IDEAYA Biosciences Announces First-Patient-In for Phase 1 Trial of IDE574, a Potential First-In Class Dual Inhibitor of KAT6/7 to Target Multiple Solid Tumor Indications, including Breast, Prostate, CRC, and Lung Cancer

Rhea-AI Summary

IDEAYA (NASDAQ: IDYA) announced first‑patient‑in for a Phase 1 dose‑escalation trial of IDE574, a potential first‑in‑class oral dual inhibitor of KAT6 and KAT7, on April 6, 2026. The trial will evaluate safety, pharmacokinetics, and monotherapy efficacy in solid tumors including breast, prostate, colorectal, and lung cancer.

IDE574 shows single‑digit to low‑teen nanomolar cellular potency, ~350‑to‑2,000x selectivity versus KAT5/KAT8, and superior preclinical monotherapy durability versus KAT6 selective inhibitors; a preclinical profile will be presented at AACR 2026.

Positive

• Phase 1 first‑patient enrolled (IDE574) on April 6, 2026
• Dual KAT6/7 inhibitor with single‑digit to low‑teen nM potency
• Approximately 350–2,000x selectivity versus KAT5 and KAT8
• Preclinical monotherapy efficacy superior to KAT6‑selective inhibitors

Negative

• No clinical safety or efficacy data available yet
• Early‑stage trial; human tolerability and dose limits unknown

News Market Reaction – IDYA

-1.22%

-1.22% Session close to close

In the Apr 6 session, IDYA declined 1.22%, reflecting a mild negative market reaction.

Data tracked by StockTitan Argus on the day of publication.

Market Context

This announcement marks first‑patient‑in for IDE574, a dual KAT6/7 inhibitor entering a Phase 1 tria...

Analysis

This announcement marks first‑patient‑in for IDE574, a dual KAT6/7 inhibitor entering a Phase 1 trial across solid tumors, including breast, prostate, colorectal and lung cancer. It extends IDEAYA’s recent cadence of clinical starts and pivotal enrollment milestones. With historical clinical‑trial headlines averaging about 2.01% moves, investors may monitor future safety, efficacy and combination data, as well as how IDE574 complements existing programs like IDE034, IDE849 and darovasertib within the broader pipeline strategy.

Key Figures

Selectivity window: 350-to-2,000-fold ESR1 mutation prevalence: 10% to 50% Trial phase: Phase 1

3 metrics

Selectivity window 350-to-2,000-fold Selectivity of IDE574 vs KAT5 and KAT8 paralogs

ESR1 mutation prevalence 10% to 50% Breast cancer resistance to endocrine therapy

Trial phase Phase 1 Dose escalation trial of IDE574 in solid tumors

Previous Clinical trial Reports

5 past events · Latest: Mar 30 (Positive)

Same Type Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
Mar 30	FPI combo Phase 1	Positive	+3.3%	First-patient-in for IDE849 plus IDE161 Phase 1 combination in DLL3 tumors.
Mar 9	FPI IDE892 trial	Positive	+5.7%	First-patient-in for IDE892 Phase 1 in MTAP-deleted tumors and pipeline update.
Feb 27	Partner trial milestone	Positive	+2.6%	First dosing in IDE034 Phase 1 trial triggering $5M milestone to Biocytogen.
Feb 25	FPI IDE034 trial	Positive	-1.3%	First-patient-in for IDE034 Phase 1 bispecific TOP1 ADC dose escalation/expansion.
Dec 11	Pivotal trial enrollment	Positive	-0.2%	Completion of targeted full enrollment in darovasertib Phase 2/3 OptimUM-02 trial.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

Clinical-trial headlines for IDYA, especially first-patient-in and pivotal milestones, have generally led to modest positive moves, though occasional small selloffs occur even on positive updates.

