IDEAYA Biosciences (NASDAQ:IDYA), a precision medicine oncology company, announced on April 9, 2026, that it has entered into a clinical collaboration agreement with AstraZeneca (NASDAQ:AZN) to study a potential first-in-class combination treatment for extensive-stage small cell lung cancer (SCLC).
The partnership will evaluate the efficacy and safety of IDEAYA’s IDE849—an investigational DLL3-targeted TOP1 antibody-drug conjugate (ADC)—in combination with AstraZeneca’s PD-L1 inhibitor, Imfinzi® (durvalumab).
Under the terms of the agreement, IDEAYA will serve as the sponsor for the clinical combination study, while AstraZeneca will provide the supply of Imfinzi®.
The collaboration focuses on a significant area of unmet medical need.
Delta-like ligand 3 (DLL3) is a protein frequently upregulated in SCLC and other neuroendocrine-related solid tumors, yet it shows limited expression in healthy tissues.
This distinct profile makes DLL3 a highly promising target for ADC therapies, which are designed to deliver potent cytotoxic payloads directly to malignant cells while sparing normal tissue.
IDEAYA is currently advancing a global Phase 1 clinical trial for IDE849 as a monotherapy.
The trial is enrolling patients across North America, Europe, Australia, South America, and Asia.
In addition to SCLC, the study is targeting other DLL3-upregulated indications, including neuroendocrine carcinomas (NECs), neuroendocrine tumors (NETs), and melanoma.
The scientific rationale for the combination lies in the ability of ADCs to induce "immunogenic cell death."
By using IDE849 to release a TOP1 inhibitor payload directly into the tumor, the treatment may prime the tumor microenvironment, potentially making it more responsive to the immune-boosting effects of Imfinzi®.