Alphamab Oncology Presented Clinical Data of KN026 Combined with Docetaxel in first-line treatment of HER2-positive recurrent/metastatic breast cancer at SABCS 2022

As of August 18,2022，the confirmed ORR for 55 evaluable subjects was 76.4% and DoR was 24.0 months. The disease control rate was 100% in 55 evaluable subjects.

The median follow-up for PFS was 16.6 months. The median PFS was calculated as 25.4 months and yet to become mature.

The median OS was not reached with 12,18 and 24 months OS rates at 93.0 %,91.2 % and 91.2 %,respectively.

In terms of safety,≥Grade 3 treatment-related adverse events (TRAEs) occurred in 22 patients (38.6%,22/57) and SAE in15.8%(9/57) patient。

SUZHOU,China,Dec. 12,2022 --Alphamab Oncology (stock code: 9966.HK) announced that data from phase II clinical study (clinical trial No.: KN026-201) of HER2 bispecific antibody KN026 in combination with Docetaxel for the treatment of patients with HER2-positive recurrent/metastatic breast cancer presented as a Spotlight Poster at the San Antonio Breast Cancer Symposium (SABCS 2022).

Presentation Format:Spotlight Poster Discussion

Poster Title:Efficacy and safety results of KN026,a HER2-targeted bispecific antibody combined with docetaxel in first-line treatment of HER2-positive recurrent/metastatic breast cancer

Poster ID:PD18-08

Corresponding author: Prof. Qingyuan Zhang,Harbin Medical University Cancer Hospital

launch time: December 9,2022,7:30AM-8:15 AM(CST)

KN026-201 is a phase II,open label,multi-center clinical study,evaluating the efficacy,safety,and tolerability of KN026 in combination with Docetaxel in first-line treatment of HER2-positive recurrent/metastatic breast cancer.

As of August 18,A total of 57 HER2-positive female patients with recurrent or metastatic breast cancer were enrolled. Patients received KN026 30 mg/kg combined with docetaxel 75 mg/m2 Q3W until disease progression,unacceptable toxicity,or other circumstances that require drug discontinuation. The primary endpoints were ORR and DOR assessed by investigators per RECIST 1.1; secondary endpoints are PFS,OS and safety outcomes,etc.

The confirmed ORR within 55 evaluable subjects was 76.4% (95% CI: 62.98,86.77) and DoR was 24.0 months (95% CI: 18.070,NE). The disease control rate was 100%. The median follow-up for PFS was 16.6 months (95%CI：15.15,19.29). Median PFS was 25.4 months (95% CI: 16.53,NE) and median OS was not reached. The median PFS was not yet mature. The 12-,18-and 24-month OS rates were 93.0 % (95% CI: 82.37,97.31),91.2 % (95% CI: 80.05,96.22) and 91.2 % (95% CI: 80.05,96.22),respectively.

In terms of safety,22/57). The incidence of serious adverse events was 15.8%(9/57),including 5.3%（3/57）for febrile neutropenia,3.5% （2/57）for white blood cell count decreased,and less than 2% for other SAEs. The incidence of SAE associated with KN026 was 8.8% (5/57).There were no deaths due to KN026 drug-related AEs in this study.

The results showed that KN026 was well tolerated and effective in combination with docetaxel in patients with advanced HER2-positive breast cancer,with an improvement in progression-free survival (PFS) and preliminary evidence of an overall survival (OS) benefit.

About KN026

KN026 is an anti-HER2 bispecific antibody invented by Alphamab Oncology using the proprietary Fc-based heterodimer bispecific platform technology called CRIB (Charge Repulsion Induced Bispecific). KN026 can bind two non-overlapping epitopes of HER2 simultaneously,leading to a dual HER2 signal blockade. KN026 has demonstrated potentially superior efficacy to Trastuzumab and Pertuzumab in combination,such as increased binding affinity,as well as better tumor inhibition in HER2-positive tumor cell lines. Additionally,KN026 has also shown inhibitory effect on tumor cells with medium or low HER2 expression or Trastuzumab-resistant cell lines.

KN026 received IND approval from the National Medical Products Administration (NMPA) of China and U.S. Food and Drug Administration (FDA) in 2018. Currently,it is in multiple clinical trials in China and the United States,for patients with breast cancer,or gastric cancer/gastroesophageal junction cancer,etc. Two phase III pivotal studies of KN026 combined with chemotherapy and the chemo-free regimen of KN026/KN046 combo for the treatment of gastric cancer are ongoing. The results of prior clinical studies showed that KN026 has good efficacy and safety profiles,even in heavily pretreated patients with HER2-positive breast cancer.

In August 2021,the company entered an agreement with JMT-Bio,a wholly-owned subsidiary of CSPC Pharmaceutical Group Co.,Ltd. (stock code: 1093.HK),for the development and commercialization of KN026 in Mainland China. According to the terms of the agreement,JMT-Bio will obtain the exclusive license rights of KN026 for the development and commercialization in the indications of breast cancer and gastric or gastroesophageal junction cancers (GC/GEJ) in Mainland China (excluding Hong Kong,Macau and Taiwan).

About Alphamab Oncology

Alphamab Oncology is a leading biopharmaceutical company dedicated to the discovery,development manufacturing and commercialization of world-class innovative biotherapeutics for cancer treatment. On December 12,2019,Alphamab Oncology was listed on the Main Board of Hong Kong Stock Exchange,with the stock code:9966.

We have converged a professional R&D team led by top scientists,and have a complete industrial chain from early research and development of innovative drugs,process development,commercial production to clinical research.

With multiple in-house proprietary platforms of bispecifics,protein engineering and antibody screening,Alphamab Oncology has established a globally competitive and differentiated pipeline which consists of tumor monoclonal antibodies,bispecific antibodies,and antibody-drug conjugates. Among them,2 varieties were selected into the national special project of " New Drug Development",and 3 varieties were granted 4 orphan drug qualifications by FDA. The world's first subcutaneous PD-L1 inhibitor injection (Envafolimab) has been obtained the market approval by the Chinese National Medical Products Administration. More than 30 clinical studies have been carried out in 6 varieties in China,the United States and Australia,among which 8 studies of 3 varieties have entered the critical clinical stage in China and the United States.

To make cancer manageable and curable，Alphamab Oncology has always been guided by clinical value and patient needs,and focuses on the development of innovative,safe and affordable anti-tumor drugs to benefit patients in China and around the world.

Visit http://www.alphamabonc.com for more information.