REPURCHASE AND WITHDRAWAL OF LISTING OF US$300 MILLION ZERO COUPON CONVERTIBLE BONDS DUE 2026

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.Pharmaron Beijing Co. Ltd.康龙化成(北京)新药技术股份有限公司 (a joint stock company incorporated in the People’s Republic of China with limited liability) (Stock Code: 3759) REPURCHASE AND WITHDRAWAL OF LISTING OF US$300 MILLION ZERO COUPON CONVERTIBLE BONDS DUE 2026 (STOCK CODE: 40725) Reference is made to the announcements (the “Announcements”) of Pharmaron Beijing Co.Ltd. (the “Company”) dated June 8 2021 June 9 2021 June 11 2021 June 18 2021 and June 21 2021 regarding the issuance of the US$300.0 million zero coupon convertible bonds by the Company due 2026 (the “Series 1 Bonds”) and the announcements of the Company dated May 30 2022 June 13 2022 March 30 2023 June 20 2023 July 26 2023 January 12 2024 and June 19 2024 regarding other matters related to the Series 1 Bonds unless otherwise defined capitalized terms used in this announcement shall have the same meanings as those defined in the Announcements.The Company hereby announces that it has voluntarily repurchased and cancelled all the outstanding principal amount of the Series 1 Bonds in the amount of US$1500000 on July 4 2024 in accordance with the terms and conditions of the Series 1 Bonds.As of the date of this announcement all Series 1 Bonds have been cancelled and no Series 1 Bonds remain outstanding. The Company has applied to The Stock Exchange of Hong Kong Limited for the withdrawal of the listing of the Series 1 Bonds. Such withdrawal of listing is expected to become effective upon the close of business on July 11 2024.By order of the Board Pharmaron Beijing Co. Ltd.康龙化成(北京)新药技术股份有限公司 Dr. Lou Boliang Chairman Beijing the PRC July 4 2024 As at the date of this announcement the Board of Directors comprises Dr. Lou Boliang Mr. Lou Xiaoqiang and Ms. Zheng Bei as executive Directors; Mr. Hu Baifeng and Mr. Li Jiaqing as non- executive Directors; Ms. Li Lihua Mr. Zhou Qilin Mr. Tsang Kwan Hung Benson and Mr. Yu Jian as independent non-executive Directors.