Akeso, Inc. — Regulatory Filings 2021

Jul 13, 2021

Hong Kong Exchanges and Clearing Limited and The Stock Exchange of Hong Kong Limited take no responsibility for the contents of this announcement, make no representation as to its accuracy or completeness and expressly disclaim any liability whatsoever for any loss howsoever arising from or in reliance upon the whole or any part of the contents of this announcement.

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Akeso, Inc. 康方生物科技（開曼）有限公司

(Incorporated in the Cayman Islands with limited liability) (Stock Code: 9926)

VOLUNTARY ANNOUNCEMENT

CD47 MONOCLONAL ANTIBODY (AK117) COMPLETED PHASE I DOSE ESCALATION TRIAL AND OBTAINED APPROVAL TO INITIATE CLINICAL TRIAL IN COMBINATION WITH AZACITIDINE FOR TREATMENT OF ACUTE MYELOID LEUKEMIA

This announcement is made by Akeso, Inc. (the ‘‘Company‘‘, together with its subsidiaries, the ‘‘Group’’) on a voluntary basis to inform the shareholders and potential investors of the Company about the latest business advancement of the Group.

The board of directors of the Company (the ‘‘Board’’) is pleased to announce that, CD47 monoclonal antibody (research and development code: AK117), a second-generation novel drug for immuno-oncology therapy independently developed by the Company, has completed phase I dose escalation trial in Australia. AK117 resulted in no dose-limiting toxicity (‘‘DLT’’) and no anemia of clinical significance in subjects in all dose escalation cohorts (with 0.3 mg/kg to 45 mg/kg administered once-weekly (‘‘QW’’)), and was well tolerated by subjects in all cohorts. Low-dose priming was not required.

The Company has obtained approval from the National Medical Products Administration (the ‘‘NMPA’’) of the People’s Republic of China to initiate phase Ib/II clinical trial of AK117 in combination with azacitidine for the treatment of acute myeloid leukemia (‘‘AML’’). AK117, a second-generation CD47 monoclonal antibody, has a significantly improved safety profile compared to the first-generation CD47 monoclonal antibody, and AK117 in combination with azacitidine is expected to perform better than similar drugs in the treatment of AML. Previous studies of AK117 in myelodysplastic syndromes (‘‘MDS’’) have shown its advantages of safety and the majority of MDS patients had hematologic improvement while receiving AK117 treatment. To date, clinical trials of AK117 in both solid tumors and hematologic tumors have been initiated and began patient dosing.

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AML is a group of highly heterogeneous diseases with clonal proliferation abnormalities of hematopoietic stem cells and is the most common type of adult acute leukemia. CD47 is highly expressed on the surface of several tumor cells, including solid tumors and hematologic tumors, and is associated with poor prognosis. CD47 blockade stimulates phagocytosis of tumor cells by macrophages and promotes adaptive immune response. Preclinical data showed that CD47 monoclonal antibody in combination with azacitidine can further induce endogenous expression of calreticulin on the cell surface, thereby further enhancing the phagocytosis of tumors by macrophages. At the same time, there are clinical data showing that CD47 monoclonal antibody in combination with azacitidine is significantly more effective than azacitidine alone in treating AML subjects who are not suitable for chemotherapy at first treatment, and is safe and well tolerated.

INFORMATION ABOUT AK117 (CD47 MONOCLONAL ANTIBODY)

AK117 is a novel humanized IgG4 mAb independently developed by the Company. It can bind with CD47 expressed on tumor cells to prevent the interaction between CD47 and its receptor, SIRPα, expressed on macrophages so as to enhance phagocytosis to inhibit the growth of tumor cells. Previously published data demonstrated exceptional safety profile. AK117 resulted in no DLT and no anemia of clinical significance in subjects in all doseescalation cohort (the highest dose cohort was 45 mg/kg QW), and was well tolerated by subjects in all cohorts. The CD47 receptor occupancy rate (RO) of the peripheral blood T cells has reached and maintained at 100% in the 3 mg/kg cohort.

INFORMATION ABOUT THE COMPANY

The Company is a biopharmaceutical company dedicated to the research, development, manufacturing and commercialization of new innovative antibody drugs that are affordable to patients worldwide. Since the Company’s establishment, the Company has established an end-to-end comprehensive drug development platform (ACE Platform) and system, encompassing fully integrated drug discovery and development functions, including target validation, antibody drug discovery and development, CMC production process development, and GMP compliant scale production. The Company has also successfully developed a bi-specific antibody drug development technology (Tetrabody technology). The Company currently has a pipeline of over 20 innovative drugs for the treatment of major diseases like tumors, autoimmune diseases, inflammation and metabolism diseases, 13 of which have entered clinical stage, including two first-in-class bi-specific antibody drugs (PD-1/CTLA-4 and PD-1/VEGF). The Company’s vision is to become a global leading biopharmaceutical company through research and development of high efficacy and breakthrough new drugs that are first-in-class and best-in-class therapies.

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DEFINITIONS AND GLOSSARY OF TECHNICAL TERMS

CMC chemistry, manufacturing, and controls processes in the development, licensure, manufacturing, and ongoing marketing of pharmaceutical products CTLA-4 cytotoxic T-lymphocyte-associated protein 4, which downregulates T cell immune response to cancer cells

GMP the Good Manufacturing Practice, which comprise guidelines and regulations from time to time issued pursuant to the Drug Administration Law of the People’s Republic of China 《( 中 華 人 民共 和國藥品管 理法 》) as part of quality assurance PD-1 programmed cell death protein 1, an immune checkpoint receptor expressed on T-cells, B-cells and macrophages. The normal function of PD-1 is to turn off the T-cell mediated immune response as part of the process that discourages a healthy immune system from attacking other pathogenic cells in the body. When PD-1 on the surface of T-cells attaches to certain proteins on the surface of a normal cell or cancer cell, T-cells will turn off its ability to kill the cell VEGF vascular endothelial growth factor, a family of cytokines critical for the growth and development of cancer cells. There are three main subtypes of VEGFs and VEGF receptors, including VEGFR-1, VEGFR-2 and VEGFR-3

Warning under Rule 18A.08(3) of the Rules Governing the Listing of Securities on The Stock Exchange of Hong Kong Limited: There is no assurance that the CD47 monoclonal antibody (AK117) will ultimately be successfully developed and marketed by the Company. Shareholders and potential investors of the Company are advised to exercise caution when dealing in the shares of the Company.

By Order of the Board Akeso, Inc. Dr. XIA Yu

Chairwoman and executive director

Hong Kong, July 13, 2021

As at the date of this announcement, the Board comprises Dr. XIA Yu as chairwoman and executive director, Dr. LI Baiyong, Dr. WANG Zhongmin Maxwell and Mr. XIA Yu (Ph.D.) as executive directors, Mr. XIE Ronggang and Dr. ZHOU Yi as non-executive directors, and Dr. ZENG Junwen, Dr. XU Yan and Mr. TAN Bo as independent non-executive directors.

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