Form 8-K

8-K — IDEAYA Biosciences, Inc.

Accession: 0001193125-26-251399

Filed: 2026-06-01

Period: 2026-06-01

CIK: 0001676725

SIC: 2834 (PHARMACEUTICAL PREPARATIONS)

Item: Regulation FD Disclosure

Item: Other Events

Item: Financial Statements and Exhibits

Documents

8-K — d138848d8k.htm (Primary)

EX-99.1 (d138848dex991.htm)

GRAPHIC (g138848ex99_1s10g1.jpg)

GRAPHIC (g138848ex99_1s11g1.jpg)

GRAPHIC (g138848ex99_1s12g1.jpg)

GRAPHIC (g138848ex99_1s13g1.jpg)

GRAPHIC (g138848ex99_1s14g1.jpg)

GRAPHIC (g138848ex99_1s15g1.jpg)

GRAPHIC (g138848ex99_1s16g1.jpg)

GRAPHIC (g138848ex99_1s17g1.jpg)

GRAPHIC (g138848ex99_1s1g1.jpg)

GRAPHIC (g138848ex99_1s2g1.jpg)

GRAPHIC (g138848ex99_1s3g1.jpg)

GRAPHIC (g138848ex99_1s4g1.jpg)

GRAPHIC (g138848ex99_1s5g1.jpg)

GRAPHIC (g138848ex99_1s6g1.jpg)

GRAPHIC (g138848ex99_1s7g1.jpg)

GRAPHIC (g138848ex99_1s8g1.jpg)

GRAPHIC (g138848ex99_1s9g1.jpg)

XML — IDEA: XBRL DOCUMENT (R1.htm)

8-K

8-K (Primary)

Filename: d138848d8k.htm · Sequence: 1

8-K

false 0001676725 0001676725 2026-06-01 2026-06-01

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 1, 2026

IDEAYA Biosciences, Inc.

(Exact name of registrant as specified in its charter)

Delaware

001-38915

47-4268251

(State or other jurisdiction

of incorporation)

(Commission

File Number)

(IRS Employer

Identification Number)

5000 Shoreline Court, Suite 300

South San Francisco, California 94080

(Address of principal executive offices, including Zip Code)

Registrant’s telephone number, including area code: (650) 443-6209

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐

Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐

Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐

Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading

Symbol

Name of each exchange

on which registered

Common Stock, $0.0001 par value per share

IDYA

The Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 7.01

Regulation FD Disclosure.

On June 1, 2026, IDEAYA Biosciences, Inc. (the “Company”) presented an investor presentation in connection with the 2026 American Society of Clinical Oncology (“ASCO”) Annual Meeting. A copy of the presentation is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

The information in this Item 7.01, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Item 8.01

Other Events.

IDEAYA Biosciences and Servier Provide Complete Data from Phase 2/3 Registrational OptimUM-02 Trial of the Darovasertib Combination in First Line HLA*A2:01 Negative Metastatic Uveal Melanoma in a Late-Breaking Oral Presentation at ASCO

On June 1, 2026, the Company and Les Laboratoires Servier (“Servier”) presented complete data from the primary analysis of their registrational Phase 2/3 OptimUM-02 trial of darovasertib in combination with crizotinib (“darovasertib combination”) in first line (“1L”) HLA*A2:01 negative metastatic uveal melanoma (“mUM”) at ASCO. The data were provided in a late-breaking oral presentation by Dr. Marlana Orloff, M.D., Professor of Medical Oncology at Thomas Jefferson University Hospital and lead investigator on the trial.

OptimUM-02 is a global, registrational Phase 2/3 trial evaluating a total of 313 patients with 1L HLA*A2:01 negative mUM, randomized 2:1 to the darovasertib combination or an investigator’s choice of therapy (“ICT”) arm reflective of real-world clinical practice that included ipilimumab plus nivolumab or pembrolizumab. The primary endpoint to support accelerated approval is median progression-free survival (“PFS”) as assessed by blinded independent central review (“BICR”). Secondary endpoints include safety and investigator assessed PFS, overall response rate (“ORR”), disease control rate (“DCR”) and duration of response. Data presented at ASCO were as of a cutoff date of January 23, 2026 and included additional detail on baseline characteristics as well as safety, secondary endpoints and median PFS across patient subgroups.

Key Findings from OptimUM-02

•

Primary endpoint (Phase 2 portion): progression free survival by BICR

•

The trial met the primary endpoint, with patients treated with the darovasertib combination demonstrating a statistically significant improvement in median PFS of 6.9 months versus 3.1 months in the ICT arm by BICR (HR: 0.42; 95% CI: 0.30, 0.59; p-value: <0.0001).

