China-based Biokin has reported positive Phase II data for its first-in-class EGFR×HER3 bispecific antibody-drug conjugate (ADC), izalontamab brengitecan (BL-B01D1), in combination with the PD-1 inhibitor serplulimab for the first-line treatment of extensive-stage small cell lung cancer (ES-SCLC). The data, selected for presentation at the 2026 European Lung Cancer Congress (ELCC), represent the first results for an ADC combined with a PD-1 inhibitor in this setting. The combination achieved an overall response rate (ORR) of 88.3% and a median progression-free survival (mPFS) of 8.2 months in the overall study population.
The most common treatment-related adverse events were haematologic, including anaemia, thrombocytopoenia and leukopoenia, which were clinically manageable. The discontinuation rate due to adverse events was low at 7.3%. Based on the safety and efficacy profile, the 2.5 mg/kg dose administered on days 1 and 8 of a 21-day cycle has been selected for further development in China.

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