Clinical progress of B7-H3 targeted antibody drug conjugate ifinatamab deruxtecan for small-cell lung cancer

Small cell lung cancer is an aggressive malignancy with limited treatment options and poor prognosis, particularly at extensive stage. While first-line platinum-etoposide chemotherapy combined with anti-PD-L1 therapy improves survival, most patients relapse, highlighting the need for novel therapies. B7-Homolog3 (B7-H3), an immune checkpoint molecule overexpressed in SCLC, has emerged as a promising therapeutic target. Ifinatamab deruxtecan (I-DXd) is an antibody-drug conjugate targeting B7-H3, delivering a topoisomerase I inhibitor. Early clinical trials (IDeate-PanTumor01 and IDeate-Lung01) have demonstrated encouraging results in pretreated ES-SCLC. In the 12 mg/kg cohort of IDeate-Lung01, I-DXd achieved an objective response rate of 54.8%, median progression-free survival of 5.5 months, and median overall survival of 11.8 months. Notably, it showed intracranial activity with a central nervous system-confirmed response rate of 37.8%. I-DXd is currently being evaluated in the phase III IDeate-Lung02 trial. Its promising efficacy, manageable safety profile, and potential in combination strategies position it as a key candidate for future SCLC treatment.