Japan-based Daiichi Sankyo Inc. (TYO: 4568) has announced the first patient dosing in a global pivotal Phase II clinical study (S7300-127) assessing the efficacy and safety of its DS7300 (DS7300a), a potential first-in-class antibody drug conjugate (ADC), in patients with extensive small-cell lung cancer (SCLC) in China. DS7300 is an investigational ADC targeting B7-H3 and is designed on Daiichi Sankyo’s proprietary DXd ADC platform.
DS7300: Mechanism and Development
The molecule is composed of a humanized anti-B7-H3 IgG1 monoclonal antibody (mAb) coupled to an exatecan derivative payload, a topoisomerase I inhibitor, through a tetrapeptide-based cleavable linker. DS7300 was initially put into a Phase I/II clinical study in 2019 and filed for clinical trials in China in May 2022, following Bio-Thera Solutions’ BAT8009 as the second of its kind.
Targeting B7-H3 in Cancer Therapy
B7-H3 (B7 homologue 3) is a transmembrane protein belonging to the B7 family and plays a role in tumor growth and immune response. It is often overexpressed in various types of cancer, including lung, head and neck, esophageal, prostate, endometrial, and breast cancers. B7-H3 is associated with disease progression and poor prognosis in many tumor types. Currently, no B7-H3 targeted therapy has been approved to treat any cancer.
Unmet Needs in Small-Cell Lung Cancer
Lung cancer is the second most common cancer globally, with small-cell lung cancer (SCLC) accounting for 15% of lung cancer cases in China, mostly at the extensive stage. The five-year survival rate for these patients is less than 7%, highlighting significant unmet clinical needs. Daiichi Sankyo’s DS7300 aims to address these challenges through its innovative ADC platform.-Fineline Info & Tech
