Results for the ACE-Breast-02 study were presented at the American Society of Clinical Oncology 2024 on 3 June. This randomised trial, conducted across 85 centres in China, compared Ambrx Biopharma’s antibody-drug conjugate (ADC) ARX788 (anvatabart opadotin), a HER2-targeting antibody conjugated to Amberstatin 269 with a non-cleavable linker, to a combination of lapatinib + capecitabine (LC) in patients with metastatic breast cancer (mBC) previously treated with Herceptin (trastuzumab) and chemotherapy. ARX788 is attempting to enter a crowded field, Enhertu (trastuzumab deruxtecan) is the standard of care in this setting in the US.
But in markets such as China, where access is more limited even though it gained an approval in this setting in February 2023, other options such as Kadcyla (trastuzumab emtansine), or HER family-targeting TKIs such as Jiangsu Hengrui Medicine’s Irene (pyrotinib), and GSK’s Tykerb (lapatinib), are commonly used. In ACE-Breast-02, ARX788 managed to prolong progression-free survival (PFS) compared to LC, with ARX788 having a PFS of 11.33 months (95% confidence interval [CI]: 8.
44, 13.83) and LC having a PFS of 8.25 months (95% CI: 6.
93, 8.71) with a hazard ratio (HR) of 0.64 (95% CI: 0.
49, 0.82). Grade 3 or higher adverse events (AE) occurred in 41.
4% of experimental arm patients and 40% of control arm patients. Comparing these results to those of the EMILIA trial, published in 2012, which resulted in the approval of Kadcyla in mBC, where Kadcy.
