Alphamab Oncology  announced that HER2 bispecific antibody Anbenitamab Injection (KN026), independently developed by the Company, and co-developed with JMT-Bio Technology Co., Ltd., a wholly-owned subsidiary of CSPC Pharmaceutical Group Co., Ltd. (stock code: 1093.HK), in combination with Docetaxel for Injection (Albumin-bound) (HB1801), has met the pre-specified primary endpoint of total pathological complete response (tpCR) in a Phase III clinical study (KN026-004) for the  neoadjuvant treatment of HER2-positive early or locally advanced breast cancer (BC). Compared with the current standard of care (trastuzumab plus pertuzumab and docetaxel±carboplatin, i.e., the TCbHP regimen), the Anbenitamab combination therapy significantly improved tpCR, with both statistical and clinical significance.

KN026-004 is the world's first registrational study to demonstrate in a head-to-head Phase III trial that a HER2 bispecific antibody is superior to the combination of trastuzumab and pertuzumab (two monoclonal antibodies), marking a historic breakthrough for bispecific antibodies in the neoadjuvant treatment of breast cancer. Detailed data will be presented at an upcoming international academic conference. The positive results of KN026-004 offer a promising new neoadjuvant option for patients with HER2-positive early breast cancer – one that delivers better efficacy.

Study Design

KN026-004 is a randomized, controlled, open-label, multicenter Phase III study designed to enroll approximately 520 patients with early or locally advanced HER2-positive breast cancer, randomized 1:1 to the experimental arm (Anbenitamab + HB1801 ± carboplatin) or the control arm (trastuzumab + pertuzumab + docetaxel ± carboplatin). The primary endpoint is tpCR assessed by a blinded independent review committee (BIRC).

Key Clinical Advantages

Shorter Regimen: KN026-004 adopts a single-stage, continuous 6-cycle regimen (Anbenitamab + HB1801 ± carboplatin), allowing patients to undergo radical surgery approximately 6 weeks earlier. In contrast, the recently approved trastuzumab deruxtecan (T-DXd, i.e., DS-8201) sequential THP regimen requires 8 cycles – patients first receive 4 cycles of T-DXd followed by 4 cycles of THP, where T-DXd essentially replaces only 4 cycles of dose-dense doxorubicin plus cyclophosphamide (ddAC) used in the traditional regimen. KN026-004 achieves continuous, uninterrupted HER2 signal blockade with a simpler 6-cycle regimen, requiring no drug switching or segmented treatment.

Significant Clinical Value: The bispecific antibody regimen eliminates treatment gaps and avoids efficacy fluctuations that may occur when switching between different drugs in sequential regimens. The partner chemotherapy HB1801 is an albumin-bound formulation of docetaxel that requires no steroid premedication, expected to maintain efficacy while reducing the toxicity burden associated with conventional docetaxel. Anbenitamab is a non-ADC bispecific antibody, thus avoiding serious adverse events unique to ADC drugs such as interstitial lung disease, offering a more manageable safety profile. Additionally, physicians may decide whether to combine carboplatin based on the patient's specific condition.

Full Treatment-Cycle Coverage

In addition to the neoadjuvant Phase III study (KN026-004) that has met its primary endpoint, the adjuvant Phase III study (KN026-007) completed first patient dosing in March 2026 and plans to enroll approximately 1,800 patients with high recurrence risk after surgery.

Domestically developed bispecific antibody Anbenitamab and the innovative chemical drug HB1801 offer significant cost advantages. If approved and subsequently included in the national reimbursement drug list, they are expected to benefit a wider population of HER2-positive breast cancer patients.