be eligible to receive up to $475 million of commercial milestones, 50% of U.S. net profits and tiered royalties on global non-U.S. net sales of the Werner Helicase inhibitor development candidate (DC) – ranging from high single-digit to sub-teen double-digit percentages, subject to certain customary reductions. B7H3/PTK7 Topo-Payload BsADC Program IDEAYA entered into an option and license agreement for a potential first-in-class B7H3/PTK7 Topo-Payload BsADC program with Biocytogen in July 2024. The agreement grants IDEAYA an option for an exclusive worldwide license from Biocytogen for a potential first-in-class B7H3/PTK7 Topo-Payload BsADC program. B7H3/PTK7 has been found to be co-expressed in multiple solid tumor types, including double-digit percent prevalence in lung, colorectal, and head and neck cancers, among others. Based on preclinical data, the potential first-in-class B7H3/PTK7 Topo-Payload BsADC program has the potential to be developed as a monotherapy agent and used in combination with multiple programs in IDEAYA's pipeline targeting DDR-based therapies, including the PARG inhibitor IDE161. A development candidate nomination for the B7H3/PTK7 Topo-Payload BsADC program is targeted in the fourth quarter of 2024. Next-Generation Precision Medicine Pipeline Programs Early preclinical research programs focused on pharmacological inhibition of several new targets for patients with solid tumors characterized by defined biomarkers based on genetic mutations and/or molecular signatures are ongoing. These programs have the potential for discovery and development of first-in-class or best-in-class therapeutics with multiple wholly owned DC nominations targeted in the fourth quarter of 2024, including in MTAP-deletion solid tumors indications to enable a potential wholly-owned clinical combination with IDE397, and separately a DC nomination in the lysine acetyltransferase 6 (KAT6) pathway. Financial Results As of September 30, 2024, IDEAYA had cash, cash equivalents and marketable securities totaling $1.2 billion. This compared to cash, cash equivalents and marketable securities of $952.7 million as of June 30, 2024. The increase was primarily attributable to $283.8 million in net proceeds from the underwritten public offering of common stock and pre-funded warrants to purchase common stock in July 2024, partially offset by net cash used in operations. Research and development (R&D) expenses for the three months ended September 30, 2024 totaled $57.2 million compared to $54.5 million for the three months ended June 30, 2024. The increase was primarily due to clinical trial and outside services expenses. General and administrative (G&A) expenses for the three months ended September 30, 2024 totaled $9.7 million compared to $10.4 million for the three months ended June 30, 2024. The decrease was primarily due to stock-based compensation expense. The net loss for the three months ended September 30, 2024 was $51.8 million compared to the net loss of $52.8 million for the three months ended June 30, 2024. Total stock compensation expense for the three months ended September 30, 2024 was $9.2 million compared to $9.7 million for the three months ended June 30, 2024. About IDEAYA Biosciences IDEAYA is a precision medicine oncology company committed to the discovery and development of targeted therapeutics for patient populations selected using molecular diagnostics. IDEAYA's approach integrates capabilities in identifying and validating translational biomarkers with drug discovery to select patient populations most likely to benefit from its targeted therapies. IDEAYA is applying its research and drug discovery capabilities to synthetic lethality – which represents an emerging class of precision medicine targets. IDEAYA's updated corporate presentation is available on its website, at its Investor Relations page: . Forward-Looking Statements This press release contains forward-looking statements, including, but not limited to, statements related to (i) the timing, content and venue of clinical program updates, (ii) the timing of expansion of Phase 1/2 trial of IDE397 in combination with Trodelvy® in MTAP-deletion UC, (iii) the timing of expansion of Phase 1 trial of IDE397 in combination with AMG 193 in NSCLC, (iv) the timing of finalization of Phase 3 registration trial protocol and initiation of trial for darovasertib, (v) the timing of a first-patient-in in the IDE161 and KEYTRUDA combination study, (vi) the timing of DC nominations for MTAP-deletion, KAT6 pathway and B7H3/PTK7 Topo-Payload Bispecific-ADC programs, (vii) the timing of designation of next generation development candidates, (viii) the extent to which IDEAYA's existing cash, cash equivalents, and marketable securities will fund its planned operations, (ix) the estimate of patient populations, (x) additional clinical combinations, and (xi) the receipt of development and regulatory milestones. 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 20, 2024 and any current and periodic reports filed with the U.S. Securities and Exchange Commission. Investor and Media Contact IDEAYA Biosciences Andres Ruiz Briseno SVP, Head of Finance and Investor Relations [email protected] SOURCE IDEAYA Biosciences, Inc. WANT YOUR COMPANY'S NEWS FEATURED ON PRNEWSWIRE.COM? 440k+ Newsrooms & Influencers 9k+ Digital Media Outlets 270k+ Journalists Opted In GET STARTED

