SinoMab BioScience Limited — Proxy Solicitation & Information Statement 2026

Apr 27, 2026

SINOMAB

SinoMab BioScience Limited

中國抗體製藥有限公司

(Incorporated in Hong Kong with limited liability)

(Stock code: 3681)

Number of shares to which this form of proxy relates (Note 1)

FORM OF PROXY FOR THE ANNUAL GENERAL MEETING TO BE HELD AT ROOM 3, 14/F, FAIRMONT HOUSE, 8 COTTON TREE DRIVE, CENTRAL, HONG KONG ON FRIDAY, 12 JUNE 2026 AT 10:00 A.M.

I/We (Note 2)

of

being the registered holder(s) of shares in the issued share capital of SinoMab BioScience Limited (the "Company") HEREBY APPOINT the Chairman of the meeting (Note 3) or

of

as my/our proxy to attend, act and vote for me/us and on my/our behalf as directed below at the annual general meeting (the "AGM") of the Company for the year 2026 to be held at Room 3, 14/F, Fairmont House, 8 Cotton Tree Drive, Central, Hong Kong on Friday, 12 June 2026 at 10:00 a.m. (and at any adjournment thereof).

Please tick (✓) the appropriate boxes to indicate how you wish your vote(s) to be cast (Note 4).

ORDINARY RESOLUTIONS		FOR	AGAINST
1.	To receive the audited consolidated financial statements of the Company and its subsidiaries and the reports of the directors and auditor for the year ended 31 December 2025.
2(a).	To re-elect Dr. Chi Ming LEE as an independent non-executive director of the Company.
2(b).	To re-elect Dr. Jianmin ZHANG as a non-executive director of the Company.
2(c).	To re-elect Ms. Chi Sau Giselle LEE as an independent non-executive director of the Company.
2(d)	To re-elect Mr. Nan SHEN as an independent non-executive director of the Company.
2(e).	To authorise the board of directors to fix the respective directors' remuneration.
2(f)	To elect Ms. Lei XUE as a non-executive director of the Company, with effect from the date of 2026 AGM for an initial term of three years, and to authorise the board of directors of the Company to fix her remuneration and to enter into a letter of appointment with her.
3.	To re-appoint Ernst & Young as auditor of the Company and to authorise the board of directors to fix its remuneration.
4.	To give a general mandate to the directors of the Company to buy back shares of the Company not exceeding 10% of the total number of issued shares of the Company as at the date of the passing of this resolution.
5.	To give a general mandate to the directors of the Company to issue, allot and deal with additional shares of the Company not exceeding 20% of the total number of issued shares of the Company as at the date of the passing of this resolution.
6.	To extend the general mandate granted to the directors of the Company to issue, allot and deal with additional shares in the capital of the Company by the aggregate number of the shares bought back by the Company under the general mandate in Resolution (4).

Date: __ day of __ 2026

Signature(s) (Note 5)

Notes:

1. Please insert the number of shares to which this form of proxy relates. If no number is inserted, this form of proxy will be deemed to relate to all the shares of the Company registered in your name(s). If more than one proxy is appointed, the number of shares in respect of which each such proxy so appointed must be specified.

2. Full name(s) and address(es) to be inserted in BLOCK CAPITALS. The names of all joint registered holders should be stated.

3. If any proxy other than the Chairman of the meeting is preferred, please strike out the words "the Chairman of the meeting" and insert the name and address of the proxy desired in the space provided. Any shareholder of the Company entitled to attend and vote at the AGM is entitled to appoint more than one proxy to attend and vote instead of him. A proxy need not be a shareholder of the Company. Every shareholder present in person or by proxy shall be entitled to one vote for each share held by him.

4. IMPORTANT: IF YOU WISH TO VOTE FOR A RESOLUTION, PLEASE TICK (✓) THE BOX MARKED "FOR". IF YOU WISH TO VOTE AGAINST A RESOLUTION, PLEASE TICK (✓) THE BOX MARKED "AGAINST". If no direction is given, your proxy will vote or abstain at his discretion. Your proxy will also be entitled to vote at his discretion on any resolution properly put to the AGM other than those referred to in the notice convening the AGM.

5. This form of proxy must be signed by you or your attorney duly authorised in writing. In case of a corporation, the same must be either under its seal or under the hand of a duly authorised officer. ANY ALTERATION MADE TO THIS FORM OF PROXY MUST BE INITIALLED BY THE PERSON WHO SIGNS IT.

6. In case of joint holders, the vote of the senior who tenders a vote, whether in person or by proxy, will be accepted to the exclusion of votes of the other joint holder(s) and for this purpose seniority will be determined by the order in which the names stand in the register of members of the Company.

7. In order to be valid, this form of proxy 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 or the adjourned meeting (as the case may be) (i.e. not later than 10:00 a.m. on Wednesday, 10 June 2026 (Hong Kong time)).

8. Completion and delivery of the form of proxy will not preclude you from attending and voting in person at the AGM or poll concerned if you so wish. In such event, this form of proxy shall be deemed to be revoked.

9. References to time and dates in this form of proxy are to Hong Kong time and dates.

PERSONAL INFORMATION COLLECTION STATEMENT

Your supply of your and your proxy's (or proxies') name(s) and address(es) is on a voluntary basis for the purpose of processing your request for the appointment of a proxy (or proxies) and your voting instructions for the AGM of the Company (the 'Purposes'). We may transfer your and your proxy's (or proxies') name(s) and address(es) to our agent, contractor, or third party service provider who provides administrative, computer and other services to us for use in connection with the Purposes and to such parties who are authorised by law to request the information or are otherwise relevant for the Purposes and need to receive the information. Your and your proxy's (or proxies') name(s) and address(es) will be retained for such period as may be necessary to fulfil the Purposes. Request for access to and/or correction of the relevant personal data can be made in accordance with the provisions of the Personal Data (Privacy) Ordinance and any such request should be in writing by the following means:

By mail to: Personal Data Privacy Officer

Computershare Hong Kong Investor Services Limited

17M Floor, Hopewell Centre, 183 Queen's Road East, Wanchai, Hong Kong

Or By email to: hkinfo@computershare.com.hk

This document is made in English and Chinese. In case of any inconsistency, the English version shall prevail.