Merck and Kelun-Biotech revealed Phase 3 breast cancer data for the lead antibody-drug conjugate in their potentially $12 billion partnership.
In a Phase 3 trial for locally recurrent or metastatic triple-negative breast cancer, the anti-TROP2 ADC sacituzumab tirumotecan (previously known as SKB264/MK-2870) reduced patients’ risk of disease progression or death (PFS) by 69% compared with chemotherapy. Additionally, patients’ overall risk of death (OS) was reduced by 47%. Both results were statistically significant.
The median PFS for the active arm was 5.7 months, compared with 2.3 months for those taking chemo. Median OS was not reached in the active arm, and was 9.4 months with chemo.
Sacituzumab tirumotecan, or sac-TMT, is one of three ADCs that Merck and Kelun have in the clinic after signing several collaboration deals dating back to May 2022. They’re also working on four other preclinical ADCs.
Researchers are also testing the ADC in endometrial and lung cancers, among others.
The companies enrolled and randomized 263 patients in the study, which looked at patients in China. Merck is also running a Phase 3 study in the adjuvant setting. The PFS data cutoff was June 21, 2023, while the OS data cutoff was Nov. 30, 2023.
Editor’s note: This article was updated to include information that this study was run in China, and that Merck is running another Phase 3 trial in the adjuvant setting.