Darovasertib achieves triple-digit enrollment in Phase 2/3 trial in 1L HLA-A2*02:01(-) MUM; and >50 patients enrolled in Phase 2 neoadjuvant UM study ASCO 2024 oral presentation of darovasertib in neoadjuvant UM; FDA Type C meeting for neoadjuvant UM in Q3'24 and targeting Phase 2 neoadjuvant UM data update in H2'24 Demonstrated preliminary proof-of-concept for IDE397 in MTAP urothelial and lung cancer; 1 PR awaiting confirmation has confirmed and 1 additional PR still awaiting confirmation, from the 2 uPRs noted in the July 8, 2024 webcast IDEAYA, in consultation with Amgen, has now financially budgeted to support its obligations for target IDE397 / AMG 193 clinical combination expansion in NSCLC Phase 1 FPI achieved for IDE397 and Trodelvy® combo in MTAP-deletion urothelial cancer Targeting initial IDE161 Ph 1/2 expansion and Phase 1 FPI for IDE161 in combination with Merck's anti-PD-1 therapy KEYTRUDA® (pembrolizumab) in endometrial cancer in H2'24 Targeting Werner IND in H2'24, and MTAP and KAT6 pathway DCs in H2'24 Targeting B7H3/PTK7 Topo-Payload Bispecific-ADC DC nomination in H2'24 IDEAYA to host an Investor R&D Day in Q4 2024 $952.7 million of cash, cash equivalents and marketable securities as of June 30, 2024, supplemented by net proceeds of $283.8 million from July 2024 public offering, anticipated to fund operations into at least 2028 SOUTH SAN FRANCISCO, Calif., Aug. 6, 2024 /PRNewswire/ -- IDEAYA Biosciences, Inc. (Nasdaq: IDYA), a precision medicine oncology company committed to the discovery and development of targeted therapeutics, provided a business update, and announced financial results for the second quarter ended June 30, 2024. "We made significant progress advancing four potential first-in-class precision medicine oncology clinical programs this past quarter, and we are on-track to deliver our fifth potential first-in-class program to the clinic this year in Werner Helicase. Importantly, we presented preliminary clinical proof of concept data for IDE397 monotherapy in MTAP-deletion urothelial and lung cancer, demonstrating the ability to deliver confirmed RECIST responses with a favorable AE profile. The IDE397 combination therapy trials in MTAP-deletion solid tumors with our collaborators continue to progress, with the first patient dosed in the Phase 1 trial evaluating IDE397 with Gilead's Trodelvy, and continued dose escalation in the AMG 193 clinical combination with Amgen. We look forward to hosting an investor R&D Day that will profile our rapidly advancing potential first-in-class precision medicine oncology pipeline, where we are targeting multiple additional development candidates by the end of this year," said Yujiro S. Hata, President and Chief Executive Officer, IDEAYA Biosciences. "We were excited to share the compelling interim clinical data from the investigator- and company-sponsored Phase 2 trials of darovasertib in neoadjuvant UM, and look forward to discussing the registrational path forward with the FDA and providing our company-sponsored Phase 2 trial update in over 30 patients during the second half of this year. In addition, the most recent positive interim results observed with IDE397 monotherapy, in addition to the ongoing combination trials, bring us closer to potentially addressing a high unmet need in MTAP-deletion NSCLC, urothelial cancer and other solid tumors, and we are targeting developing a registrational plan in 2025. Separately, we anticipate initiating both the Phase 2 IDE161 monotherapy expansion cohort and the IDE161 in combination with KEYTRUDA cohort in the second half of 2024," said Darrin Beaupre, M.D., Ph.D., Chief Medical Officer, IDEAYA Biosciences. Summary of Q2 and Recent Key Developments Research and Clinical Development Darovasertib in neoadjuvant uveal melanoma (UM) Interim data from the investigator-sponsored Phase 2 trial were presented at the American Society of Clinical Oncology (ASCO) 2024 meeting by Anthony Joshua, MBBS, PhD, FRACP, Head Department of Medical Oncology, Kinghorn Cancer Centre, St. Vincent's Hospital in Sydney, and the lead principal investigator of the study. The company-sponsored Phase 2 trial has enrolled over 50 patients in 20 sites globally as of July 31, 2024; a clinical update from eight patients was provided. An additional clinical data update in over 30 patients is planned in the second half of 2024. IDEAYA has scheduled a Type C meeting with the U.S. Food and Drug Administration (FDA) to discuss a potential registrational trial for darovasertib in the neoadjuvant UM setting in the third quarter of 2024. IDE397 in MTAP-Deletion Solid Tumors Selected 30 mg as move-forward Phase 2 expansion dose in MTAP-deletion urothelial cancer and squamous non-small cell lung cancer (NSCLC). Reported positive interim data from 18 evaluable urothelial cancer and NSCLC patients. Announced first-patient-in (FPI) for Phase 1 trial evaluating IDE397 in combination with Gilead's Trodelvy in MTAP-deletion urothelial cancer. The IDE397 / AMG 193 clinical combination dose escalation is ongoing. In the past quarter, IDEAYA, in consultation with Amgen, has now financially budgeted to support its obligations for target IDE397 / AMG 193 clinical combination expansion in NSCLC. Entered into an option and license agreement for a potential first-in-class B7H3/PTK7 topo-I-payload bispecific antibody drug conjugate (B7H3/PTK7 Topo-Payload BsADC) program with Biocytogen Pharmaceuticals (Beijing) Co., Ltd. (Biocytogen) in July 2024. A development candidate nomination is targeted for the second half of 2024. IDEAYA plans to host an Investor R&D Day in Q4 2024. Corporate Development Raised gross proceeds of approximately $302.4 million in July 2024 through public offering, generating net proceeds of approximately $283.8 million. Appointed Daniel A. Simon as Chief Business officer. Mr. Simon brings over 18 years of experience at leading life science and strategy consulting companies. Clinical Programs and Upcoming Milestones Darovasertib (IDE196) Program in Tumors with GNAQ or GNA11 Mutations Darovasertib is a potent and selective protein kinase C (PKC) inhibitor being developed to broadly address primary and metastatic UM. Darovasertib is currently