IDEAYA Biosciences Announces First-Patient-In for Phase 1 Trial of IDE034, a Potential First-In-Class B7H3/PTK7 Bispecific TOP1 ADC

Rhea-AI Summary

IDEAYA Biosciences (NASDAQ: IDYA) announced first‑patient‑in for a Phase 1 dose escalation/expansion trial of IDE034, a B7H3/PTK7 bispecific TOP1 ADC intended for monotherapy and combinations with DDR agents such as IDE161. Dosing of the first patient triggers a $5.0 million milestone payment to Biocytogen.

IDE034 is designed to internalize only when both antigens are co‑expressed, estimated at ~30–40% in select solid tumors, and has shown preclinical monotherapy activity and synergy with IDE161.

Positive

• First patient dosed in Phase 1 IDE034 trial
• $5.0 million milestone payment triggered to Biocytogen
• IDE034 targets B7H3/PTK7 co-expression (~30–40% in select solid tumors)

Negative

• IDE034 is Phase 1, so clinical efficacy and safety remain unproven

Key Figures

Milestone payment: $5 million Trial phase: Phase 1 Target co-expression rate: 30-40% +5 more

8 metrics

Milestone payment $5 million Payment from IDEAYA to Biocytogen on first dosing of IDE034

Trial phase Phase 1 Dose escalation/expansion study for IDE034

Target co-expression rate 30-40% Estimated B7H3/PTK7 co-expression in certain large solid tumors

Cash & securities $1.05 billion Cash, cash equivalents and marketable securities as of Dec 31, 2025

Darovasertib upfront $210.0 million Upfront payment from Servier for ex‑US darovasertib rights

Darovasertib milestones $320.0 million Potential additional milestones from Servier license

2025 collaboration revenue $218.7 million Full-year 2025 collaboration revenue reported in 8-K

2025 R&D expenses $314.7 million Full-year 2025 research and development expenses

Market Reality Check

Price: $32.07 Vol: Volume 730,111 is below t...

normal vol

$32.07 Last Close

Volume Volume 730,111 is below the 20-day average of 856,369 (relative volume 0.85). normal

Technical Trading above the 200-day MA, with price at $32.07 versus MA(200) of $27.72.

Peers on Argus

IDYA dipped -0.12% while peers were mixed: DNLI +2.73%, GLPG -3.83%, BLTE -0.98%...

IDYA dipped -0.12% while peers were mixed: DNLI +2.73%, GLPG -3.83%, BLTE -0.98%, FOLD +0.07%, TVTX +0.19%, suggesting a stock-specific response to the IDE034 Phase 1 update.

Previous Clinical trial Reports

5 past events · Latest: Dec 11 (Positive)

Same Type Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Dec 11	Pivotal trial enrollment	Positive	-0.2%	Completed full enrollment in Phase 2/3 OptimUM-02 darovasertib trial.
Oct 20	Phase 2 efficacy data	Positive	+4.3%	Positive Phase 2 neoadjuvant darovasertib data in primary uveal melanoma.
Oct 20	Survival data update	Positive	+4.3%	Phase 1/2 darovasertib plus crizotinib showed favorable OS, PFS and ORR.
Sep 08	Combination trial data	Positive	-13.9%	Positive Phase 1/2 data for IDE397 plus Trodelvy in MTAP‑deletion UC.
Sep 08	Interim Phase 2 data	Positive	-13.9%	Positive interim Phase 2 darovasertib data in primary uveal melanoma.

Pattern Detected

Clinical updates often show mixed reactions, with several positive data releases followed by negative price moves.

Recent Company History

Recent clinical news for IDEAYA has centered on darovasertib and MTAP-pathway programs, with multiple positive Phase 1/2 and Phase 2 data readouts and completion of enrollment in the pivotal OptimUM-02 trial. Market reactions have been inconsistent: some strong efficacy updates saw declines of about -13.88%, while other positive melanoma data produced gains of about +4.27%. Today’s IDE034 first‑patient‑in milestone adds a new ADC/DDR asset to this evolving clinical portfolio.

Historical Comparison

-3.9% avg move · In the past year, 5 clinical‑trial headlines for IDYA averaged a -3.89% move, with more divergences ...

clinical trial

-3.9%

Average Historical Move clinical trial

In the past year, 5 clinical‑trial headlines for IDYA averaged a -3.89% move, with more divergences than alignments, underscoring volatile reactions to trial news.