•

Patients treated with the darovasertib combination also had a statistically significant improvement in median PFS of 6.7 months versus 2.7 months for ICT by investigator assessment (HR: 0.36; 95% CI: 0.26, 0.50, p-value: <0.0001).

•

Notably, the darovasertib combination reduced the risk of disease progression by 58% and 64% as assessed by BICR and investigator assessment, respectively.

•

Treatment with the darovasertib combination demonstrated a consistent and meaningful improvement in median PFS relative to the ICT arm across a broad range of patient subgroups, including age and gender, type of immune therapy used in ICT, LDH stratification, ECOG status and site of metastasis.

•

Secondary endpoints: ORR, DCR, duration of response

•

Patients treated with the darovasertib combination had an ORR of 37.1% (78/210) and 39.5% (83/210) as assessed by BICR and investigator, respectively, compared to 5.8% (6/103) and 1.9% (2/103) in the ICT arm (p-value: <0.0001).

•

The darovasertib combination led to a disease control rate of 73.3% (154/210) and 74.3% (156/210) by BICR and investigator assessment, respectively, compared to 31.1% (32/103) and 27.2% (28/103) in the ICT control arm.

•

The median duration of response was 6.8 months (95% CI: 5.5, 11.3) by BICR and 6.8 months (95% CI: 4.8, 9.7) by investigator assessment based on a median follow-up time of 7.4 months as of the cutoff date.

•

Overall survival (Primary endpoint of the Phase 3 portion)

•

As noted in the topline results, data on overall survival (“OS”) was still immature as of the cutoff date, however, there was an early trend in OS improvement in the darovasertib combination arm relative to the ICT arm.

•

The Company will provide the next OS update as part of the pre-specified interim analysis. Overall survival data, when available, will be used to support a potential full approval in the United States and globally.

•

Safety

•

The darovasertib combination was generally well-tolerated with a manageable safety profile consistent with previous results and known side-effects of each agent alone.

•

Median relative dose intensities of darovasertib and crizotinib were 91.0% and 77.1%, respectively, compared to 100% for the ICT arm.

•

Grade 3/4 treatment-related adverse events (“TRAEs”) occurred in 40.6% (97/239) of patients in the darovasertib combination arm compared to 37.0% (37/100) of patients in the ICT control arm.

•

Treatment-related serious adverse events were 9.2% (22/239) and 25.0% (25/100) in the darovasertib combination and ICT arms, respectively.

•

Low discontinuation rate due to TRAEs for darovasertib (2.5%) and crizotinib (10.0%) relative to ICT (19.0%).

•

The most common Grade 3/4 TRAEs included diarrhea (10.0%), syncope (7.1%) and hypotension (3.8%) in the darovasertib combination arm compared to elevated liver enzymes (ALT, 7.0% / AST, 7.0%), diarrhea (6.0%), hepatitis (5.0%) and colitis (4.0%) in the ICT control arm.

In April 2026, the Company announced the U.S. Food and Drug Administration (“FDA”) has agreed to review its new drug application (“NDA”) for darovasertib in combination with crizotinib under the Oncology Center of Excellence Real-Time Oncology Review program. This program allows applicants to pre-submit components of their NDA to allow the FDA to review clinical trial data before the complete filing is submitted and aims to provide a more efficient review process to ensure safe and effective treatments are available to patients as early as possible. The Company completed its first pre-submission in May and expects to complete the NDA filing in the second half of 2026.

Item 9.01

Financial Statements and Exhibits.

(d) Exhibits.

Exhibit

No.

Description

99.1

ASCO Presentation, dated June 1, 2026.

104

Cover Page Interactive Data File (embedded within the Inline XBRL document).

Forward-Looking Statements

Certain statements contained herein are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Such forward-looking statements include, but are not limited to, statements regarding: (i) the potential therapeutic benefit, safety, tolerability and clinical activity of darovasertib in combination with crizotinib; (ii) the potential significance and implications of data from the Phase 2/3 registrational OptimUM-02 trial; (iii) expectations regarding overall survival analyses and timing of interim data updates; (iv) the Company’s plans and expectations regarding regulatory submissions, including the timing and completion of the NDA submission under the FDA’s Real-Time Oncology Review program; (v) the potential for accelerated approval and/or full approval of darovasertib in combination with crizotinib in the United States and globally; and (vi) the Company’s strategy, business plans and objectives. Such forward-looking statements are based on the Company’s current expectations, estimates, assumptions, and beliefs regarding future events and are subject to substantial risks and uncertainties that could cause actual results, outcomes or events to differ materially from those expressed or implied by such statements. These risks and uncertainties include, among others: risks related to the discovery, development and regulatory approval of drug candidates; risks related to the timing, progress and results of clinical trials, including uncertainties regarding enrollment, safety, efficacy and durability of response; risks that clinical trial results may not be replicated in future studies or support regulatory approval; risks related to regulatory interactions, submissions and decisions, including the timing and outcome of NDA review processes; risks related to manufacturing and supply; risks related to competition and changes in the standard of care; the timing and success of commercialization efforts; the outcome of collaborations and licensing arrangements; the Company’s dependence on third parties; and risks related to the Company’s ability to obtain, maintain, protect and enforce intellectual property rights for its product candidates. All forward-looking statements are made as of the date hereof, and the Company undertakes no obligation to update any forward-looking statements to reflect new information, future events, or otherwise, except as required by law. 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 the Company in general, see the Company’s Annual Report on Form 10-K dated February 17, 2026, the Company’s Quarterly Report on Form 10-Q dated May 5, 2026, and any subsequently filed current and periodic reports filed or furnished with the Securities and Exchange Commission.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

