Multicenter phase 3 trial of anbenitamab plus HB1801 versus THP for HER2-positive advanced breast cancer

The combination of docetaxel, trastuzumab, and pertuzumab (THP) is an established first-line therapy for patients with HER2-positive advanced breast cancer. The multicenter phase 3 HEALER trial in China compared the combination of anbenitamab (HER2-targeted bispecific antibody) plus albumin-bound docetaxel (HB1801) versus THP for these patients. Patients were randomized 1:1 to receive either anbenitamab plus HB1801 (n=445) or THP (n=440). The primary endpoint was progression-free survival (PFS), as assessed by blinded independent central review. At the prespecified interim analysis with a median follow-up of 21.0 months, the estimated 24-months PFS rate was significantly higher with anbenitamab plus HB1801 than with THP (58.5% versus 34.4%; HR 0.46; p<0.001). The percentage of patients with an objective response was 87.6% in the anbenitamab plus HB1801 group and 73.4% in the THP group. Adverse events of grade 3 or higher occurred in 45.9% of patients in the anbenitamab plus HB1801 group and 34.4% of patients in the THP group. Adverse events leading to death occurred in two patients in each group. The authors conclude that anbenitamab plus HB1801 led to significantly higher PFS rate than THP among patients with HER2-positive advanced breast cancer.