Clinical updates have progressed from darovasertib Phase 1/2 and Phase 2 data through pivotal OptimUM-02 enrollment and IDE397 combinations; IDE034’s Phase 1 start extends this trajectory into bispecific TOP1 ADC/DDR combinations.

Market Pulse Summary

This announcement marks first‑patient‑in for IDE034, a B7H3/PTK7 bispecific TOP1 ADC with planned mo...

Analysis

This announcement marks first‑patient‑in for IDE034, a B7H3/PTK7 bispecific TOP1 ADC with planned monotherapy and DDR-pathway combinations, including IDE161. It builds on prior clinical progress in darovasertib and IDE397 while extending IDEAYA’s ADC/DDR strategy. With $1.05 billion in cash and securities and significant 2025 collaboration revenue of $218.7 million, the company has resources to support this new program. Key metrics to watch include IDE034 safety, tolerability, pharmacokinetics, and eventual efficacy signals as the Phase 1 trial matures.

Key Terms

phase 1, dose escalation, pk, top1 adc, +3 more

7 terms

phase 1 clinical

"first patient has been enrolled in its Phase 1 dose escalation/expansion trial"

Phase 1 is the first stage of testing a new drug or medical treatment in people, focused primarily on safety, how the body handles the product, and finding a tolerated dose. Think of it as a short, tightly controlled experiment with a small group to check for dangerous side effects before wider testing; for investors it is an early milestone that reduces some uncertainty but still carries high risk and potential for both big value changes and setbacks.

dose escalation clinical

"Phase 1 dose escalation/expansion trial evaluating IDE034"

Dose escalation is the process of gradually increasing the amount of a treatment or substance over time. In finance, it can refer to slowly raising investments or commitments to manage risk and assess performance. For investors, understanding dose escalation helps gauge how companies or strategies adjust their approaches, which can impact future growth or stability.

pk medical

"to evaluate safety, tolerability and PK of IDE034 as a monotherapy"

Pharmacokinetics (PK) describes how a drug moves through the body—how quickly it is absorbed, how it spreads to tissues, how the body breaks it down, and how it is eliminated. For investors, PK data help predict whether a medicine can reach effective levels without causing harm, how often it must be dosed, and whether drug interactions or patient differences could affect commercial success; think of it as the drug’s travel and timing profile inside the body.

top1 adc medical

"bispecific TOP1 ADC designed to be internalized only when its target antigens"

A TOP1 ADC is an antibody-drug conjugate that uses an antibody to deliver a topoisomerase I inhibitor — a drug that blocks a cancer cell’s DNA repair machinery — directly to tumor cells. For investors, it signals a targeted cancer therapy approach that can increase effectiveness and reduce side effects compared with standard chemo, affecting clinical risk, commercial potential, and valuation like a precision-guided weapon versus a spray-and-pray treatment.

parg inhibitor medical

"plans to test combinations with agents that target the DNA damage response (DDR) pathway, such as their proprietary PARG inhibitor, IDE161"

A PARG inhibitor is a drug that blocks the enzyme poly(ADP‑ribose) glycohydrolase (PARG), which normally helps cells remove chemical tags used to signal and repair DNA damage. By stopping that cleanup crew, the drug can make damaged cells—often cancer cells—less able to fix themselves and more likely to die when exposed to chemotherapy or other treatments; for investors, successful PARG inhibitors can meaningfully raise a developer’s commercial and clinical value but carry high scientific and regulatory risk.

bispecific medical

"a B7H3/PTK7 bispecific ADC that has demonstrated promising signs of efficacy"

A bispecific molecule is a therapeutic designed to bind two different biological targets at once — imagine a two-headed key that fits two locks simultaneously. For investors, bispecific therapies matter because that dual-action can make a treatment more effective or selective, potentially improving clinical results, altering safety profiles, and creating a stronger commercial edge; those factors directly affect development risk, regulatory chances, and future revenue prospects.

monotherapy medical

"has demonstrated promising signs of efficacy as a monotherapy and synergy in combination"

Monotherapy is a treatment approach that uses only one type of medicine or therapy to address a condition, instead of combining multiple options. For investors, understanding monotherapy matters because it can influence a company's development strategy, risk profile, and potential market size, especially if the single-treatment approach proves effective or faces limitations compared to combination therapies.

AI-generated analysis. Not financial advice.