Recent Company History

Over the past few months, IDEAYA has repeatedly advanced its pipeline with multiple clinical catalysts. First‑patient‑in updates for IDE034, IDE892, and IDE849 and pivotal enrollment completion for darovasertib (Phase 2/3 OptimUM‑02, 435 patients) all carried positive development tone. Market reactions clustered around low‑single‑digit moves, with three of five clinical‑trial events producing gains between 2.61% and 5.69%, and two showing slight declines, underscoring generally constructive but not euphoric responses to clinical milestones.

Key Terms

lysine acetyltransferase, kat6/7, chromatin remodeling, epigenetic, +4 more

8 terms

lysine acetyltransferase medical

"oral small molecule equipotent dual inhibitor of the lysine acetyltransferase (KAT) 6 and 7 paralogs"

A lysine acetyltransferase is an enzyme that attaches a small chemical tag (an acetyl group) to specific lysine building blocks on proteins, changing how those proteins behave or where they sit inside a cell. Investors care because these enzymes can control gene activity and disease processes, making them important targets for new drugs and diagnostics — like a light switch that a therapy can flip to restore normal function or halt illness.

kat6/7 medical

"dual inhibitor of KAT6/7 with single-digit to low teens nano-molar cellular potency"

KAT6 and KAT7 are proteins that add small chemical tags to other proteins in the cell, especially those that help control whether genes are turned on or off. Think of them as the dimmer switches that modulate gene activity; when they malfunction, it can influence cell growth and disease. Investors watch them because they are targets for new drugs, potential biomarkers for diagnosis or prognosis, and can affect the commercial and regulatory outlook for therapies.

chromatin remodeling medical

"We believe the novel chromatin remodeling mechanism of the KAT6/7 dual inhibitor IDE574"

Chromatin remodeling is the cellular process that changes how tightly DNA is packed inside the nucleus, which controls whether genes are accessible to be turned on or off. For investors, this matters because drugs or diagnostics that target remodeling pathways can alter disease-related gene activity, creating potential therapies, biomarkers, or safety risks; think of it like rearranging books on a shelf so some become easy to reach while others are hidden.

epigenetic medical

"KAT6 and KAT7 are epigenetic modulators of cell identity and lineage commitment"

Epigenetic describes changes that alter how genes are turned on or off without changing the underlying DNA sequence, similar to flipping light switches or adjusting software settings that control a machine. For investors, epigenetic mechanisms matter because they create new targets for drugs, diagnostics, and therapies that can modify disease processes or patient responses, potentially leading to novel products, market opportunities, and long-term revenue streams.

esr1 medical

"Estrogen-receptor 1 mutations (ESR1) is a common acquired resistance mechanism"

ESR1 is a gene that makes the estrogen receptor alpha protein, a cellular “lock” that the hormone estrogen (the “key”) fits into to tell cells how to grow, divide and behave. Mutations or changes in ESR1 can change how cancers—especially breast and other hormone-driven tumors—respond to hormone-blocking drugs, so investors track ESR1-linked tests, drugs and trial results because they directly affect treatment choices, market size and regulatory chances in oncology and women’s health.

cdx medical

"greater monotherapy efficacy and durability than KAT6 selective inhibitors in preclinical CDX and PDX models"

A CDx (companion diagnostic) is a medical test that identifies which patients are likely to benefit from, or be harmed by, a specific prescription drug. Think of it like a key that tells doctors which lock (patient) matches a particular medicine, enabling more precise treatment choices; for investors, CDx tests can be crucial because regulatory approval and commercial uptake of a therapy often depend on the availability and performance of its companion diagnostic, affecting a drug’s market size and revenue timing.

pdx medical

"greater monotherapy efficacy and durability than KAT6 selective inhibitors in preclinical CDX and PDX models"

Patient-derived xenograft (PDX) is a lab model made by implanting a human patient's tumor into a live animal, typically a mouse, so the cancer grows in a setting that closely mimics human disease. For investors, PDX studies act like a realistic prototype test: they provide early evidence about whether an experimental cancer therapy might work in people, helping to reduce clinical risk and informing a company's development outlook and valuation.

pharmacokinetics medical

"evaluate safety, efficacy and pharmacokinetics of IDE574 as a monotherapy in the Phase 1 dose escalation trial"

Pharmacokinetics is the study of how a substance, such as a drug or chemical, moves through and is processed by the body over time. It tracks how it is absorbed, distributed, broken down, and eventually eliminated. For investors, understanding pharmacokinetics helps gauge the effectiveness, safety, and potential risks of new medications or treatments, which can influence a company’s success and valuation in the healthcare industry.