being evaluated in four ongoing clinical trials. The darovasertib and crizotinib combination in MUM has FDA Fast Track designation: IDE196-002 (NCT05987332) is a Phase 2/3 potentially registration-enabling clinical trial of darovasertib + crizotinib in first-line human leukocyte antigens HLA-A2*02:01(-) MUM. Triple digit patient enrollment has been achieved as of July 31, 2024. IDE196-001 (NCT03947385) is a Phase 1/2 clinical trial evaluating darovasertib + crizotinib in GNAQ/11 melanomas, including in MUM and metastatic cutaneous melanoma. Phase 2 trials of darovasertib as neoadjuvant / adjuvant therapy in primary UM: IDE196-009 (NCT05907954) is a company-sponsored Phase 2 trial evaluating darovasertib as neoadjuvant treatment of UM prior to primary interventional treatment of enucleation or radiation therapy, and as adjuvant therapy following the primary treatment. Interim efficacy and safety results were reported in conjunction with the Phase 2 investigator-initiated trial (IST) interim data ASCO 2024 presentation. Data from eight patients (six enucleation and two plaque eligible) who have been on darovasertib treatment for 4 months or more as of the database lock of May 24, 2024 demonstrated a median tumor shrinkage (maximum height/base/volume change) of approximately 40%/25%/72% and the majority of the six enucleation patients had reported Eye Saved (i.e., converted to plaque brachytherapy or external beam radiotherapy (EBRT) eligible). Darovasertib had a manageable adverse events (AEs) profile with no drug-related serious adverse events (SAEs) observed; drug-related AEs were predominantly Grade 1 or Grade 2 and approximately 13% of patients reported at least one drug-related Grade 3 AE. The trial has enrolled over 50 patients in 20 sites globally, as of July 31, 2024. An amendment to the study protocol was submitted to the FDA in July 2024 to enable dosing of darovasertib as neoadjuvant and adjuvant therapy up to 12 months each. As part of this amendment the number of patients in the study was increased from 82 to 122 patients and the part 2 of the study will, once the amendment is effective, consist of adjuvant treatment with darovasertib in combination with crizotinib for patients with disease characteristics suggesting high or intermediate risk of metastasis. Additional clinical efficacy update from the company-sponsored Phase 2 of darovasertib neoadjuvant UM trial in over 30 patients is anticipated in the second half of 2024. NADOM (NCT05187884) is a Phase 2 neoadjuvant / adjuvant trial of darovasertib in ocular melanoma. This is an IST led by Anthony Joshua, MBBS, PhD, FRACP, Head Department of Medical Oncology, Kinghorn Cancer Centre, St. Vincent's Hospital in Sydney with additional participating sites in Melbourne, Australia. Interim efficacy and safety results were presented at the ASCO 2024 meeting. As of the database lock on May 14, 2024, 13 patients had completed neoadjuvant treatment, 11 patients received adjuvant darovasertib after primary treatment of their UM, with five patients completing the planned six months of therapy. At that time, 75% (nine out of 12 enucleation patients) had confirmed Eye Saved (i.e., converted to plaque brachytherapy or EBRT). After six months, approximately 67% (eight out of 12 enucleation patients) observed greater than 30% tumor shrinkage (maximum volume change) and median tumor shrinkage (maximum volume change) was approximately 47%. Darovasertib monotherapy neoadjuvant treatment had a manageable AE profile with no drug-related SAEs observed. Drug-related AEs were predominantly Grade 1 or Grade 2 and 20% of patients reported at least one drug-related Grade 3 AE. IDEAYA has scheduled a Type C meeting with the FDA in the third quarter of 2024 to discuss a potential registrational trial for darovasertib in the neoadjuvant UM setting. IDE397 Program in Tumors with MTAP Deletion IDE397 is a potent and selective small molecule inhibitor targeting methionine adenosyltransferase 2 alpha (MAT2A) in patients having solid tumors with methylthioadenosine phosphorylase (MTAP) deletion. IDEAYA continues to focus on evaluating IDE397 in two trials in select monotherapy indications and in high conviction clinical combinations: IDE397-001 (NCT04794699) is a Phase 1/2 treatment study with monotherapy expansion in MTAP-deletion NSCLC and urothelial cancer. The estimated U.S. MTAP-deletion annual incidence in NSCLC and urothelial cancer is approximately 48,000 patients. Selected 30 mg as the move-forward expansion dose for IDE397 monotherapy in MTAP-deletion urothelial cancer and squamous NSCLC based on adverse event profile and preliminary clinical efficacy observed. Over 35 global clinical trial sites activated to enable rapid enrollment. Reported positive interim data from 18 evaluable MTAP-deletion urothelial and NSCLC patients by RECIST 1.1: ~39% Overall Response Rate (ORR) observed with one complete response and six partial responses. Two partial responses were awaiting confirmation at the time of the update (July 8, 2024), and one urothelial cancer patient that had a 100% tumor reduction in the target lesion at the last CT-scan assessment has now been confirmed. The second adenocarcinoma NSCLC patient is still awaiting confirmation as of July 31, 2024 In patients with urothelial cancer: One complete response and two partial responses were observed. In patients with lung cancer: three partial responses were seen in squamous NSCLC patients, and one partial response seen in adenocarcinoma NSCLC patient. There was one non-evaluable patient who discontinued due to rapid clinical progression of cancer fatigue and drug-unrelated adverse events in cycle 1 of treatment. ~94% Disease Control Rate (DCR) seen with one complete response, six partial responses, and 10 stable disease. ~78% of