Anbenitamab Raises tpCR in ERBB2-Positive Breast Cancer

Neoadjuvant anbenitamab plus HB1801 produced a significantly higher total pathologic complete response (tpCR) rate than trastuzumab, pertuzumab, and docetaxel in stage II or III ERBB2-positive breast cancer, according to a phase 3 randomized clinical trial published in JAMA Oncology.

Anbenitamab is an ERBB2-biparatopic antibody that induces receptor clustering, while HB1801 is a solvent-free albumin-bound docetaxel. The multicenter, open-label trial enrolled patients at 61 hospitals in China. Investigators randomly assigned 521 participants to 6 neoadjuvant cycles of anbenitamab plus HB1801 or trastuzumab, pertuzumab, and docetaxel; either regimen could include carboplatin.

The primary endpoint, tpCR, was assessed by a blinded independent review committee. tpCR occurred in 164 of 263 patients (62.4%) in the investigational group and 132 of 258 (51.2%) in the control group, an absolute difference of 11.4 percentage points (95% CI, 3.2-19.6; P=0.004). Breast pathologic complete response rates were 65.8% and 55.4%, respectively, while overall response rates were 94.3% and 92.2%.

The tpCR advantage was consistent across subgroups defined by hormone receptor status, disease stage, and carboplatin use. Grade 3 or 4 treatment-related adverse events occurred in 29.3% of the investigational group and 28.3% of controls. Treatment discontinuation due to treatment-related adverse events occurred in 4.9% and 3.5%, respectively; no treatment-related deaths or symptomatic left ventricular systolic dysfunction occurred.

The authors noted that enrollment exclusively in China may limit generalizability. Because both investigational agents were tested together, their individual contributions to the tpCR benefit could not be determined. The optimal adjuvant treatment after anbenitamab-based neoadjuvant therapy also remains unresolved. Investigators said long-term survival follow-up is warranted.

Source: Li J, Liu T, Yu KD, et al. Neoadjuvant anbenitamab and HB1801 in ERBB2-positive breast cancer: a phase 3 randomized clinical trial. JAMA Oncol. Published online September 3, 2026. doi:10.1001/jamaoncol.2026.3329