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• Potential first-in-class and selective equipotent dual inhibitor of KAT6/7 with single-digit to low teens nano-molar cellular potency in target engagement assays against KAT6 and KAT7, and ~350-to-2,000-fold selectivity over the KAT5 and KAT8 paralogs
• KAT6/7 dual inhibitor demonstrates greater monotherapy efficacy and durability than KAT6 selective inhibitors in preclinical CDX and PDX models
• Multiple combination opportunities with IDE574 and IDEAYA's proprietary pipeline
• Potential first-in-class and best-in-class preclinical profile will be presented at AACR 2026

SOUTH SAN FRANCISCO, Calif., April 6, 2026 /PRNewswire/ -- IDEAYA Biosciences, Inc. (NASDAQ: IDYA), a leading precision medicine oncology company, today announced that the first patient has been enrolled in its Phase 1 dose escalation trial evaluating IDE574, a potential first-in-class oral small molecule equipotent dual inhibitor of the lysine acetyltransferase (KAT) 6 and 7 paralogs, both of which have been shown to support cancer cell survival.  The company is planning to evaluate safety, efficacy and pharmacokinetics of IDE574 as a monotherapy in the Phase 1 dose escalation trial in solid tumor patients, including breast, prostate, colorectal, and lung cancer. 

"Targeting mechanisms of resistance and tumor heterogeneity in cancer are core strategies of our R&D efforts, and we are excited to advance IDE574 in the clinic to evaluate its potential as a monotherapy agent to drive deeper, more durable antitumor responses for patients versus historical clinical data published with KAT6-selective agents," said Michael White, Ph.D., Chief Scientific Officer of IDEAYA Biosciences. "We are thrilled to advance another potential first-in-class agent into the clinic that targets large solid tumor indications of high unmet need, including breast, prostate, CRC, and lung cancer.  We believe the novel chromatin remodeling mechanism of the KAT6/7 dual inhibitor IDE574, has the potential for monotherapy efficacy and to treat breast cancer patient's refractory to hormone-based therapy due to ESR1 mutations, and to evaluate rational combinations with assets in the IDEAYA pipeline," said Yujiro S. Hata, President and Chief Executive Officer, IDEAYA Biosciences.

IDE574 is a selective, equipotent dual inhibitor of both KAT6 and KAT7 with single-digit to low-teen nanomolar cellular potency in target engagement assays, which spares other structurally similar KAT paralogs with approximately a 350-to-2,000-fold selectivity windows versus KAT5 and KAT8, both of which are required for normal cell function.  KAT6 and KAT7 are epigenetic modulators of cell identity and lineage commitment programs that are corrupted by oncogenic transformation.  Estrogen-receptor 1 mutations (ESR1) is a common acquired resistance mechanism to endocrine based therapy in breast cancer with prevalence from 10 to 50% (Fuqua, et al., Cancer, July 2019; Zundelevich, et al., Breast Cancer Research, February 2020) highlighting the unmet need for alternative drug mechanisms, such as KAT6/7.  IDE574 has shown robust and durable monotherapy anti-tumor activity, superior to KAT6 inhibition alone, in preclinical tumor models with 8p11 amplifications and ESR1 mutations, as well as in selected indications dependent upon lineage-specific transcription factor activity.