patients (14/18) experienced tumor shrinkage. Preliminary durability assessment showed 11 of the 18 patients are still on treatment, and five of seven RECIST 1.1 responses remain in response. Median duration of treatment, median duration of response, and median progression free survival not yet reached. ~81% circulating tumor DNA (ctDNA) Molecular Response (MR) Rate observed in evaluable subjects with 13 of 16 patients with 50% or greater ctDNA reduction. There were several quality control failures of patient samples that led to unavailability for MR analysis. Overall favorable AE profile. Approximately 5.6% grade 3 or higher drug-related AEs and no drug-related SAEs reported at IDE397 30 mg once-a-day expansion dose. No drug-related AEs leading to discontinuations observed. We anticipate that the favorable AE profile and dosing convenience of a 30 mg once-a-day tablet has the potential to enable long-term dosing and combination development. 30 mg once daily expansion dose achieves target drug coverage and plasma S-adenosyl-l-methionine (SAM) pharmacodynamic reduction associated with preclinical tumor regressions. Targeting development of IDE397 registrational plan in MTAP-deletion solid tumors in 2025. Phase 1/2 trial of IDE397 and AMG 193 in MTAP-Deletion NSCLC (Amgen-sponsored study, NCT05975073) Targeting development of joint publication strategy on IDE397 and AMG193 combination in 2024. At this time, the IDE397 / AMG 193 clinical combination dose escalation is ongoing. In the past quarter, IDEAYA, in consultation with Amgen, has now financially budgeted to support its obligations for target IDE397 / AMG 193 clinical combination expansion in NSCLC. First patient dosed in the Phase 1 trial of IDE397 and Trodelvy in MTAP-deletion urothelial cancer (IDEAYA-sponsored, NCT04794699) evaluating the safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy. The MAT2A-Trop2 antibody-drug conjugate (ADC) combination targets two distinct, yet complementary nodes in the 26% of patients with MTAP-deleted urothelial cancer and has first-in-class potential to improve clinical outcomes for urothelial cancer patients. IDE161 Program in Tumors with Homologous Recombination Deficiency IDE161 is a potential first-in-class inhibitor of poly(ADP-ribose) glycohydrolase (PARG), a novel, mechanistically distinct target in the same clinically validated biological pathway as poly(ADP-ribose) polymerase (PARP). IDE161 received two FDA Fast Track designations in platinum-resistant advanced or metastatic ovarian cancer patients having tumors with BRCA1/2 mutations, and in pretreated advanced or metastatic HR+, Her2-, BRACA1/2 mutant breast cancer. IDE161 is currently being evaluated as a monotherapy in IDE161-001 (NCT05787587), a Phase 1 trial of IDE161 in solid tumors with homologous recombination deficiency (HRD). Selection of an initial Phase 1/2 monotherapy expansion dose in HRD solid tumors remains on track for the second half of 2024. IDEAYA is currently validating IDE161 combination opportunities preclinically and targeting identification of additional combination(s) in 2024. Additionally, IDEAYA is planning to evaluate IDE161 in combination with KEYTRUDA® in patients with microsatellite instability (MSI)-high and microsatellite stable (MSS) endometrial cancer. Clinical first-patient-in for the IDE161 and KEYTRUDA® combination is targeted in the second half of 2024. KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA. GSK-Partnered Programs GSK101 (IDE705) Program in Tumors with HRD GSK101 (IDE705) is a potential first-in-class small molecule inhibitor of Pol Theta Helicase being developed as a combination treatment with niraparib for advanced solid tumors with HRD. The dose escalation portion of the GSK-sponsored Phase 1/2 clinical trial to evaluate GSK101 in combination with niraparib, the GSK small molecule inhibitor of PARP, for patients having solid tumors with BRCA or other HR mutations, or with HRD is currently ongoing. Upon initiation of the Phase 1 dose expansion, IDEAYA will be eligible to receive a $10.0 million milestone payment, with the collaboration having a potential further aggregate later-stage development and regulatory milestones of up to $465.0 million. GSK is responsible for all research and development costs for the program. Upon commercialization, IDEAYA will be eligible to receive up to $475 million of commercial milestones, and tiered royalties on global net sales of GSK101 – ranging from high single-digit to sub-teen double-digit percentages, subject to certain customary reductions. Werner Helicase Inhibitor in Tumors with High MSI IDEAYA and GSK remain on track for an IND filing in the second half of 2024 for the selected Werner Helicase inhibitor announced in December 2023. The IND-enabling Good Laboratory Practice (GLP) toxicology studies have been completed for the Werner Helicase inhibitor development candidate. IDEAYA has the potential to earn up to an additional $17.0 million in aggregate milestones through early Phase 1, including $7.0 million upon IND clearance, and is entitled to receive up to $465.0 million in further later-stage development and regulatory milestones. GSK is responsible for 80% of global research and development costs and IDEAYA is responsible for 20% of such costs. Upon commercialization, IDEAYA will be eligible to receive up to $475 million of commercial milestones, 50% of U.S. net profits and tiered royalties on global non-U.S. net sales of the Werner Helicase inhibitor development candidate (DC) – ranging from high single-digit to sub-teen double-digit percentages, subject to certain customary reductions. B7H3/PTK7 Topo-Payload BsADC Program IDEAYA entered into an option and license agreement for a potential first-in-class B7H3/PTK7 Topo-Payload BsADC program