Multicenter phase 2-3 trial of disitamab vedotin for HER2-positive breast cancer with liver metastases: phase 3 results

Patients with HER2-positive advanced breast cancer with liver metastases (BCLM) have a poor prognosis. The multicenter phase 2-3 RC48-C006 trial in China evaluated disitamab vedotin (DV) versus lapatinib plus capecitabine (L+C) in patients with HER2-positive BCLM who were previously treated with trastuzumab and taxanes. Phase 3 results have now been published. A total of 104 patients were randomized 1:1 to receive DV (n=53) or L+C (n=51). Progression-free survival assessed by the blinded independent reivew committee (PFS-BIRC) was significantly improved with DV versus L+C (median 9.9 versus 4.9 months; HR 0.56; p=0.01), meeting the prespecified primary endpoint. Investigator-assessed PFS was consistent with the BIRC assessment. Prespecified subgroup analyses consistently favored DV. Incidences of grade ≥ 3 treatment-related adverse events were similar with DV versus L+C (37.7% versus 36.0%). The authors conclude that these findings support DV as a treatment option for HER2-positive BCLM following trastuzumab and taxane therapy.