• Phase 1 dose escalation trial to determine safety, tolerability and PK of IDE034
• Potential as a monotherapy and in combination with proprietary PARG inhibitor, IDE161
• B7H3/PTK7 co-expressed in 30-40% of multiple solid tumor types, including lung, breast, ovarian and colorectal cancers

SOUTH SAN FRANCISCO, Calif., Feb. 25, 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/expansion trial evaluating IDE034, an investigational PTK7/B7H3 bispecific TOP1 ADC. The company is planning to evaluate safety, tolerability and PK of IDE034 as a monotherapy in the Phase 1 trial, and also plans to test combinations with agents that target the DNA damage response (DDR) pathway, such as their proprietary PARG inhibitor, IDE161. Dosing of the first patient with IDE034 triggers a $5 million milestone payment from IDEAYA to Biocytogen, pursuant to the Option and License Agreement between the companies.

"This is an important milestone for IDE034 as well as our broader ADC/DDR portfolio focused on exploring combinations of highly selective TOP1 ADCs with agents targeting the DDR pathway.  We are excited to begin dosing patients with IDE034, a B7H3/PTK7 bispecific ADC that has demonstrated promising signs of efficacy as a monotherapy and synergy in combination with IDE161 across several preclinical tumor cell models. IDE034 is our second proprietary TOP1 ADC, building on the progress we have made with IDE849, our DLL3 TOP1 ADC currently in Phase 1 for SCLC and NEC, and represents another potentially first-in-class therapy for cancer patients in need of new and improved treatment options," said Yujiro S. Hata, President and Chief Executive Officer of IDEAYA Biosciences.

IDE034 is a potentially first-in-class B7H3/PTK7 bispecific TOP 1 ADC designed to be internalized only when its target antigens are co-expressed on the same tumor cell, which may enhance its selectivity and tolerability profile relative to monovalent antibody formats. IDEAYA estimates that B7H3/PTK7 are co-expressed in approximately 30-40% of certain large solid tumor types, including lung, breast, ovarian and colorectal cancers, while exhibiting minimal dual antigen expression in normal tissue. In preclinical tumor models, IDE034 has also demonstrated compelling combination potential with IDE161, the company's oral PARG inhibitor, that suggests these mechanisms may synergize to enhance the efficacy and durability of TOP1 ADCs. 

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, including, but not limited to, statements regarding the clinical development, potential safety, tolerability, pharmacokinetic profile, efficacy and therapeutic potential of IDE034, both as a monotherapy and in combination with IDEAYA's proprietary PARG inhibitor, IDE161; the design, conduct, timing and outcomes of the Phase 1 clinical trial of IDE034; the potential benefits of IDEAYA's ADC/DDR portfolio and combination strategies; and the prevalence of B7H3/PTK7 co-expression in certain tumor types. 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 preclinical and 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

View original content to download multimedia:https://www.prnewswire.com/news-releases/ideaya-biosciences-announces-first-patient-in-for-phase-1-trial-of-ide034-a-potential-first-in-class-b7h3ptk7-bispecific-top1-adc-302696480.html

SOURCE IDEAYA Biosciences, Inc.

FAQ

What does IDEAYA announce about IDE034 first‑patient‑in (IDYA) on Feb 25, 2026?

IDEAYA reports it has dosed the first patient in the Phase 1 IDE034 trial, initiating clinical evaluation. According to IDEAYA, dosing also triggers a $5.0 million milestone payment to Biocytogen under the license agreement.

What is IDE034 and which tumors might IDYA target with this ADC?

IDE034 is a B7H3/PTK7 bispecific TOP1 antibody‑drug conjugate designed to internalize when both antigens are co‑expressed. According to IDEAYA, co‑expression is estimated in about 30–40% of lung, breast, ovarian and colorectal tumors.

Will IDEAYA test IDE034 in combination with other agents (IDYA)?

Yes, IDEAYA plans to evaluate IDE034 as monotherapy and in combination with DDR agents, including its oral PARG inhibitor IDE161. According to IDEAYA, preclinical models showed synergy between IDE034 and IDE161.

Does the IDE034 first‑patient‑in create any immediate financial obligations for IDEAYA (IDYA)?

Dosing the first patient triggered a contractual milestone payment of $5.0 million to Biocytogen. According to IDEAYA, this payment is payable under the existing option and license agreement between the companies.

How selective is IDE034 expected to be for tumor cells versus normal tissue (IDYA)?

IDE034 is engineered to internalize only when both B7H3 and PTK7 are co‑expressed, aiming to enhance selectivity. According to IDEAYA, dual antigen expression in normal tissues is expected to be minimal based on preclinical profiling.