About IDEAYA Biosciences

IDEAYA is a precision medicine oncology company committed to the discovery, development, and commercialization of transformative therapies for cancer.  Our approach integrates expertise in small-molecule drug discovery, structural biology and bioinformatics with robust internal capabilities in identifying and validating translational biomarkers to develop tailored, potentially first-in-class targeted therapies aligned to the genetic drivers of disease.  We have built a deep pipeline of product candidates focused on synthetic lethality and antibody-drug conjugates, or ADCs, for molecularly defined solid tumor indications.  Our mission is to bring forth the next wave of precision oncology therapies that are more selective, more effective, and deeply personalized with the goal of altering the course of disease and improving clinical outcomes for patients with cancer.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, including, but not limited to, statements regarding the potential therapeutic benefits, safety, tolerability, efficacy, pharmacokinetics and clinical development of IDE574; the potential of IDE574 as a first-in-class or best-in-class therapy; the expected design, timing, and results of the Company's Phase 1 clinical trial; the potential for IDE574 to demonstrate monotherapy activity or durability of response; the potential to address resistance mechanisms, including ESR1 mutations; the applicability of IDE574 across multiple solid tumor indications; and the potential for combination strategies with IDEAYA's pipeline.  Such forward-looking statements are based on management's current expectations, assumptions and beliefs and involve substantial risks and uncertainties that could cause actual results, including, but not limited to, those related to IDEAYA's clinical programs, commercial activities, and performance and/or achievements, to differ significantly and/or materially 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 the process of designing and conducting preclinical and clinical trials, enrollment rates, safety outcomes, efficacy results, regulatory interactions and decisions, and the ability to translate preclinical findings into clinical benefit, manufacturing and supply risks, competition, changes in standard of care, the timing and success of commercialization efforts, the outcome of collaborations and licensing arrangements, IDEAYA's ability to successfully establish, protect and defend its intellectual property, and other matters that could affect the sufficiency of financial resources to fund operations. IDEAYA undertakes no obligation to update or revise any forward-looking statements.  A further description of 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, are in IDEAYA's filings with the Securities and Exchange Commission, including IDEAYA's most recent Annual Report on Form 10-K  and any current and periodic reports filed with the U.S. Securities and Exchange Commission.

Investor and Media Contact
IDEAYA Biosciences
Joshua Bleharski, Ph.D.
Chief Financial Officer  
investor@ideayabio.com

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SOURCE IDEAYA Biosciences, Inc.

FAQ

What is IDEAYA announcing about IDE574 and the Phase 1 trial (IDYA)?

IDEAYA announced first‑patient‑in for a Phase 1 dose‑escalation trial of IDE574 to evaluate safety, pharmacokinetics, and monotherapy efficacy. According to the company, the study targets solid tumors including breast, prostate, colorectal, and lung cancer.

How potent and selective is IDE574 reported by IDEAYA (IDYA)?

IDEAYA reports IDE574 has single‑digit to low‑teen nanomolar cellular potency and is equipotent against KAT6 and KAT7. According to the company, it shows ~350‑to‑2,000x selectivity against KAT5 and KAT8 paralogs.

Which cancer types will IDEAYA evaluate IDE574 in the Phase 1 trial (IDYA)?

The Phase 1 dose‑escalation will enroll patients with solid tumors including breast, prostate, colorectal, and lung cancer. According to the company, the study will assess monotherapy safety, pharmacokinetics, and preliminary efficacy in these indications.

What preclinical efficacy does IDEAYA claim for IDE574 (IDYA)?

IDEAYA reports IDE574 showed robust, durable monotherapy antitumor activity and outperformed KAT6‑selective inhibitors in preclinical CDX and PDX models. According to the company, benefits were seen in models with 8p11 amplifications and ESR1 mutations.

Will IDEAYA present IDE574 data publicly and when (IDYA)?

Yes. IDEAYA plans to present the preclinical profile of IDE574 at AACR 2026. According to the company, the presentation will cover potency, selectivity, and comparative preclinical efficacy versus KAT6 selective agents.

What are the near‑term risks for investors in IDEAYA's IDE574 program (IDYA)?

The primary near‑term risks are lack of human safety and efficacy data and early‑stage dose‑finding uncertainty. According to the company, IDE574 is now in Phase 1, so clinical tolerability and therapeutic window remain to be determined.