IDEAYA BIOSCIENCES, INC.

Date: June 1, 2026

By:

/s/ Yujiro Hata

Yujiro Hata

President and Chief Executive Officer

EX-99.1

Filename: d138848dex991.htm · Sequence: 2

EX-99.1

Darovasertib Plus Crizotinib vs

Investigator’s Choice as First-Line Treatment for Patients with HLA-A2 Negative Metastatic Uveal Melanoma: Primary Results from the OptimUM-02 Trial Marlana Orloff,1 Egle Ramelyte,2 Marcus O. Butler,3 Piotr Rutkowski,4 Lorenza Di Guardo,5

Matteo S. Carlino,6 Bartosz Chmielowski,7 Lucy Kennedy,8 Kamaneh Montazeri,9 Joseph Sacco,10 Ernesto Rossi,11 Victoria Atkinson,12 Rizwan Haq,13 Meredith McKean,14 George Cole,15 Hetal Patel,15 Long Kwei,15 Jasgit Sachdev,15 Darrin M Beaupre,15

Sophie Piperno-Neumann16 Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor 1. Thomas Jefferson University Hospital, Philadelphia PA, United States. 2. Department of Dermatology University

Hospital Zurich, Zurich, Switzerland. 3. Princess Margaret Cancer Centre, Departments of Medicine and Immunology, University of Toronto Toronto, Canada. 4. Maria Sklodowska-Curie National Research Institute of Oncology Warsaw Poland. 5. Fondazione

IRCCS Istituto Nazionale dei Tumori di Milano, Milan, Italy. 6. Westmead and Blacktown Hospitals, The University of Sydney and the Melanoma Institute, Westmead, Australia. 7. Jonsson Comprehensive Cancer Center, University of California Los Angeles,

Los Angeles, CA, United States. 8. Cleveland Clinic Foundation -Taussig Cancer Center, Cleveland, OH, United States. 9. Massachusetts General Hospital, Boston, MA, United States. 10. The Clatterbridge Cancer Centre NHS Foundation Trust, Birkenhead,

Wirral, United Kingdom. 11. Fondazione Policlinico Universitario A.Gemelli IRCCS, Rome, Italy. 12. Princess Alexandra Hospital, Brisbane Australia. University of Queensland. 13. Dana-Farber Cancer Institute, Boston, MA United States. 14. Sarah

Cannon Research Institute, Nashville, TN, United States. 15. IDEAYA Biosciences, South San Francisco, CA, United States. 16. Institut Curie Research University, Paris, France. Exhibit 99.1

HLA, human leukocyte antigen. mOS,

median overall survival. mPFS, median progression free survival. PKC, protein kinase C. 1. Khoja L, et al. J Clin Oncol. 2025;43(suppl) [abstract 9539]. 2. Rantala ES, et al. Melanoma Res. 2019;29:561-568. 3. Park JJ, et al. Oncogenesis. 2024;13:9.

4. Sullivan RJ, Shoushtari AN. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. Available from: https://www.uptodate.com/contents/the-molecular-biology-of-melanoma (Accessed on May 21, 2025) 5. Piperno-Neumann S, et al. Br J Cancer.

