IDE034: First Patient Dosed in Phase 1 Trial of Novel Bispecific ADC for Solid Tumors

Beijing, China – February 28, 2026 – Biocytogen Pharmaceuticals (Beijing) Co., Ltd. (Biocytogen, SSE: 688796; HKEX: 02315) today announced that its partner, IDEAYA Biosciences, Inc. (Nasdaq: IDYA), has dosed the first patient in a Phase 1 clinical trial evaluating IDE034, an investigational B7H3/PTK7 bispecific TOP1 antibody-drug conjugate (ADC). The milestone triggers a $5 million payment to Biocytogen, as per their licensing agreement.

What is IDE034?

IDE034 is a potential first-in-class bispecific ADC, initially developed by Biocytogen and licensed to IDEAYA in July 2024. It is designed to target both B7H3 and PTK7 proteins, which are frequently co-expressed in various solid tumors. According to IDEAYA, the ADC is engineered to selectively internalize into tumor cells expressing both B7H3 and PTK7, potentially enhancing efficacy and minimizing off-target effects. The drug utilizes a TOP1 payload, a class of chemotherapy agents that disrupt DNA replication.

Phase 1 Trial Design

The Phase 1 trial is designed to assess the safety, tolerability, and pharmacokinetics (PK) of IDE034 when administered as a monotherapy. Researchers also plan to evaluate the combination of IDE034 with IDE161, IDEAYA’s proprietary PARG inhibitor, which targets the DNA damage response (DDR) pathway. This combination strategy aims to enhance the anti-tumor activity of IDE034 by disrupting the cancer cell’s ability to repair DNA damage.

Tumor Types Under Investigation

The trial will initially enroll patients with solid tumors known to express B7H3 and PTK7, including lung, colorectal, head and neck, and ovarian/gynecological cancers. IDEAYA estimates that 30-40% of these tumor types co-express B7H3 and PTK7, with limited expression in normal tissues, suggesting a potential for targeted therapy.

Biocytogen’s Role and Technology

Biocytogen’s contribution to IDE034 stems from its RenLite® platform and proprietary linker-payload technologies, which are crucial for the discovery and optimization of bispecific ADCs. The company’s RenMice® platforms enable the generation of fully human antibodies and humanized mouse models, accelerating drug discovery and development. Biocytogen has established numerous collaborations with pharmaceutical companies worldwide, licensing its technologies and preclinical models.

Statements from Leadership

“The administration of the first dose in the Phase 1 trial of IDE034 marks an important milestone in translating this TOP1 bispecific ADC concept into clinical evaluation,” said Dr. Yuelei Shen, President and CEO of Biocytogen. “We appreciate IDEAYA’s strong involvement in advancing IDE034 to the clinical phase and look forward to the results of the initial safety and pharmacokinetic data from the ongoing Phase 1 study.”

Looking Ahead

The initiation of the Phase 1 trial represents a significant step forward in the development of IDE034 and the broader field of bispecific ADCs. Researchers will closely monitor the trial’s progress, evaluating the safety, tolerability, and potential efficacy of this novel therapeutic approach for patients with advanced solid tumors. Initial data from the Phase 1 study are anticipated in the coming months.