with Biocytogen in July 2024. The agreement grants IDEAYA an option for an exclusive worldwide license from Biocytogen for a potential first-in-class B7H3/PTK7 Topo-Payload BsADC program. B7H3/PTK7 has been found to be co-expressed in multiple solid tumor types, including double-digit percent prevalence in lung, colorectal, and head and neck cancers, among others. Based on preclinical data, the potential first-in-class B7H3/PTK7 Topo-Payload BsADC program has the potential to be developed as a monotherapy agent and used in combination with multiple programs in IDEAYA's pipeline targeting DDR-based therapies, including PARG inhibitor IDE161. A development candidate nomination for the B7H3/PTK7 Topo-Payload BsADC program is targeted for the second half of 2024. Under the terms of the agreement, Biocytogen will receive an upfront fee and, upon an option exercise by IDEAYA, be entitled to receive an option exercise fee, development and regulatory milestones and commercial milestone payments, as well as single-digit royalties on net sales. Total potential upfront, option exercise and milestone payments equal an aggregate of $406.5 million, including development and regulatory milestones of $100.0 million. Next-Generation Precision Medicine Pipeline Programs Early preclinical research programs focused on pharmacological inhibition of several new targets for patients with solid tumors characterized by defined biomarkers based on genetic mutations and/or molecular signatures are ongoing. These programs have the potential for discovery and development of first-in-class or best-in-class therapeutics with multiple wholly owned DC nominations targeted in the second half of 2024, including in MTAP-deletion solid tumors indications to enable a potential wholly-owned clinical combination with IDE397 and the lysine acetyltransferase 6 (KAT6) pathway. Financial Results As of June 30, 2024, IDEAYA had cash, cash equivalents and marketable securities totaling $952.7 million. This compared to cash, cash equivalents and marketable securities of $941.4 million as of March 31, 2024. The increase was primarily attributable to net proceeds of $36.5 million from the sale of common stock shares through IDEAYA's at-the-market offering program during the period from April 1, 2024 to June 30, 2024, partially offset by net cash used in operations. Subsequent to the reporting period for the quarter ended June 30, 2024, IDEAYA announced the closing in July 2024 of an underwritten public offering of common stock and pre-funded warrants to purchase common stock, generating net proceeds of approximately $283.8 million, after deducting the underwriting discounts and commissions and estimated offering expenses payable by IDEAYA. There was no collaboration revenue recognized for the three months ended June 30, 2024 similar to the three months ended March 31, 2024. We completed all performance obligations related to the upfront payment under the GSK collaboration agreement as of December 31, 2023. Future collaboration revenue recognized under the GSK collaboration agreement will be related to future milestone payments as they are earned. Research and development (R&D) expenses for the three months ended June 30, 2024 totaled $54.5 million compared to $42.8 million for the three months ended March 31, 2024. The increase was primarily due to higher stock-based compensation expenses, clinical trial expenses, professional and outside services and consulting expenses. General and administrative (G&A) expenses for the three months ended June 30, 2024 totaled $10.4 million compared to $8.2 million for the three months ended March 31, 2024. The increase was primarily due to higher stock-based compensation expenses, audit fees and consulting expenses. The net loss for the three months ended June 30, 2024 was $52.8 million compared to the net loss of $39.6 million for the three months ended March 31, 2024. Total stock compensation expense for the three months ended June 30, 2024 was $9.7 million compared to $6.3 million for the three months ended March 31, 2024. About IDEAYA Biosciences IDEAYA is a precision medicine oncology company committed to the discovery and development of targeted therapeutics for patient populations selected using molecular diagnostics. IDEAYA's approach integrates capabilities in identifying and validating translational biomarkers with drug discovery to select patient populations most likely to benefit from its targeted therapies. IDEAYA is applying its research and drug discovery capabilities to synthetic lethality – which represents an emerging class of precision medicine targets. IDEAYA's updated corporate presentation is available on its website, at its Investor Relations page: . Forward-Looking Statements This press release contains forward-looking statements, including, but not limited to, statements related to (i) the timing, content and venue of clinical program updates, (ii) the timing for the development of a joint Amgen/IDEAYA publication strategy, (iii) the timing of an FDA Type C meeting for neoadjuvant UM, (iv) the timing of initial Phase 1/2 monotherapy expansion for IDE161 in HRD solid tumors, (v) the timing of a first-patient-in in the IDE161 and KEYTRUDA combination study, (vi) the timing of IND submission for the Werner Helicase inhibitor DC, (vii) the timing of designation of next generation development candidates, (viii) the extent to which IDEAYA's existing cash, cash equivalents, and marketable securities will fund its planned operations, (ix) the estimate of patient populations, (x) additional clinical combinations, and (xi) the receipt of development and regulatory milestones. 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 20, 2024 and any current and periodic reports filed with the U.S. Securities and Exchange Commission. Investor and Media Contact IDEAYA Biosciences Andres Ruiz Briseno SVP, Head of Finance and Investor Relations [email protected] SOURCE IDEAYA Biosciences, Inc.