2023;128:1040-1051. 6. McKean M et al. Presented at 2025 SMR Congress. Erlangen, Germany [abstract 209]. Uveal melanoma (UM) is the most common ocular cancer in adults Despite effective primary tumor treatment up to 50% of patients develop

metastases Metastatic UM (mUM) has a poor prognosis with mPFS of 2.8 months and mOS of 10-12 months1-2 Mutations in GNAQ/11 that activate PKC are detected in >95% of uveal melanoma tumors3-4 Currently no FDA-approved treatments for

HLA-A*02:01 negative mUM patients OptimUM-01: encouraging activity across both HLA-A*02:01-positive and negative mUM with darovasertib + crizotinib5-6 OptimUM-02: evaluated darovasertib in combination with crizotinib as first-line therapy in

patients with HLA-A*02:01–negative mUM Darovasertib: first-in-class, oral, PKC inhibitor with clinical activity in HLA-A*02:01-positive and negative mUM5 Crizotinib: oral MET inhibitor, has shown complementary activity with darovasertib

preclinically and clinically6 Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor Darovasertib: First-in-Class, Oral Targeted PKC Inhibitor Targeting PKC and MET in Metastatic Uveal Melanoma

OptimUM-02 Study Design Phase 2/3,

multi-center, multi-arm, multi-stage, open-label study Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor Primary: PFS by BICR Secondary: PFS by Investigator ORR by BICR, Investigator Duration

of response Disease Control Rate ≥ 12 weeks Safety Phase 2b Endpoints Primary: Overall Survival (to be presented at later date when data matures) Phase 3 Endpoints Phase 2a* Phase 2b and Phase 3* # Patients will be stratified by baseline LDH

(≤ULN vs >ULN, but less than 2-fold the ULN vs ≥ 2-fold the ULN) and investigator’s choice of comparator treatment (ipilimumab + nivolumab vs single-agent therapy). * Treatment will continue until disease progression, death (any

cause), unacceptable toxicity or treatment discontinuation **Treatment will commence with a 7-day run-in of darovasertib monotherapy (at dose corresponding to the treatment arm, and the run-in may be extended if clinically indicated) prior to

starting crizotinib. BICR, blinded independent central reader. Dacarbazine, dacarbazine (1000 mg/m2 Q3W). Ipi+Nivo, ipilimumab (3 mg/kg) + nivolumab (1 mg/kg) for 4 cycles followed by nivolumab (1mg/kg). ORR, objective response rate. Pembro,

pembrolizumab (200 mg Q3W). PFS, progression-free survival. 2:2:1 R# 2:1 R# Treatment naïve HLA-A*02:01 negative mUM Patients: Darovasertib (300 mg BID)** + Crizotinib (200 mg BID) Darovasertib (200 mg BID)** + Crizotinib (200 mg BID)

Darovasertib (300 mg BID)** + Crizotinib (200 mg BID) Investigator’s Choice (control): 1. Pembrolizumab 2. Ipilimumab + Nivolumab 3. Dacarbazine Investigator’s Choice (control): 1. Pembrolizumab 2. Ipilimumab + Nivolumab 3.

Dacarbazine

Analysis Populations Efficacy All

patients in the ITT population setting (phase 2b portion of trial) Darovasertib 300 mg + crizotinib 200 mg (n=210) Investigator’s Choice (control, n=103) Analysis based on both BICR and Investigator assessments Safety Safety was evaluated in

all patients (phase 2a and 2b) who received at least one dose of darovasertib 300 mg + crizotinib 200 mg or control Darovasertib 300mg + crizotinib 200 mg (N=239) Investigator’s Choice (control, N=100) Marlana Orloff, MD. Alexander &

Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor BICR, blinded independent central reader. ITT, intent-to-treat.

Primary Endpoint Statistical Analysis

PFS per BICR 130 PFS events were required to detect a hazard ratio of 0.55 with 90% power Stratified log-rank test at a 1-sided α of 2.5% The median PFS in the control arm was assumed to be 3 months The target HR of 0.55 represents a 45%

reduction in the risk of disease progression or death Translates to approximately 5.5 months median PFS in the darovasertib + crizotinib arm assuming exponential distributions Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical

Director in Uveal Melanoma; Professor BICR, blinded independent central reader. HR, hazard ratio. ORR, objective response rate. PFS, progression-free survival.

Baseline Characteristics Efficacy

Analysis Population Darovasertib + Crizotinib (N=210) Investigator’s Choice (N=103) Age, mean (range) 61.1 (22 - 85) 61.5 (29 - 85) Female, n (%) 101 (48.1) 52 (50.5) Race, n (%) White 177 (84.3) 83 (80.6) non-White 4 (1.9) 4 (3.9) Not

reported 29 ( 13.8) 16 ( 15.5) ECOG 0 162 (77.1) 87 (84.5) 1 48 (22.9) 16 (15.5) Stratification LDH at Baseline (IRT) , n (%) ≤ ULN 120 (57.1) 62 (60.2) > ULN - < 2x ULN 65 (31.0) 29 (28.2) ≥ 2x ULN 25 (11.9) 12 (11.7)

