Biocytogen Announces Clinical Milestone with First Patient Dosed in Phase 1 Trial of IDEAYA’s First-in-Class B7H3/PTK7 Bispecific TOP1 ADC IDE034

Key Terms

b7h3 medical

B7-H3 (also called CD276) is a protein found on the surface of some healthy and cancerous cells that helps regulate the immune system’s response. For investors, it matters because therapies or diagnostics that target B7-H3 aim to unmask cancer cells or deliver drugs directly to them—similar to removing camouflage or attaching a homing beacon—and success can drive significant commercial value and affect clinical and regulatory risk for companies developing these products.

ptk7 medical

PTK7 is a protein found on the surface of many cells that helps guide how cells move, grow and communicate; think of it as a traffic signal or compass for cellular behavior. For investors, PTK7 matters because it can serve as a visible marker on diseased cells and a target for therapies or diagnostic tests, so drugs or tests that bind PTK7 can create commercial opportunities or signal progress in clinical programs.

adc medical

An antibody-drug conjugate (ADC) is a targeted cancer medicine that pairs an antibody that recognizes specific markers on tumor cells with a potent cell-killing drug, connected so the toxic payload is delivered directly to the cancer. For investors, ADCs matter because successful ADCs can improve patient outcomes and reduce side effects compared with traditional chemotherapy, shaping clinical trial success, regulatory approval chances, commercial demand, and a company’s valuation much like a guided missile versus a general bomb.

parg inhibitor medical

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.

dna damage response medical

A DNA damage response is the set of cellular systems that detect and repair breaks or errors in a cell’s genetic material; think of it as a repair crew and alarm system that keeps DNA functioning properly. It matters to investors because drugs that enhance, inhibit, or exploit these repair pathways can change a therapy’s effectiveness, safety, market potential and regulatory risk, affecting the value of biotech and pharmaceutical companies.

pk medical

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.

• IDE034 is a B7H3/PTK7 bispecific TOP1 ADC designed to target tumor cells expressing both B7H3 and PTK7 preferentially, and is being evaluated as monotherapy and in combination with IDEAYA’s PARG inhibitor IDE161.
• IDEAYA has dosed the first patient in its Phase 1 trial of IDE034, initially evaluating safety, tolerability, and PK.
• First dosing triggers a $5 million milestone payment to Biocytogen under the companies’ option and license agreement.

BEIJING--(BUSINESS WIRE)-- Biocytogen Pharmaceuticals (Beijing) Co., Ltd. (Biocytogen, SSE: 688796; HKEX: 02315), a global biotechnology company that drives the research and development of novel antibody-based drugs with innovative technologies, today announced that its partner IDEAYA Biosciences, Inc. (“IDEAYA”; Nasdaq: IDYA) has dosed the first patient in IDEAYA’s Phase 1 dose-escalation/expansion clinical trial of IDE034, an investigational B7H3/PTK7 bispecific TOP1 ADC. Pursuant to the companies’ option and license agreement, first patient dosing triggers a $5 million milestone payment to Biocytogen.

According to IDEAYA, the Phase 1 study is designed to characterize IDE034’s safety profile, tolerability, and PK as a monotherapy, and IDEAYA also intends to evaluate combination regimens with DNA damage response (DDR) -targeting agents such as its oral PARG inhibitor IDE161 as the program advances.

IDE034 is a potential first-in-class bispecific B7H3/PTK7 TOP1 ADC, independently developed by Biocytogen and licensed to IDEAYA in July 2024. IDEAYA has stated that IDE034 is designed to preferentially internalize in tumor cells co-expressing B7H3 and PTK7, supporting selectivity and tolerability, and estimates 30–40% co-expression across several major solid tumors with limited dual expression in normal tissues.

“Reaching first dosing in the IDE034 Phase 1 trial marks an important step in translating this bispecific TOP1 ADC concept into clinical evaluation,” said Dr. Yuelei Shen, President and CEO of Biocytogen. “We appreciate IDEAYA’s strong execution in advancing IDE034 into the clinic and look forward to the readout of initial safety and PK data from the ongoing Phase 1 study.”

About Biocytogen

Biocytogen (SSE: 688796; HKEX: 02315) is a global biotechnology company that drives the research and development of novel antibody-based drugs with innovative technologies. Founded on gene editing technology, Biocytogen has established a dual-engine platform combining a fully human antibody library with an extensive target-humanized mouse model portfolio, enabling a systematic approach to accelerating global drug discovery and development.

Biocytogen has independently developed its proprietary RenMice^® (RenMab^®/ RenLite^®/ RenNano^®/RenTCR™/ RenTCR mimic™) platforms for fully human monoclonal/bispecific/multispecific antibody discovery, bispecific antibody-drug conjugate discovery, hu-VHH discovery, and TCR mimic antibody discovery, and has established a sub-brand, RenSuper™ Biologics, to explore global partnerships for an off-the-shelf library of >1,000,000 fully human antibody sequences against over 1000 targets for worldwide collaboration. As of June 30, 2025, approximately 280 therapeutic antibody and multiple clinical asset co-development/out-licensing/transfer agreements and over 50 target-nominated RenMice^® licensing projects have been established around the globe, including several partnerships with multinational pharmaceutical companies (MNCs). Biocytogen pioneered the generation of drug target knock-in humanized models for preclinical research, and currently provides a few thousand off-the-shelf animal and cell models under the company's sub-brand, BioMice™, along with preclinical pharmacology and gene-editing services for clients worldwide. Headquartered in Beijing, Biocytogen has branches in China (Haimen, Jiangsu, Shanghai), the USA (Boston, San Francisco, San Diego), and Germany (Heidelberg). For more information, please visit https://biocytogen.com.

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Biocytogen Contacts

Antibody assets and platforms: BD-Licensing@biocytogen.com

Media: pr@biocytogen.com.cn

Source: Biocytogen Pharmaceuticals (Beijing) Co., Ltd.