Suzhou, China, June 1, 2026 - Alphamab Oncology (stock code: 9966.HK) today announced that the significant results from the Phase III clinical study (KN026-004) of HER2 bispecific antibody Anbenitamab (KN026, brand name: 恩尼妥®), 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 albumin-bound Docetaxel (HB1801) from CSPC as neoadjuvant treatment of breast cancer, have been presented at the Late-Breaking Abstract (LBA) Oral Presentation Session of the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting. This study is the first Phase III clinical trial worldwide to directly demonstrate that a bispecific antibody has superior efficacy to the combination of two monospecific antibodies targeting the same tumor antigen, highlighting the leadership and superiority of Alphamab's platform technology.
Anbenitamab was approved for marketing by the National Medical Products Administration (NMPA) in May 2026. It has demonstrated overall survival data in second‑line and above advanced gastric cancer that set a new historical record, making it the first domestically developed HER2 bispecific antibody approved for marketing in China. As the world’s largest and most influential grand event in oncology, the LBA Oral Presentation at the ASCO Annual Meeting ranks among its highest-level academic presentations. The inclusion of Anbenitamab’s research data fully proves its excellent clinical value and great application potential in the treatment of HER2-positive breast cancer.
Title: Anbenitamab plus albumin-bound docetaxel (nab-docetaxel)±carboplatin (Cb) versus trastuzumab and pertuzumab plus docetaxel (THP)±Cb as neoadjuvant therapy for HER2-positive early or locally advanced breast cancer: A randomized, open-label, multicenter, phase 3 trial
Abstract Number: LBA660
Principal Investigator: Professor Zhimin Shao, Fudan University Shanghai Cancer Center
Presentation Time: May 30, 2026, 3:39-3:51 PM CDT
KN026-004 is a randomized, controlled, open-label, multicenter Phase III clinical study designed to evaluate the efficacy and safety of Anbenitamab plus HB1801 ± carboplatin versus trastuzumab plus pertuzumab and docetaxel ± carboplatin as neoadjuvant therapy for early or locally advanced HER2-positive breast cancer. The primary endpoint is tpCR assessed by a blinded independent review committee (BIRC).
METHOD
As of January 28, 2026, a total of 521 patients were enrolled and randomized 1:1 to the experimental group (KN026 + HB1801 ± carboplatin) or the control group (trastuzumab + pertuzumab + docetaxel ± carboplatin), all receiving 6 cycles of treatment. Patients were stratified at enrollment based on three factors: (i) clinical stage; (ii) hormone receptor status; and (iii) planned carboplatin use.
RESULTS
Efficacy:
● Based on BIRC assessment, the tpCR rate in the experimental group was 62.4% (95% CI: 56.2-68.2), significantly higher than the 51.2% (95% CI: 44.9-57.4) in the control group, with a one-sided P value of 0.0036, indicating a statistically significant difference. Stratified analysis by carboplatin use also showed that the tpCR rate in the experimental group was consistently superior to that in the control group (with carboplatin subgroup: 66.7% vs. 54.5%; without carboplatin subgroup: 59.2% vs. 48.6%).
● Consistent results were observed for investigator‑assessed tpCR rates: 63.9% (95% CI: 57.8-69.7) in the experimental group vs. 51.2% (95% CI: 44.9-57.4) in the control group, one‑sided P = 0.0011, further validating the efficacy of the regimen. Stratified analysis by carboplatin use again demonstrated significantly higher tpCR rates in the experimental group (with carboplatin subgroup: 70.3% vs. 53.6%; without carboplatin subgroup: 59.2% vs. 49.3%).
● The BIRC‑assessed tpCR benefits were consistent across most prespecified subgroups, including those stratified by hormone receptor status, clinical stage, and planned carboplatin use. The BIRC‑assessed breast pathological complete response (bpCR) rate was also significantly higher in the experimental group (64.6% vs. 55.0%; one‑sided P = 0.0099), and the investigator‑assessed bpCR rate was 65.8% in the experimental group vs. 55.4% in the control group (one‑sided P = 0.0057).
Safety:
● The incidence of grade 3 or above treatment-emergent adverse events (TEAEs) was 29.3% in the experimental group versus 28.3% in the control group, indicating similar rates between the two groups. The proportion of patients who had any study drug interruption due to TEAEs was 5.7% in the experimental group and 7.4% in the control group, while the proportion of patients who permanently discontinued study treatment due to TEAEs was 4.9% and 3.5%, respectively.
● The most common grade 3 or above TEAEs in the experimental group were neutropenia (11.4%), leukopenia (7.6%), anemia (6.5%), thrombocytopenia (3.0%), and diarrhea (3.0%). In the control group, the most common grade 3 or above TEAEs were neutropenia (10.9%), leukopenia (8.5%), anemia (5.0%), and diarrhea (2.7%). The safety profiles were primarily hematologic and gastrointestinal toxicities, comparable between groups, with no new safety signals identified. Toxicities were consistent with the known safety profiles of the respective single agents, and no notable additive toxicity was observed.
CONCLUSION
The study results demonstrate that the Anbenitamab plus HB1801 ± carboplatin regimen significantly improved tpCR rate compared with standard dual HER2 blockade plus chemotherapy as neoadjuvant therapy in patients with early or locally advanced HER2-positive breast cancer, with a manageable safety profile. These results support Anbenitamab-based regimen as a potential new standard of care, offering a more effective treatment option for this patient population.
About 恩尼妥® (Anbenitamab Injection)
恩尼妥® (Anbenitamab injection, KN026) is an anti-HER2 bispecific antibody independently developed by the Company 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 antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) effects while promoting the down-regulation of HER2 receptors on the cell surface.
In May 2026, 恩尼妥® obtained approval for marketing in China for use in combination with chemotherapy for the treatment of adult patients with locally advanced or metastatic HER2 positive gastric cancer/gastroesophageal junction cancer (GC/GEJ) who have previously received at least one trastuzumab-containing regimen. Currently, multiple registrational clinical trials of Anbenitamab for indications such as first-line treatment of HER2 positive breast cancer (BC), neoadjuvant and adjuvant treatment of HER2 positive BC and first-line treatment of HER2 positive GC/GEJ are ongoing.
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 and GC/GEJ in Mainland China (excluding Hong Kong, Macau and Taiwan).
About HB1801
HB1801 is one of the representative drugs independently developed by the CSPC's nanomedicine technology platform. HB1801 encapsulates docetaxel in human serum albumin. Because it does not contain Tween-80 and ethanol, it has the following advantages compared with docetaxel injection: (1) Safety: no hormone pretreatment is required, it can be administered rapidly at high concentration, with higher safety and patient compliance; (2) Efficacy: it has significant effects in multiple preclinical tumor models and early-stage clinical studies, and can be administered at a larger dose clinically, further improving efficacy. Currently, HB1801 has entered the pivotal registrational Phase III clinical trial stage in indications such as breast cancer and gastric cancer.
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.
Two products have 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; and Anbenitamab (KN026, brand name: 恩尼妥®), the first domestically developed HER2 bispecific antibody approved for marketing in China, redefining the standard of treatment for second‑line HER2‑positive gastric cancer. Six bispecific ADC, dual-payload ADC candidates have entered clinical stages, and next-generation ADC pipelines 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.
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