Stratification ICT at Baseline (IRT) , n (%) Ipilimumab + nivolumab 79 ( 76.7) Pembrolizumab or dacarbazine* 24 ( 23.3) Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor *No patients received

dacarbazine in the investigator’s choice arm

Baseline Tumor Characteristics

Efficacy Analysis Population Darovasertib + Crizotinib (N=210) Investigator’s Choice (N=103) Time since First Metastatic Diagnosis (year) n 210 103 Median (range) 0.18 (0.0 – 8.1) 0.19 (0.0 – 4.6) Size of Largest Metastatic Lesion

Category ≤ 3 cm 119 ( 56.7) 67 ( 65.0) 3.1 - 8.0 cm 73 ( 34.8) 31 ( 30.1) ≥ 8.1 cm 18 ( 8.6) 5 ( 4.9) Metastatic Sites, n (%) Hepatic disease only 127 ( 60.5) 65 ( 63.1) Extrahepatic disease only 11 ( 5.2) 7 ( 6.8) Hepatic and

extrahepatic disease 72 ( 34.3) 31 ( 30.1) Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor

Primary Efficacy Endpoint Results BICR

Assessment Investigator Assessment Clinically meaningful and statistically significant improvement in PFS with darova + criz vs control Reduction in the risk of progression or death: 58% by BICR (HR: 0.42); 64% by investigator assessment (HR: 0.36),

p < 0.0001 Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor Median follow-up for the population was 7.4 months. Median duration of treatment for darovasertib and crizotinib was 6.31

months; for pembrolizumab, ipilimumab, and nivolumab, the median duration of treatment were 2.87, 2.56, and 2.79 months, respectively. BICR, blinded independent central reader. Darova + criz, darovasertib + crizotinib. HR, hazard ratio. PFS,

progression free survival. HR = 0.42 (0.30, 0.59) p-value: <0.0001 + Censored HR = 0.36 (0.26, 0.50) p-value: <0.0001 + Censored Control Control Darova + Criz Darova + Criz Darova + Criz Darova + Criz Median (95% CI) Darova + Criz: 6.9 (5.6,

8.3) Control: 3.1 (1.8, 4.2) Median (95% CI) Darova + Criz: 6.7 (5.6, 8.2) Control: 2.7 (1.7, 4.1)

Secondary Efficacy Endpoint Results

Darovasertib + Crizotinib (N=210) Investigator’s Choice (N=103) Darovasertib + Crizotinib (N=210) Investigator’s Choice (N=103) Objective Response Rate Patients with a complete or partial response, n (%) 78 (37.1) 6 (5.8) 83 (39.5) 2

(1.9) 95% CI 30.6, 44.1 2.2, 12.3 32.9, 46.5 0.2, 6.8 Odds ratio (95% CI) 10.8 (4.4, 26.4) 34.6 (8.1, 146.9) p-value vs. control <0.0001 <0.0001 Duration of Response Median, months (95% CI) 6.8 (5.5, 11.3) NE 6.8 (4.8, 9.7) NE

Disease Control Rate Patients with a complete response, partial response, or stable disease for at least 12 weeks, n (%) 154 (73.3) 32 (31.1) 156 (74.3) 28 (27.2) 95% CI 66.8, 79.2 22.3, 40.9 67.8, 80.1 18.9, 36.8 Odds ratio (95% CI) 7.7 (4.3, 13.5)

9.5 (5.3, 17.0) p-value vs. control <0.0001 <0.0001 BICR Assessment Investigator Assessment Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor BICR, blinded independent central reader.

CI, confidence interval.

Best Overall Response Darovasertib

+ Crizotinib (N=210) Investigator’s Choice (N=103) Darovasertib + Crizotinib (N=210) Investigator’s Choice (N=103) Best Overall Response, n (%) Complete Response 5 (2.4) 0 0 0 Partial Response 73 (34.8) 6 (5.8) 83 (39.5) 2

(1.9) Stable Disease 107 (51.0) 43 (41.7) 99 (47.1) 39 (37.9) Progressive Disease 13 (6.2) 29 (28.2) 15 (7.1) 34 (33.0) Non-Evaluable by RECIST 0 1 (1.0) 1 (0.5) 4 (3.9) Not Reported* 12 (5.7) 24 (23.3) 12 (5.7) 24 (23.3) BICR Assessment

Investigator Assessment * Refers to the patients who did not have any post-baseline assessments. Investigator Choice Treatment: (24): withdrew consent before treatment (17), before 1st post-baseline scan (2); due to AE (1, G3 hypoxia), clinical

progression (1) and death (2), scan not recoverable from outside facility (1). Darovasertib + crizotinib Treatment: (12); due to death (7), withdrew consent before 1st post-baseline scan (1); due to clinical progression (1), scans performed after

clinical cutoff (1), scans not performed at EOT or during post-treatment period (2). BICR, blinded independent central reader. CI, confidence interval. Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma;

