CHENGDU,China,Nov. 27,2024 --SichuanKelun-Biotech Biopharmaceutical Co.,Ltd. (the "Company") announced that the Company received marketing authorization in China from National Medical Products Administration (NMPA) for the first domesticallydevelopedtrophoblast cell-surface antigen 2 (TROP2)-directed antibody–drug conjugate (ADC) sacituzumab tirumotecan (sac-TMT,formerly SKB264/MK-2870)for adult patients with unresectable locally advanced or metastatic triple negative breast cancer (TNBC) who have received at least two prior systemic therapies (at least one of them for advanced or metastatic setting). This is the first domestically developed TROP2 ADC approved for marketing in China and the first domestically developed ADC fully approved for marketing in China.

The approval is based on the positive results from a randomized,controlled,phase 3 OptiTROP-Breast01 study in adult patients with unresectable locally advanced or metastatic TNBC who have received at least two prior systemic therapies (at least one of them for advanced or metastatic setting). Sac-TMT demonstrated statistically significant and clinically meaningful improvement in both progression-free survival (PFS) and overall survival (OS) compared to chemotherapy. The results were presented at the special clinical science symposium fornext-generation ADCs at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting in May 2024.

Previously,NMPA has accepted two supplemental new drug applications (sNDA) seeking the approvals of sac-TMT monotherapy for the treatment of patients with locally advanced or metastatic EGFR-mutant non-small cell lung cancer (NSCLC) following progression onEGFR-TKI therapy only,or both EGFR-TKI and platinum-based chemotherapy,respectively.

Dr. Micheal Ge,CEO of Kelun-Biotech said,"It is a great pleasure to share with you the important milestone moment of the successful approval and launch of sacituzumab tirumotecan in China,which is a significant achievement of Kelun-Biotech's years of deep-rooted source innovation. As the company's first proprietary TROP2 ADC innovative drug,the successful launch of sacituzumab tirumotecan officially opens up a new pattern for the treatment of patients with 2L+advanced TNBC. We expect that its excellent clinical efficacy and safety resultswill significantly enhance the clinical benefits and improve the quality of life of patients with advanced TNBC. In the future,we will continue to explore the clinical value of sacituzumab tirumotecan in other indications,maximize the market potential of sacituzumab tirumotecan,and satisfy the clinical needs of patients nationwide."

ABOUT MARKET VALUE

Breast cancer is a threat to women's lives and health. Among them,triple-negative breast cancer has unique biological behavioral characteristics,and is also known as the "most toxic" breast cancer. 2022 analysis of China's malignant tumor epidemiology data shows that there are 357,000 new cases of breast cancer and 75,000 deaths in Chinese women annually [1]. In the absence of effective therapeutic targets for triple-negative breast cancer,chemotherapy is the most important systemic treatment in the clinic [2],but it often has poor efficacy and high toxicity and side effects,and the prognosis is different from other subtypes of breast cancer [3],it is vital to explore more therapeutic means to improve the clinical benefit.

ABOUT sac-TMT

Sac-TMT,a core product of the Company,is a novel human TROP2 ADC in which the Company has proprietary intellectual property rights,targeting advanced solid tumors such as NSCLC,breast cancer (BC),gastric cancer (GC),gynecological tumors,among others. Sac-TMT is developed with a novel linker to conjugate the payload,a belotecan-derivative topoisomerase I inhibitor with a drug-to-antibody-ratio (DAR) of 7.4. Sac-TMT specifically recognizes TROP2 on the surface of tumor cells by recombinant anti-TROP2 humanized monoclonal antibodies,which is then endocytosed by tumor cells and releases KL610023 intracellularly. KL610023,as a topoisomerase I inhibitor,induces DNA damage to tumor cells,which in turn leads to cell-cycle arrest and apoptosis. In addition,it also releases KL610023 in the tumor microenvironment. Given that KL610023 is membrane permeable,it can enable a bystander effect,or in other words kill adjacent tumor cells.

In May 2022,the Company licensed the exclusive rights to MSD (the tradename of Merck & Co.,Inc.,Rahway,NJ,USA) to develop,use,manufacture and commercialize sac-TMT in all territories outside of Greater China (includes Mainland China,Hong Kong,Macao,and Taiwan).

ABOUT KELUN-BIOTECH

Kelun-Biotech（6990.HK）is a holding subsidiary of Kelun Pharmaceutical (002422.SZ),which focuses on the R&D,manufacturing,commercialization and global collaboration of innovative biological drugs and small molecule drugs. The company focuses on major disease areas such as solid tumors,autoimmune,inflammatory,and metabolic diseases,and in establishing a globalized drug development and industrialization platform to address the unmet medical needs in China and the rest of world. The Company is committed to becoming a leading global enterprise in the field of innovative drugs. At present,the Company has more than 30 ongoing key innovative drug projects,of which 1 project has been approved for marketing,3 projects are in the NDA stage,and more than 10 projects are in the clinical stage. The company has established one of the world's leading proprietary ADC platforms,OptiDC™,and has 1 ADC project approved for marketing,1 ADC project in NDA stage,and multiple ADC or novel ADC projects in clinical or preclinical research stage. For more information,please visit https://kelun-biotech.com/.

Reference

[1].Han,Bingfeng,et al. "Cancer incidence and mortality in China,2022." Journal of the National Cancer Center 4.1 (2024): 47-53.

[2]. [Chinese Society of Clinical Oncology (CSCO) (2024)] Guidelines for the diagnosis and treatment of breast cancer.

[3]. https://seer.cancer.gov/statfacts/html/breast-subtypes.html.