IDEAYA Initiates Phase 1 Combo Trial Targeting DLL3 in Multiple Cancers
Event summary
- IDEAYA Biosciences has begun a Phase 1 clinical trial combining IDE849 (DLL3-targeting ADC) and IDE161 (PARG inhibitor) in patients with DLL3-upregulated solid tumors.
- The trial will evaluate the combination in small cell lung cancer (SCLC), neuroendocrine tumors (NETs), neuroendocrine carcinomas (NECs), and melanoma.
- Preliminary data from IDE849 monotherapy shows multiple partial responses (PRs) in SCLC patients, including 3 out of 4 pre-treated with IMDELLTRA® at 2.4 mg/kg.
- IDE161 is designed to enhance the efficacy of TOP1 ADCs by preventing PARG-mediated DNA repair, leading to accumulation of DNA damage.
- Clinical data updates for both IDE849 monotherapy and the combination with IDE161 are expected in H2 2026.
The big picture
IDEAYA's strategy of combining targeted therapies, particularly ADCs with PARG inhibitors, represents a growing trend in oncology to overcome resistance and improve treatment durability. The focus on DLL3, a target with limited expression in normal tissues, aims to minimize off-target effects. Success here could validate IDEAYA’s synthetic lethality approach and potentially expand its pipeline beyond the initial indications.
What we're watching
- Clinical Efficacy
- The observed PRs in SCLC patients pre-treated with IMDELLTRA® warrant close monitoring; the combination's efficacy will need to significantly exceed existing therapies to drive adoption.
- Regulatory Pathway
- IDEAYA's plans to initiate a registrational study by year-end hinge on the Phase 1 data; a clear regulatory pathway for the combination will be crucial for long-term value.
- Partner Dynamics
- The consistency of IDEAYA's data with that of Jiangsu Hengrui Pharmaceuticals will be a key indicator of collaboration effectiveness and potential future revenue sharing.
Related topics