Professor

Best Overall Response BICR

Assessment Investigator Assessment BICR, blinded independent central reader. CR, complete response. NR, not reported. PD, progressive disease. PR, partial response. SD, stable disease. Marlana Orloff, MD. Alexander & Johnston Family Endowed

Clinical Director in Uveal Melanoma; Professor Darovasertib + Crizotinib Darovasertib + Crizotinib Control Control

Hazard Ratio (95% CI) Darova+Criz

− Control Results by BICR. Unstratified model. BICR, blinded independent central reader. Control, investigator’s choice of treatments. Daca, dacarbazine. Darova + Criz, darovasertib 300mg + crizotinib 200mg. ECOG, Eastern Cooperative

Oncology Group. Ipi, ipilimumab. LDH, lactate dehydrogenase. Nivo, nivolumab. Pem, pembrolizumab. PFS, progression-free survival. ULN, upper limit of normal. Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal

Melanoma; Professor Favors Darovasertib + Crizotinib Favors Control Primary Endpoint Results: PFS Subgroup Analysis Results consistent across a broad range of patients Participants Darova+Criz, Control 210, 103 120, 62 65, 29 25, 12 158, 79 52, 24

118, 64 92, 39 101, 52 109, 51 177, 83 33, 20 162, 87 48, 16 74, 36 136, 67 119, 67 73, 31 18, 5 127, 65 11, 7 72, 31

Marlana Orloff, MD. Alexander &

Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor Darovasertib + Crizotinib (N=239) Investigator’s Choice (N=100) Median Relative Dose Intensity 91.0% for Darovasertib 77.1% for Crizotinib 100% Any TRAE, n (%) 235 (98.3)

89 (89.0) Grade 3 or 4 97 (40.6) 37 (37.0) Grade 5* 1 (0.4) 1 (1.0) Treatment related-SAE 22 (9.2) 25 (25.0) Leading to withdrawn 2 (0.8) 5 (5.0) Leading to darovasertib withdrawn 6 (2.5) - Leading to crizotinib withdrawn 24 (10.0) - Leading to IC

withdrawn - 19 (19.0) Leading to darovasertib dose reduced 56 (23.4) - Leading to crizotinib dose reduced 63 (26.4) - Leading to IC dose reduced - 0 * Grade 5 SAEs: Hepatic failure in the darovasertib + crizotinib arm in a subject with extensive

bulky liver metastases in both lobes considered unrelated by Sponsor; gastrointestinal hemorrhage in ICT arm Overall Treatment Related Adverse Event Summary IC, investigator’s choice. SAE, serious adverse events. TRAE, treatment-related

adverse events.

Most Common Treatment Related

Adverse Events All Grades Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor Darovasertib + Crizotinib (N=239) Any TRAEs (≥20%), n (%) 235 ( 98.3) Diarrhea 203 ( 84.9) Nausea 179 ( 74.9)

Peripheral edema 160 ( 66.9) Vomiting 119 ( 49.8) Dermatitis acneiform 100 ( 41.8) Fatigue 94 ( 39.3) Hypotension 79 ( 33.1) Hypoalbuminemia 61 ( 25.5) Dysgeusia 61 ( 25.5) Dizziness 61 ( 25.5) Decreased appetite 57 ( 23.8) Investigator’s

Choice (N=100) Any TRAEs (≥20%), n (%) 88 ( 88.0) Diarrhea 29 ( 29.0) Alanine aminotransferase increased 25 ( 25.0) Aspartate aminotransferase increased 25 ( 25.0) Fatigue 25 ( 25.0) Nausea 25 ( 25.0) Pruritus 24 ( 24.0) TRAEs,

treatment-related adverse events.

Grade 3/4 Treatment Related Adverse

Events Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor Darovasertib + Crizotinib (N=239) Any Grade 3/4 Adverse Events (≥2%), n (%) 97 ( 40.6) Diarrhea 24 ( 10.0) Syncope 17 ( 7.1)

Hypotension 9 ( 3.8) Nausea 7 ( 2.9) Peripheral edema 7 ( 2.9) Anemia 6 ( 2.5) Investigator’s Choice (N=100) Any Grade 3/4 Adverse Events (≥2%), n (%) 37 ( 37.0) Alanine aminotransferase increased 7 ( 7.0) Aspartate aminotransferase

increased 7 ( 7.0) Diarrhea 6 ( 6.0) Hepatitis 5 ( 5.0) Colitis 4 ( 4.0) Lipase increased 3 ( 3.0) Autoimmune hepatitis 3 ( 3.0) Amylase increased 3 ( 3.0) Tubulointerstitial nephritis 2 ( 2.0) Hypophysitis 2 ( 2.0) Hyperthyroidism 2 ( 2.0) TRAEs,

treatment-related adverse events.

