Akeso, Inc. — Regulatory Filings 2022

Jan 20, 2022

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

RESULTS OF PHASE IB/II CLINICAL TRIAL OF CADONILIMAB (PD-1/CTLA-4 BI-SPECIFIC ANTIBODY) COMBINED WITH CHEMOTHERAPY AS FIRST-LINE THERAPY FOR ADVANCED GASTRIC CANCER/GASTROESOPHAGEAL JUNCTION CANCER PUBLISHED AT THE ASCO GI 2022

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’’) announces that the results of phase Ib/II clinical trial of Cadonilimab (PD-1/CTLA-4 bispecific antibody, research and development code: AK104), the world’s first-in-class novel immuno-oncology drug independently developed by the Company, combined with capecitabine plus oxaliplatin (XELOX) as first-line therapy for advanced gastric cancer or gastroesophageal junction cancer (GC/GEJ) were published at the ASCO Gastrointestinal Cancers Symposium 2022 (ASCO GI).

This trial was a multicenter and open-label clinical trial (Clinical Trial number: NCT03852251) in patients with unresectable locally advanced or metastatic GC/GEJ who had not received prior systemic therapy. PD-L1 expression levels were not considered for enrolled patients, with an exception of known HER2-positive patients. The primary endpoints of the trial were the safety and objective response rate (ORR).

As of August 13, 2021, a total of 96 patients were included in the trial, with a median follow-up period of 9.95 months. The research data has shown the excellent antitumor activity and safety of Cadonilimab combined with chemotherapy as the first-line therapy for GC/GEJ, and Cadonilimab combined with chemotherapy is expected to bring a choice of first-line treatment of higher efficiency for patients with unresectable locally advanced or metastatic GC/GEJ who have not received prior therapy.

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In terms of effectiveness, among 88 evaluable subjects:

• . The ORR was 65.9% (58/88); the disease control rate (DCR) was up to 92% (81/88); the median duration of response (DoR) was 6.93 months (95% CI, 4.60, 11.20). Among which, 2 subjects achieved complete response and 56 subjects achieved partial response.

• . The median progression-free survival (mPFS) was 7.1 months (95% CI, 5.55, 10.48).

• . The median overall survival (mOS) was 17.41 months (95% CI, 12.35, NE).

• . The mOS of patients with PD-L1 average consolidated positive score (CPS)≥1 was 17.41 months; the mOS of subjects with CPS<1 was 14.65 months.

• . The mPFS of patients with CPS≥5 was 9.36 months, and the mOS was NR. The further follow-up results are pending.

In terms of safety, Cadonilimab combined with XELOX has good safety with an incidence rate of treatment-related adverse event (TRAE) of grade≥3 at 62.5%, and no new safety signal was found.

Currently, the phase III pivotal trial of Cadonilimab combined with XELOX versus placebo combined with XELOX as first-line therapy for advanced gastric cancer or gastroesophageal junction cancer has commenced in August 2021 and is in smooth progress (Clinical Trial number: NCT05008783). The Company is expected to submit the NDA for this indication in 2024.

INFORMATION ABOUT CADONILIMAB (PD-1/CTLA-4 BI-SPECIFIC ANTIBODY, AK104)

Cadonilimab (AK104) is a novel first-in-class PD-1/CTLA-4 bi-specific immuno-oncology backbone drug independently developed by the Company, and its major indications include lung cancer, liver cancer, stomach cancer, cervical cancer, renal cancer, esophageal squamous cell cancer, nasopharyngeal carcinoma and other malignant tumors. The periodic research data show that, as compared with the combination therapy of PD-1 and CTLA-4, Cadonilimab has much lower toxicity and demonstrates promising safety profile and efficacy. Based on the positive effects of Cadonilimab obtained in the clinical trial of recurrent/metastatic cervical cancer, CDE accepted the new drug application of Cadonilimab for the treatment of recurrent/metastatic cervical cancer in September 2021 and granted priority review designation. Cadonilimab is therefore expected to be the world’s first-in-class PD-1 based bi-specific antibody approved for market launch. In addition, a global phase III clinical trial of Cadonilimab plus platinum-based chemotherapy combined with/without bevacizumab in the first-line treatment of persistent, recurrent or metastatic cervical cancer was initiated in May 2021.

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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.

DEFINITIONS AND GLOSSARY OF TECHNICAL TERMS

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NE not evaluable NR not reached VEGF vascular endothelial growth factor, a family of cytokines critical for the growth and development of cancer cells. There are three main VEGF receptors and subtypes of VEGFs, 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 Cadonilimab (PD1/ CTLA-4 bi-specific antibody, AK104) 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, January 21, 2022

As at the date of this announcement, the Board of the Company 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 nonexecutive directors, and Dr. ZENG Junwen, Dr. XU Yan and Mr. TAN Bo as independent non-executive directors.

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