ASCO 2024 oral presentation of darovasertib neoadjuvant UM Phase 2 investigator-sponsored trial on June 3rd, and targeting neoadjuvant UM update in over 30 patients from Phase 2 company-sponsored trial and regulatory guidance both in H2 2024 Selected move-forward Phase 2 dose for IDE397 in MTAP squamous NSCLC, based on clinical efficacy observed in this indication, including multiple PRs by RECIST 1.1; and multiple PRs by RECIST 1.1 have also been observed in MTAP bladder cancer Enrollment is ongoing in the IDE397 and AMG 193 Phase 1 dose escalation and targeting development of joint Amgen / IDEAYA publication strategy in 2024 First-patient-in (FPI) for Phase 1 trial of IDE397 in combination with Gilead's Trodelvy® in MTAP bladder cancer targeted mid-year 2024 Targeting initial Phase 2 expansion for IDE161 in HRD solid tumors and Phase 1 FPI for IDE161 in combination with Merck's anti-PD-1 therapy KEYTRUDA® (pembrolizumab) in endometrial cancer both in H2 2024 IND-enabling GLP toxicology studies completed and targeting Werner IND-filing with GSK in H2 2024, representing 5th potential first-in-class clinical program; and targeting MTAP development candidate in H2 2024 to enable wholly-owned IDE397 combination Strong balance sheet of $941.4 million of cash, cash equivalents and marketable securities as of March 31, 2024, anticipated to fund operations into 2028 SOUTH SAN FRANCISCO, Calif., May 7, 2024 /PRNewswire/ -- IDEAYA Biosciences, Inc. (Nasdaq: IDYA), a precision medicine oncology company committed to the discovery and development of targeted therapeutics, provided a business update, and announced financial results for the first quarter ended March 31, 2024. "This quarter we continued to execute on our strategic vision to build a leading precision medicine oncology company, with the broad advancement of 4 potential first-in-class clinical programs across multiple patient selection biomarker populations, including GNAQ/11, MTAP-deletion, and HRD solid tumors. Next, through our excellence in translational research, we have discovered and enabled what we believe are potential first-in-class rational combinations across our diverse clinical pipeline, including with Pfizer, Amgen, Gilead, GSK, and Merck. IDEAYA's next generation programs have also made tremendous progress this past quarter, including the Werner Helicase program that is on-track for an IND-filing this year and our second MTAP-deletion program where we anticipate a development candidate in 2024 to enable a potential wholly-owned clinical combination with IDE397," said Yujiro S. Hata, President and Chief Executive Officer, IDEAYA Biosciences. "We are excited to provide a clinical data update from the ongoing investigator-sponsored Phase 2 neoadjuvant uveal melanoma trial as an oral presentation at ASCO 2024. In addition, we are targeting to provide a clinical data update from our company-sponsored Phase 2 neoadjuvant UM trial and receive FDA regulatory guidance for a potential registrational path in the neoadjuvant uveal melanoma indication in the second half of 2024. In addition, our potential first-in-class clinical pipeline including programs in Phase 1/2 such as the MAT2A inhibitor IDE397 which targets MTAP-deleted solid tumors and PARG inhibitor IDE161 which targets HRD solid tumors, both continue to make important advancements. For IDE397, we have selected a move-forward Phase 2 monotherapy expansion dose in MTAP-deletion squamous non-small cell lung cancer. For the IDE161 program, we are targeting to initiate the Phase 2 monotherapy expansion in HRD solid tumors in the second half of 2024," added Darrin Beaupre, M.D., Ph.D., Chief Medical Officer, IDEAYA Biosciences. Summary of Recent Key Developments Interim data from the investigator-sponsored Phase 2 trial of darovasertib in neoadjuvant UM accepted for an oral presentation at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting. Selected move-forward Phase 2 expansion dose for IDE397 monotherapy in MTAP-deletion squamous NSCLC, based on adverse event profile and preliminary clinical efficacy observed, including multiple partial responses in squamous NSCLC by RECIST 1.1. In addition, multiple partial responses by RECIST 1.1 have also been observed in MTAP-deletion bladder cancer with IDE397 monotherapy and evaluation is ongoing for further potential Phase 2 expansion in this tumor type. Enrollment is ongoing in the IDE397 and AMG 193 combination Phase 1 dose escalation. IDE161 Phase 1/2 dose escalation is ongoing and targeting initial Phase 2 expansion in HRD solid tumors in H2 2024. Established clinical trial collaboration with MSD International Business GmbH, a subsidiary of Merck & Co., Inc. Rahway, NJ, USA, in March 2024 to evaluate IDE161 in combination with KEYTRUDA in endometrial cancer with a first patient dosing targeted in the second half of 2024. IND-enabling GLP toxicology studies have been completed for the Werner Helicase inhibitor development candidate, in collaboration with GSK, representing IDEAYA's 5th potential first-in-class clinical program. Multiple development candidates targeted in H2 2024, including in MTAP-deletion to enable potential IDE397 clinical combination. Clinical Programs Update and Upcoming Milestones Darovasertib (IDE196) Program in Tumors with GNAQ or GNA11 Mutations Darovasertib is a potent and selective protein kinase C (PKC) inhibitor being developed to broadly address primary and metastatic UM. Darovasertib is currently being evaluated in four ongoing clinical trials, three of which are in collaboration with Pfizer. The darovasertib + crizotinib combination in MUM has