Summary In patients with

HLA-A2-negative-mUM treated in the first-line setting, darovasertib +crizotinib demonstrated: Clinically meaningful and significantly longer PFS vs investigator’s choice (mPFS of 6.9 months vs 3.1 months, HR 0.42, indicating a 58% reduction in

disease progression or death) Significantly improved ORR (37.1% vs 5.8%) and DCR (73.3% vs. 31.1%) by BICR compared with the investigator’s choice treatment, the majority (76.7%) were treated with ipilimumab + nivolumab OS data is not yet

mature; however, an early trend toward improved OS was observed with the darovasertib combination arm versus ICT. OS data will be presented at a future date AEs consistent with prior safety profile, with low rate of TR-SAEs (9.2%) and

discontinuations due to TRAEs for darovasertib and crizotinib (2.5 and 10% respectively) Marlana Orloff, MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor The OptimUM-02 results support a potential new

therapeutic standard for a disease with limited treatment options and poor prognosis BICR, blinded independent central reader. IC, investigator’s choice. DCR, disease control rate. HLA, human leukocyte antigen. HR, hazard ratio. mPFS, median

progression free survival. mUM, metastatic uveal melanoma. ORR, objective response rate. TR-SAE, treatment-related serious adverse events. TRAE, treatment-related adverse events.

Acknowledgements Marlana Orloff,

MD. Alexander & Johnston Family Endowed Clinical Director in Uveal Melanoma; Professor We gratefully acknowledge the Patients and their families for participating in this study, and all investigators and site staff whose contributions made the

OptimUM-02 study possible

GRAPHIC

Filename: g138848ex99_1s10g1.jpg · Sequence: 6

Binary file (128197 bytes)

Download g138848ex99_1s10g1.jpg

GRAPHIC

Filename: g138848ex99_1s11g1.jpg · Sequence: 7

Binary file (105340 bytes)

Download g138848ex99_1s11g1.jpg

GRAPHIC

Filename: g138848ex99_1s12g1.jpg · Sequence: 8

Binary file (116401 bytes)

Download g138848ex99_1s12g1.jpg

GRAPHIC

Filename: g138848ex99_1s13g1.jpg · Sequence: 9

Binary file (140003 bytes)

Download g138848ex99_1s13g1.jpg

GRAPHIC

Filename: g138848ex99_1s14g1.jpg · Sequence: 10

Binary file (117891 bytes)

Download g138848ex99_1s14g1.jpg

GRAPHIC

Filename: g138848ex99_1s15g1.jpg · Sequence: 11

Binary file (116605 bytes)

Download g138848ex99_1s15g1.jpg

GRAPHIC

Filename: g138848ex99_1s16g1.jpg · Sequence: 12

Binary file (149879 bytes)

Download g138848ex99_1s16g1.jpg

GRAPHIC

Filename: g138848ex99_1s17g1.jpg · Sequence: 13

Binary file (114793 bytes)

Download g138848ex99_1s17g1.jpg

GRAPHIC

Filename: g138848ex99_1s1g1.jpg · Sequence: 14

Binary file (181847 bytes)

Download g138848ex99_1s1g1.jpg

GRAPHIC

Filename: g138848ex99_1s2g1.jpg · Sequence: 15

Binary file (170864 bytes)

Download g138848ex99_1s2g1.jpg

GRAPHIC

Filename: g138848ex99_1s3g1.jpg · Sequence: 16

Binary file (141897 bytes)

Download g138848ex99_1s3g1.jpg

GRAPHIC

Filename: g138848ex99_1s4g1.jpg · Sequence: 17

Binary file (96287 bytes)

Download g138848ex99_1s4g1.jpg

GRAPHIC

Filename: g138848ex99_1s5g1.jpg · Sequence: 18

Binary file (97655 bytes)

Download g138848ex99_1s5g1.jpg

GRAPHIC

Filename: g138848ex99_1s6g1.jpg · Sequence: 19

Binary file (119700 bytes)

Download g138848ex99_1s6g1.jpg

GRAPHIC

Filename: g138848ex99_1s7g1.jpg · Sequence: 20

Binary file (96809 bytes)

Download g138848ex99_1s7g1.jpg

GRAPHIC

Filename: g138848ex99_1s8g1.jpg · Sequence: 21

Binary file (146016 bytes)

Download g138848ex99_1s8g1.jpg

GRAPHIC

Filename: g138848ex99_1s9g1.jpg · Sequence: 22

Binary file (124500 bytes)

Download g138848ex99_1s9g1.jpg

XML — IDEA: XBRL DOCUMENT

XML

Filename: R1.htm · Sequence: 24

v3.26.1

Document and Entity Information

Jun. 01, 2026

Cover [Abstract]

Amendment Flag

false

Entity Central Index Key

0001676725

Document Type

8-K

Document Period End Date

Jun. 01, 2026

Entity Registrant Name

IDEAYA Biosciences, Inc.

