XMT-1660 (Emi-Le) received a new Fast Track designation for advanced or metastatic HER2-low or HER2-negative breast cancer, including triple-negative breast cancer (TNBC)

The World Health Organization approved “emiltatug ledadotin” (Emi-Le) as the international non-proprietary name for XMT-1660

The designation focuses on patients who previously received a topoisomerase-1 inhibitor ADC, with HR-positive patients requiring prior endocrine therapy or being ineligible for it

Initial data from the Phase 1 clinical trial of XMT-1660 demonstrated that the treatment was well tolerated, with no Grade 4 or 5 treatment-related adverse events, and common side effects being mild and reversible, such as AST increases, proteinuria, nausea, and fatigue

Confirmed ORR was 23% in patients with B7-H4 high tumors, including TNBC patients previously treated with topo-1 ADCs, indicating promising clinical activity in addressing high unmet needs in oncology