U.S. Food & Drug Administration (FDA) Fast Track designation: IDE196-002 (NCT05987332) is a Phase 2/3 potentially registration-enabling clinical trial of darovasertib + crizotinib in first-line HLA-A2*02:01(-) MUM. Clinical program update(s) are anticipated in 2024. IDE196-001 (NCT03947385) is a Phase 1/2 clinical trial evaluating darovasertib + crizotinib in GNAQ/11 melanomas, including in MUM and metastatic cutaneous melanoma. Phase 2 trials of darovasertib as neoadjuvant / adjuvant therapy in primary UM: IDE196-009 (NCT05907954) is a company-sponsored Phase 2 trial evaluating darovasertib as neoadjuvant treatment of UM prior to primary interventional treatment of enucleation or radiation therapy, and as adjuvant therapy following the primary treatment. A clinical efficacy update on over 30 patients and an FDA regulatory guidance update are both targeted in the second half of 2024. NADOM (NCT05187884) is a Phase 2 neoadjuvant / adjuvant trial of darovasertib in ocular melanoma. This is an investigator-sponsored trial (IST) led by Anthony Joshua, MBBS, PhD, FRACP, Head Department of Medical Oncology, Kinghorn Cancer Centre, St. Vincent's Hospital in Sydney with additional participating sites in Melbourne, Australia. The interim results from the trial have been accepted for an oral presentation at the upcoming 2024 ASCO annual meeting on June 3, 2024. IDE397 Program in Solid Tumors and Bladder Cancer with MTAP Deletion IDE397 is a potent and selective small molecule inhibitor targeting methionine adenosyltransferase 2 alpha (MAT2A) in patients having solid tumors with methylthioadenosine phosphorylase (MTAP) deletion. The Company continues to focus on evaluating IDE397 in two trials in select monotherapy indications and in high conviction clinical combinations: IDE397-001 (NCT04794699) is a Phase 2 monotherapy expansion of IDE397 in MTAP-deletion NSCLC and bladder cancer. Selected a move-forward Phase 2 expansion dose for IDE397 monotherapy in MTAP-deletion squamous NSCLC, based on adverse event profile and preliminary clinical efficacy observed, including multiple partial responses by RECIST 1.1 in squamous NSCLC. MTAP-deletion squamous NSCLC is estimated to have a global annual incidence greater than 100,000 patients. Multiple partial responses by RECIST 1.1 have also been observed in MTAP-deletion bladder cancer with IDE397 monotherapy and evaluation is ongoing for further potential Phase 2 expansion in this tumor type. Phase 1/2 trial of IDE397 + AMG 193 in MTAP-Deletion NSCLC (Amgen-sponsored study, NCT05975073): Enrollment is ongoing in the dose escalation portion. Joint publication strategy on IDE397 and AMG 193 combination targeted in 2024 Phase 1 trial of IDE397 + Trodelvy in MTAP-deletion bladder cancer (IDEAYA-sponsored, NCT04794699). Trial initiation activities for the IDE397 and Trodelvy clinical combination are ongoing and the dosing of a first patient is anticipated in mid-year (second or third quarter) 2024. IDE161 Program in Tumors with Homologous Recombination Deficiency IDE161 is a potential first-in-class inhibitor of poly(ADP-ribose) glycohydrolase (PARG), a novel, mechanistically distinct target in the same clinically validated biological pathway as poly(ADP-ribose) polymerase (PARP). IDE161 received two FDA Fast Track designations in platinum-resistant advanced or metastatic ovarian cancer patients having tumors with BRCA1/2 mutations, and in pretreated advanced or metastatic HR+, Her2-, BRACA1/2 mutant breast cancer. IDE161 is currently being evaluated in IDE161-001 (NCT05787587), a Phase 1/2 trial of IDE161 in solid tumors with HRD. Early clinical data from the dose escalation cohorts were reported and the Phase 1 dose optimization portion of the trial is ongoing with the goal to select an initial Phase 2 expansion dose. Solid tumor types of focus, include ER+ HER-breast, colorectal, endometrial, and prostate cancers. Selection of an initial Phase 2 monotherapy expansion dose in HRD solid tumors is targeted in the second half of 2024. The Company is currently validating IDE161 combination opportunities preclinically and targeting identification of additional combination(s) in 2024. In March 2024, the Company entered into the Clinical Trial Collaboration and Supply Agreement with MSD International Business GmbH, a subsidiary of Merck & Co., Inc. Rahway, NJ, USA. The Company is planning to evaluate IDE161 in a combination study with KEYTRUDA in patients with MSI-high and MSS endometrial cancer. A first-patient-in for this study is targeted in the second half of 2024. KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA. GSK-Partnered Programs GSK101 (IDE705) Program in Tumors with HRD GSK101 (IDE705) is a potential first-in-class small molecule inhibitor of Pol Theta Helicase being developed as a combination treatment with niraparib for advanced solid tumors with HRD. IND clearance was obtained from the FDA to enable the GSK-sponsored Phase 1/2 clinical trial to evaluate GSK101 in combination with niraparib, the GSK small molecule inhibitor of PARP, for patients having solid tumors with BRCA or other HR mutations, or with HRD. GSK is the sponsor of the Phase 1/2 clinical trial. GSK has dosed the first patient and enrollment is ongoing in the dose escalation portion of this study. Upon initiation of the Phase 1 dose expansion trial, IDEAYA will be eligible to receive a $10.0 million milestone payment, with the collaboration having a potential further aggregate later-stage development and regulatory milestones of up to $465.0 million. GSK is responsible for all research and development costs for the program. Upon commercialization, IDEAYA will be eligible to receive up to $475 million of commercial milestones, and tiered royalties on global net sales of GSK101 – ranging from high single-digit