Anbenitamab Regimen Meets Phase 3 End Points in HER2+ Breast Cancer

Results from a phase 3 clinical trial evaluating anbenitamab (KN026; Ennituo) plus docetaxel for injection albumin-bound (HB1801) in patients with HER2-positive breast cancer met the prespecified primary end point of progression-free survival (PFS) assessed by the independent data monitoring committee, according to a press release from the developer, CSPC Pharmaceutical Group Limited.¹

In the phase 3 HEALER or KN026-003 trial (NCT05838066), investigators plan to enroll approximately 880 patients with HER2-positive advanced breast cancer, who will be randomly assigned 1:1 to receive anbenitamab plus HB1801 or trastuzumab (Herceptin), pertuzumab (Perjeta), and docetaxel (THP). The combination significantly prolonged PFS and reduced the risk of disease progression or death compared with THP. A trend toward an overall survival benefit was also observed. Full data from HEALER are expected to be presented at an upcoming international academic conference.

Developers designed anbenitamab injection as a HER2 bispecific antibody. According to the press release, China’s National Medical Products Administration approved anbenitamab in combination with chemotherapy for adults with locally advanced or metastatic HER2-positive gastric or gastroesophageal junction adenocarcinoma who have received 1 prior line of treatment including trastuzumab in May 2026.

Previously, at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, results from the phase 3 Neo-Healer trial (NCT06747338) were presented. In Neo-Healer, 521 patients with early or locally advanced HER2-positive breast cancer were randomly assigned 1:1 to receive anbenitamab (30 mg/kg) plus HB1801 (100 mg/m²) with or without carboplatin (AUC 6) every 3 weeks for 6 cycles or the standard THP regimen with or without carboplatin every 3 weeks for 6 cycles prior to surgery. The primary end point was total pathological complete response (tpCR; ypT0/is ypN0) as assessed by a blinded independent review committee (BIRC). Stratification factors included clinical stage, hormone receptor (HR) status, and planned carboplatin use.²

BIRC-assessed tpCR was significantly higher in the anbenitamab plus HB1801 arm vs the THP arm (62.4% vs 51.2%; absolute difference, 11.4%; 95% CI, 3.19%-19.63%; P = .0036). The benefit was consistent across all prespecified subgroups, including patients with HR-positive or HR-negative disease, early or locally advanced disease, and those with or without planned carboplatin use. Investigator-assessed tpCR also significantly favored the experimental arm (absolute difference, 12.9%; 95% CI, 4.75%-21.14%; P = .0011).

BIRC-assessed breast pathological complete response (bpCR) significantly improved with anbenitamab plus HB1801 vs THP (absolute difference, 9.8%; 95% CI, 1.65%-17.99%; P = .0099), as did investigator-assessed bpCR (absolute difference, 10.6%; 95% CI, 2.45%-18.74%; P = .0057). Investigator-assessed confirmed preoperative overall response rate (ORR) was 94.3% in the anbenitamab arm vs 92.2% in the THP arm.

The safety profiles of the regimens were comparable. Grade 3 or higher treatment-related adverse events occurred in 29.3% of patients in the anbenitamab plus HB1801 arm and 28.3% of those in the THP arm. No treatment-related deaths were reported in either group. Treatment-emergent adverse events leading to discontinuation occurred in 4.9% and 3.5% of patients in the anbenitamab and THP arms, respectively, with the most common events primarily attributable to carboplatin-related toxicities.

References

1.Phase III clinical study of anbenitamab (KN026) in combination with docetaxel for injection (albumin-bound) (HB1801) for first-line treatment of HER2-positive advanced breast cancer meets primary endpoint. News release. CSPC Pharmaceutical Group Limited. June 10, 2026. Accessed June 11, 2026. https://tinyurl.com/4fhvyud3

2.Shao Z-M, Ji P, Liu T, et al. Anbenitamab plus albumin-bound docetaxel ± carboplatin as neoadjuvant therapy in early or locally advanced HER2-positive breast cancer: randomized, phase 3, Neo-Healer trial. J Clin Oncol. 2026;44(suppl17):LBA660.doi:10.12/JCO.2026.44.17_suppl.LBA660