Entity Incorporation State Country Code

Entity File Number

001-38915

Entity Tax Identification Number

47-4268251

Entity Address, Address Line One

5000 Shoreline Court

Entity Address, Address Line Two

Suite 300

Entity Address, City or Town

South San Francisco

Entity Address, State or Province

Entity Address, Postal Zip Code

94080

City Area Code

(650)

Local Phone Number

443-6209

Written Communications

false

Soliciting Material

false

Pre Commencement Tender Offer

false

Pre Commencement Issuer Tender Offer

false

Security 12b Title

Common Stock, $0.0001 par value per share

Trading Symbol

IDYA

Security Exchange Name

NASDAQ

Entity Emerging Growth Company

false

- Definition

Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.

+ References

No definition available.

+ Details

Name:

dei_AmendmentFlag

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Area code of city

+ References

No definition available.

+ Details

Name:

dei_CityAreaCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Cover page.

+ References

No definition available.

+ Details

Name:

dei_CoverAbstract

Namespace Prefix:

dei_

Data Type:

xbrli:stringItemType

Balance Type:

Period Type:

duration

- Definition

For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

+ References

No definition available.

+ Details

Name:

dei_DocumentPeriodEndDate

Namespace Prefix:

dei_

Data Type:

xbrli:dateItemType

Balance Type:

Period Type:

duration

- Definition

The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

+ References

No definition available.

+ Details

Name:

dei_DocumentType

Namespace Prefix:

dei_

Data Type:

dei:submissionTypeItemType

Balance Type:

Period Type:

duration

- Definition

Address Line 1 such as Attn, Building Name, Street Name

+ References

No definition available.

+ Details

Name:

dei_EntityAddressAddressLine1

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Address Line 2 such as Street or Suite number

+ References

No definition available.

+ Details

Name:

dei_EntityAddressAddressLine2

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the City or Town

+ References

No definition available.

+ Details

Name:

dei_EntityAddressCityOrTown

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Code for the postal or zip code

+ References

No definition available.

+ Details

Name:

dei_EntityAddressPostalZipCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the state or province.

+ References

No definition available.

+ Details

Name:

dei_EntityAddressStateOrProvince

Namespace Prefix:

dei_

Data Type:

dei:stateOrProvinceItemType

Balance Type:

Period Type:

duration

- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityCentralIndexKey

Namespace Prefix:

dei_

Data Type:

dei:centralIndexKeyItemType

Balance Type:

Period Type:

duration

- Definition

Indicate if registrant meets the emerging growth company criteria.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityEmergingGrowthCompany

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

+ References

No definition available.

+ Details

Name:

dei_EntityFileNumber

Namespace Prefix:

dei_

Data Type:

dei:fileNumberItemType

Balance Type:

Period Type:

duration

- Definition

Two-character EDGAR code representing the state or country of incorporation.

+ References

No definition available.

+ Details

Name:

dei_EntityIncorporationStateCountryCode

Namespace Prefix:

dei_

Data Type:

dei:edgarStateCountryItemType

Balance Type:

Period Type:

duration

- Definition

The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityRegistrantName

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityTaxIdentificationNumber

Namespace Prefix:

dei_

Data Type:

dei:employerIdItemType

Balance Type:

Period Type:

duration

- Definition

Local phone number for entity.

+ References

No definition available.

+ Details

Name:

dei_LocalPhoneNumber

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 13e

-Subsection 4c

+ Details

Name:

dei_PreCommencementIssuerTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14d

-Subsection 2b

+ Details

Name:

dei_PreCommencementTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Title of a 12(b) registered security.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b

+ Details

Name:

dei_Security12bTitle

Namespace Prefix:

dei_

Data Type:

dei:securityTitleItemType

Balance Type:

Period Type:

duration

- Definition

Name of the Exchange on which a security is registered.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection d1-1

+ Details

Name:

dei_SecurityExchangeName

Namespace Prefix:

dei_

Data Type:

dei:edgarExchangeCodeItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14a

-Subsection 12

+ Details

Name:

dei_SolicitingMaterial

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Trading symbol of an instrument as listed on an exchange.

+ References

No definition available.

+ Details

Name:

dei_TradingSymbol

Namespace Prefix:

dei_

Data Type:

dei:tradingSymbolItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Securities Act

-Number 230

-Section 425

+ Details

Name:

dei_WrittenCommunications

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration