SinoMab BioScience Limited — AGM Information 2021

May 11, 2021

Hong Kong Exchanges and Clearing Limited and The Stock Exchange of Hong Kong Limited take no responsibility for the contents of this notice, 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 notice.

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SinoMab BioScience Limited 中國抗體製藥有限公司

(Incorporated in Hong Kong with limited liability)

(Stock code: 3681)

SUPPLEMENTAL NOTICE OF ANNUAL GENERAL MEETING

Reference is made to the notice (the “Notice”) of the 2021 AGM dated 29 April 2021 of the Company which sets out the date, time and place of the 2021 AGM as well as the resolutions at the 2021 AGM for Shareholders’ consideration and approval.

A SUPPLEMENTAL NOTICE IS HEREBY GIVEN THAT the 2021 AGM will be held as scheduled at 10:00 a.m. on Tuesday, 15 June 2021 at Theater R1, 10/F, United Centre, 95 Queensway, Admiralty, Hong Kong, at which, in addition to the resolutions contained in the Notice, the following resolution proposed by the Board will also be considered and approved at discretion. Save as mentioned herein, all information and contents set out in the Notice remain unchanged.

ORDINARY RESOLUTION

1. To elect Dr. Chi Ming LEE as an independent non-executive director of the Company, with effect from the conclusion of the 2021 AGM for an initial term of three years, and to authorise the board of directors of the Company to fix his Directors’ remuneration and to enter into a letter of appointment with him.

By Order of the Board SinoMab BioScience Limited Dr. Shui On LEUNG

Executive Director, Chairman and Chief Executive Officer

Hong Kong, 12 May 2021

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Notes:

1. Details about the above resolution are contained in the supplemental circular (the “ Supplemental Circular ”) of the Company dated 12 May 2021. Unless the context requires otherwise, the terms used in this Supplemental Notice of 2021 AGM shall have the meanings same as those used in the Supplemental Circular.

2. Since the Original Proxy Form issued with the circular dated 29 April 2021 does not contain the new resolution in the Supplemental Notice of 2021 AGM, the Revised Proxy Form is issued with the Supplemental Circular.

3. All resolutions at the 2021 AGM will be taken by poll (except where the chairman decides to allow a resolution relating to a procedural or administrative matter to be voted on by a show of hands) pursuant to the Listing Rules. The results of the poll will be published on the websites of Hong Kong Exchanges and Clearing Limited and the Company in accordance with the Listing Rules.

4. Any Shareholder entitled to attend and vote at the 2021 AGM is entitled to appoint a proxy or if he/she is the holder of two or more Shares, more than one proxy to attend and on a poll, vote instead of him/her. A proxy need not be a Shareholder. If more than one proxy is appointed, the number of Shares in respect of which each such proxy so appointed must be specified in the relevant form of proxy. Every Shareholder present in person or by proxy shall be entitled to one vote for each share held by him/her.

5. In order to be valid, this Revised Proxy Form, and any authority, if any, under which it is signed, or a copy of such power or authority, must be deposited at the Company’s share registrar in Hong Kong, Computershare Hong Kong Investor Services Limited, at 17M Floor, Hopewell Centre, 183 Queen’s Road East, Wanchai, Hong Kong not less than 48 hours (excluding any part of a day that is a public holiday) before the time appointed for the meeting (i.e. not later than 10:00 a.m. on Friday, 11 June 2021 (Hong Kong time)) or the adjourned meeting (as the case may be). Completion and return of the form of proxy shall not preclude a Shareholder from attending and voting in person at the meeting or poll concerned and, in such event, the instrument appointing a proxy shall be deemed to be revoked.

6. For any Shareholder who has submitted the Original Proxy Form according to the instructions in the Notice, please note that:

7. (i) If the Shareholder has not submitted the Revised Proxy Form, the Original Proxy Form (if properly completed) shall be deemed as a valid proxy from submitted by the Shareholder. The proxy appointed according to the Original Proxy Form shall be entitled to vote according to the instructions given by the Shareholder or to vote at his/her discretion (if no such instructions were given) at the 2021 AGM on the resolutions proposed in the Notice, and to vote at his/her discretion on the new resolution set out in the Supplemental Notice of 2021 AGM;

8. (ii) If the Shareholder has submitted the Revised Proxy Form prior to the deadline set out in the Notice, then the Revised Proxy Form (if properly completed) shall be deemed as a valid proxy form submitted by the Shareholder. The Original Proxy Form shall be deemed to be revoked. The proxy appointed pursuant to the Revised Proxy Form shall be entitled to vote according to the instructions given previously by the Shareholder or to vote at his/her discretion (if no such instructions were given) on any resolution (including the new resolution set out in the Supplemental Notice of 2021 AGM) proposed in an appropriate manner at the 2021 AGM; and

9. (iii) If the Shareholder submitted the Revised Proxy Form after the designated time, or the Revised Proxy Form submitted is improperly completed, the Revised Proxy Form will be invalid. The Original Proxy Form, if properly completed, will be treated as a valid proxy form submitted by the Shareholder. The arrangement as mentioned in (i) above shall apply as if no Revised Proxy Form was submitted.

10. For determining the entitlement to attend and vote at the meeting, the register of members of the Company will be closed from Wednesday, 9 June 2021 to Tuesday, 15 June 2021, both dates inclusive, during which period no transfer of shares will be registered. In order to be eligible to attend and vote at the 2021 AGM, unregistered holders of Shares shall ensure that all transfer documents accompanied by the relevant share certificates must be lodged with the Company’s share registrar in Hong Kong, Computershare Hong Kong Investor Services Limited, at Shops 1712-1716, 17th Floor, Hopewell Centre, 183 Queen’s Road East, Wanchai, Hong Kong for registration not later than 4:30 p.m. on Tuesday, 8 June 2021.

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1. If a tropical cyclone warning signal number 8 or above is hoisted, or “extreme conditions” caused by super typhoons or a black rainstorm warning is/are in force at or at any time after 6:00 a.m. on Tuesday, 15 June 2021, the 2021 AGM will not be held on 15 June 2021 but will be postponed to a later date and if postponed, the Company will as soon as practicable post an announcement on the websites of Hong Kong Exchanges and Clearing Limited and the Company. Shareholders may contact Customer Service Hotline of Computershare Hong Kong Investor Services Limited at (852) 2862 8555 from 9:00 a.m. to 5:00 p.m., Monday to Friday (excluding public holidays) for any enquiry regarding the aforesaid arrangement.

2. References to time and dates in this notice are to Hong Kong time and dates.

3. Please refer to the Notice for details about other resolutions to be submitted for consideration and approval at the 2021 AGM, eligibility of shareholders to attend the 2021 AGM, appointment of proxies, registration procedures, closure of register of members and other matters.

As at the date of this notice, the executive Director is Dr. Shui On LEUNG, the non-executive Directors are Dr. Haigang CHEN, Mr. Xun DONG, Mr. Senlin LIU, Ms. Wenyi LIU, Mr. Huiyuan MA and Mr. Jing QIANG, and the independent non-executive Directors are Mr. George William Hunter CAUTHERLEY, Mr. Michael James Connolly HOGAN, Mr. Ping Cho Terence HON and Mr. Dylan Carlo TINKER.

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