to sub-teen double-digit percentages, subject to certain customary reductions. Werner Helicase Inhibitor in Tumors with High Microsatellite Instability IDEAYA and GSK are on track for an IND filing later in 2024 for the selected Werner Helicase inhibitor announced in December 2023. The IND-enabling GLP toxicology studies have been completed for the Werner Helicase inhibitor development candidate. IDEAYA has the potential to earn up to an additional $17.0 million in aggregate milestones through early Phase 1, including $7.0 million upon IND clearance, and is entitled to receive up to $465.0 million in further later-stage development and regulatory milestones. GSK is responsible for 80% of global research and development costs and IDEAYA is responsible for 20% of such costs. Upon commercialization, IDEAYA will be eligible to receive up to $475 million of commercial milestones, 50% of U.S. net profits and tiered royalties on global non-U.S. net sales of the Werner Helicase Inhibitor DC – ranging from high single-digit to sub-teen double-digit percentages, subject to certain customary reductions. Next-Generation Precision Medicine Pipeline Programs Early preclinical research programs focused on pharmacological inhibition of several new targets for patients with solid tumors characterized by defined biomarkers based on genetic mutations and/or molecular signatures are ongoing. These programs have the potential for discovery and development of first-in-class or best-in-class therapeutics with multiple wholly owned development candidate nominations targeted in the second half of 2024, including in MTAP-deletion solid tumors indications to enable potential wholly-owned clinical combination with IDE397. Financial Results As of March 31, 2024, IDEAYA had cash, cash equivalents and marketable securities totaling $941.4 million. This compared to cash, cash equivalents and marketable securities of $632.6 million as of December 31, 2023. The increase was primarily attributable to net proceeds of $343.5 million from the sale of shares of its common stock through ATM offerings during the period from January 1, 2024 to March 31, 2024, offset by net cash used in operations. Subsequent to March 31, 2024, the Company raised gross proceeds of approximately $37.2 million, before deducting underwriting discounts and commissions and other offering expenses, from the sale of shares of its common stock through ATM offerings in April 2024, generating net proceeds of approximately $36.5 million, after deducting underwriting discounts and commissions and other estimated offering expenses. There was no collaboration revenue recognized for the three months ended March 31, 2024 compared to $3.9 million for the three months ended December 31, 2023. We completed all performance obligations related to the upfront payment under the GSK collaboration agreement as of December 31, 2023. Future collaboration revenue recognized under the GSK collaboration agreement will be related to future milestone payments as they are earned. Research and development (R&D) expenses for the three months ended March 31, 2024 totaled $42.8 million compared to $38.8 million for the three months ended December 31, 2023. The increase was primarily due to higher clinical trial and personnel-related expenses. General and administrative (G&A) expenses for the three months ended March 31, 2024 totaled $8.2 million compared to $7.1 million for the three months ended December 31, 2023. The increase was primarily due to higher personnel-related expenses to support our growth. The net loss for the three months ended March 31, 2024 was $39.6 million compared to the net loss of $34.0 million for the three months ended December 31, 2023. Total stock compensation expense for the three months ended March 31, 2024 was $6.3 million compared to $4.8 million for the three months ended December 31, 2023. About IDEAYA Biosciences IDEAYA is a precision medicine oncology company committed to the discovery and development of targeted therapeutics for patient populations selected using molecular diagnostics. IDEAYA's approach integrates capabilities in identifying and validating translational biomarkers with drug discovery to select patient populations most likely to benefit from its targeted therapies. IDEAYA is applying its research and drug discovery capabilities to synthetic lethality – which represents an emerging class of precision medicine targets. IDEAYA's updated corporate presentation is available on its website, at its Investor Relations page: . Forward-Looking Statements This press release contains forward-looking statements, including, but not limited to, statements related to (i) the timing, content and venue of clinical program updates, (ii) the timing for the development of a joint Amgen/IDEAYA publication strategy, (iii) the timing of a first-patient-in in the IDE397 and Trodelvy combination study, (iv) the timing of initial Phase 2 expansion for IDE161 in HRD solid tumors, (v) the timing of a first-patient-in in the IDE161 and KEYTRUDA combination study, (vi) the timing of IND submission for the Werner Helicase inhibitor DC, (vii) the timing of designation of next generation development candidates, (viii) the extent to which IDEAYA's existing cash, cash equivalents, and marketable securities will fund its planned operations, (ix) the estimate of patient populations, (x) additional clinical combinations, and (xi) the receipt of development and regulatory milestones. 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 20, 2024 and any current and periodic reports filed with the U.S. Securities and Exchange Commission. Investor and Media Contact IDEAYA Biosciences Andres Ruiz Briseno SVP, Head of Finance and Investor Relations [email protected] SOURCE IDEAYA Biosciences, Inc.