Alphamab Oncology Announces the First Patient Dosed in a Phase III Clinical Study of Anbenitamab (KN026) Combined with HB1801 and Chemotherapy as Adjuvant Treatment of Breast Cancer

SUZHOU, China, March 24, 2026 /PRNewswire/ -- Alphamab Oncology (stock code: 9966.HK) today announced that the first patient has been dosed in the Phase III clinical study (KN026-007) of HER2 bispecific antibody Anbenitamab (KN026) in combination with albumin-bound docetaxel (HB1801) and chemotherapy as adjuvant treatment for HER2-positive breast cancer (BC). Anbenitamab (KN026) is 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).

Breast cancer is the most common malignant tumor among women in China, with the HER2-positive subtype accounting for approximately 20% to 30% of all cases. Although trastuzumab (with or without pertuzumab) combined with chemotherapy has significantly reduced the risk of recurrence, subgroup analyses from multiple clinical studies indicate that patients with HER2-positive BC who are lymph node-positive, particularly those with four or more positive lymph nodes, continue to face a high risk of recurrence. Compared with regimens containing trastuzumab alone, dual-targeted therapy combined with chemotherapy as adjuvant treatment for HER2-positive BC can further reduce the risk of recurrence, with the most pronounced benefit observed in lymph node-positive patients. Accordingly, the exploration of more effective adjuvant treatment strategies to improve long-term outcomes for this patient population is of significant clinical importance.

KN026-007 is a randomized, controlled, open-label, multicenter Phase III clinical study, which is expected to enroll approximately 1,800 patients with resectable HER2-positive BC who have histologically confirmed involvement of four or more regional lymph nodes following surgery. Eligible patients will be randomized in a 1:1 ratio, aiming to compare the efficacy and safety of Anbenitamab in combination with HB1801 and chemotherapy versus trastuzumab plus pertuzumab in combination with chemotherapy as adjuvant treatment. The primary endpoint of the study is investigator-assessed invasive disease-free survival (iDFS) . Secondary endpoints include disease-free survival (DFS), recurrence-free interval (RFI), distant recurrence-free interval (DRFI), overall survival (OS), safety, pharmacokinetics, and immunogenicity.

About Anbenitamab (KN026)

Anbenitamab (KN026) is an anti-HER2 bispecific antibody independently developed by Alphamab Oncology using the proprietary Fc-based heterodimer bispecific platform technology called CRIB (Charge Repulsion Induced Bispecific). Anbenitamab can simultaneously bind two non-overlapping epitopes of HER2, resulting in HER2 signal blockade. Through antibody-induced receptor clustering, it enhances ADCC and CDC effects while promoting the down-regulation of HER2 receptors on the cell surface.

In September 2025, the first New Drug Application (NDA) for anbenitamab injection has been accepted by the National Medical Products Administration (NMPA) for the treatment of HER2-positive gastric cancer (GC). Currently, several pivotal clinical trials of KN026 for second-line or above HER2-positive GC/gastroesophageal junction cancer (GEJ), first-line HER2-positive breast cancer (BC), neoadjuvant treatment of HER2-positive BC are being conducted.

Anbenitamab has been granted Orphan Drug Designation by the U.S. Food and Drug Administration (FDA) for the treatment of HER2-positive or low expressing GC; it has been granted Breakthrough Therapy Designation by NMPA for the treatment of patients with HER2-positive GC/GEJ who have failed first-line standard treatment.

In August 2021, the Company entered an agreement with JMT-Bio Technology Co., Ltd. ("JMT-Bio"), a wholly-owned subsidiary of CSPC Pharmaceutical Group Co., Ltd. ("CSPC") (stock code: 1093.HK), for the development and commercialization of KN026 in Mainland China. JMT-Bio was granted exclusive license rights of KN026 for the development and commercialization in the indications of BC an GC/GEJ in Mainland China (excluding Hong Kong, Macau and Taiwan).

About Docetaxel (Albumin-Bound)

Docetaxel (Albumin-Bound) for Injection (HB1801) is a product developed by CSPC using innovative technology to encapsulate docetaxel in human serum albumin. Compared with conventional docetaxel injection, this novel formulation offers several advantages:

Safety: No premedication with corticosteroids is required, and it enables high-concentration and rapid administration, thereby improving safety and patient compliance.

Efficacy: It demonstrates potent anti-tumor activity in multiple preclinical tumor models and allows higher clinical dosing to further improve therapeutic effects.

Data from multiple clinical trials have consistently shown that HB1801 exhibited favorable efficacy and safety profiles, achieving the goal of reduced toxicity and enhanced efficacy. Several phase III trials of HB1801 in patients with breast cancer and gastric cancer are ongoing.

About Alphamab Oncology

Alphamab Oncology (Stock Code: 9966.HK) is an innovative biopharmaceutical company focused on oncology. Leveraging proprietary platforms-including single-domain antibodies, bispecific antibodies, glycan-specific conjugation, linker-payloads, dual-payload ADCs, and high-concentration subcutaneous formulations, the Company has built a differentiated and globally competitive pipeline, covering cutting-edge candidates in ADCs, bispecific antibodies, and single-domain antibodies.

One product has received market approval: Envafolimab (KN035, brand name: 恩维达^®), the world's first subcutaneously injected PD-(L)1 inhibitor, offering greater convenience and accessibility in cancer treatment. The NMPA has accepted the new drug application for KN026 (Anbenitamab Injection), a HER2 bispecific antibody, for second-line or later HER2-positive gastric cancer. Five bispecific ADC candidates have entered clinical stages, and next-generation ADC pipelines—such as dual-payload ADCs—are advancing rapidly. The Company has established strategic partnerships with organizations including CSPC, ArriVent, and Glenmark, covering both product development and technology platforms.

Our overarching mission is to make cancer manageable and curable by addressing unmet clinical needs in oncology. Alphamab Oncology is continuously dedicated to the development of effective, safe, and globally competitive anti-tumor drugs, enabling patients to achieve long-term, high-quality survival and delivering China-innovated cancer therapies to benefit patients worldwide.

SOURCE Alphamab Oncology