Puxitatug Samrotecan B7-H4 ADC Posts 48% ORR in Relapsed Endometrial Cancer

Puxitatug samrotecan (AZD8205) is a B7-H4–directed topoisomerase I ADC tested in the Phase 1/2a BLUESTAR expansion (NCT05123482) in B7-H4-positive relapsed/metastatic endometrial or ovarian cancer after platinum-based therapy. Activity was highest in endometrial cancer at 2.4 mg/kg Q3W, with ORR 48% (n=50), median DOR 7.1 months, and median PFS 8.1 months; ovarian cancer ORR was lower at 12.1%–24.4% depending on dose. Grade ≥3 TRAEs were dose-associated, including 47.1% in endometrial cancer at 2.4 mg/kg and 75.6% in ovarian cancer at 2.4 mg/kg, driven mainly by cytopenias, while discontinuations were low.