Shanghai Junshi Biosciences Co., Ltd. — Proxy Solicitation & Information Statement 2025

Sep 15, 2025

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.

君实生物 TopAlliance

SHANGHAI JUNSHI BIOSCIENCES CO., LTD.* 上海君寶生物醫藥科技股份有限公司

(a joint stock company incorporated in the People's Republic of China with limited liability)

(Stock code: 1877)

ADJOURNMENT OF EXTRAORDINARY GENERAL MEETING

References are made to (i) the notice of extraordinary general meeting (the "EGM") of Shanghai Junshi Biosciences Co., Ltd.* (the "Company") dated 5 September 2025 (the "Notice of EGM"); and (ii) the circular of the Company dated 5 September 2025 in respect of the EGM (the "EGM Circular"). Unless the context requires otherwise, capitalised terms used in this announcement shall have the same meanings as those defined in the Notice of EGM and the EGM Circular.

The Board hereby announces that the EGM, which was originally scheduled to be held at 2:40 p.m. on Friday, 26 September 2025 will be adjourned and rescheduled to 2:40 p.m. on Monday, 29 September 2025 to allow for sufficient time for the Shareholders to consider the additional special resolutions to be proposed at the EGM. For further details, please refer to the supplemental EGM circular published by the Company on the date of this announcement. The venue of the EGM will remain unchanged and the EGM will be held at 15th Floor, Building 7, No. 6, Lane 100, Pingjiaqiao Road, Pudong New Area, Shanghai, the People's Republic of China.

The period of the closure of the register of members of H Shares for determining the entitlements of H Shareholders to attend and vote at the EGM remains unchanged (i.e. from Monday, 22 September 2025 to Friday, 26 September 2025 (both dates inclusive)). The record date for determining the eligibility of the shareholders to attend and vote at the EGM will remain to be Friday, 26 September 2025. Any person who becomes a H Shareholder during the period from Friday, 26 September 2025 to Monday, 29 September 2025 (both days inclusive) is not entitled to attend or vote at the EGM. In order to be eligible to attend and vote at the EGM, all transfers of H Shares accompanied by the relevant share certificates and transfer forms must be lodged with the Company's H Share registrar, Tricor Investor Services Limited at 17/F, Far East Finance Centre, 16 Harcourt Road, Hong Kong, before 4:30 p.m. on Friday, 19 September 2025, being the last share registration date.

A supplemental proxy form has been published by the Company on the date of this announcement. For holders of H Shares, the supplemental form(s) of proxy for the 2025 First EGM shall be lodged at the Company's Hong Kong H share registrar no later than 24 hours before the time fixed for holding the EGM or any adjournment thereof (the "Closing Time").

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If the supplemental proxy form is not lodged with the Company’s H Share registrar, the proxy form accompanying the EGM Circular will be treated as a valid form of proxy lodged by him/her if correctly completed. The proxy so appointed by the H Shareholder shall be required to vote in such manner as he/she may be directed under the proxy form accompanying the EGM Circular, and in respect of the additional special resolutions as set out in the supplemental notice of EGM and the supplemental proxy form, the proxy will be entitled to vote at his/her discretion or to abstain from voting on such resolutions.

If the supplemental proxy form is lodged with the Company’s H Share registrar before the Closing Time, the supplemental proxy form will revoke and supersede the proxy form accompanying the EGM Circular previously lodged by the H Shareholder. The supplemental proxy form will be treated as a valid form of proxy lodged by the H Shareholders if correctly completed.

If the supplemental proxy form is lodged with the Company’s H Share registrar after the Closing Time, the supplemental proxy form will be invalid. However, it will still revoke the proxy form accompanying the EGM Circular previously lodged by the H Shareholder, and any vote that may be cast by the purported proxy will not be counted in any poll which will be taken on the proposed resolutions. Accordingly, H Shareholders are advised not to lodge the supplemental proxy form after the Closing Time. If such H Shareholders wish to vote at the EGM, they will have to attend in person and vote at the EGM themselves.

Saved as disclosed in this announcement, the supplemental EGM circular, supplemental notice of EGM and supplemental proxy form, all information and contents as set out in the EGM Circular, the Notice of EGM and proxy form for the EGM remain unchanged.

By order of the Board
Shanghai Junshi Biosciences Co., Ltd.*
Mr. Xiong Jun
Chairman

Shanghai, the PRC, 15 September 2025

As at the date of this announcement, the Board of Directors of the Company comprises Mr. Xiong Jun, Dr. Li Ning, Dr. Zou Jianjun, Mr. Li Cong, Mr. Zhang Zhuobing, Dr. Yao Sheng, Dr. Wang Gang and Dr. Li Xin as executive Directors; Mr. Tang Yi as a non-executive Director; and Mr. Zhang Chun, Dr. Feng Xiaoyuan, Dr. Yang Yue, Mr. Li Zhongxian and Ms. Lu Kun as Independent Non-executive Directors.

• For identification purpose only