Zai Lab Limited — Proxy Solicitation & Information Statement 2026

Apr 28, 2026

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.

Zai Lab Limited

再鼎醫藥有限公司*

(Incorporated in the Cayman Islands with limited liability)

(Stock Code: 9688)

NOTICE OF ANNUAL GENERAL MEETING OF SHAREHOLDERS

Notice is hereby given with respect to the 2026 annual general meeting of shareholders (the “Annual Meeting”) of Zai Lab Limited (the “Company”).

Time and date: 8:00 a.m. (U.S. Eastern Time) on Wednesday, June 17, 2026 / 8:00 p.m. (Shanghai and Hong Kong Time) on Wednesday, June 17, 2026

Physical location: 899 Halei Road, Building B, Pudong, Shanghai, China 201203

Virtual meeting site: www.virtualshareholdermeeting.com/ZLAB2026

Record date: Thursday, April 16, 2026 (the “Record Date”)

Latest time to lodge transfer documents for registration with the Company's Hong Kong Share Registrar and Transfer Agent: At 4:30 p.m. (Shanghai and Hong Kong Time) on Thursday, April 16, 2026

Purpose of the Annual Meeting: The purpose of the meeting is to consider and vote on the following matters:

1. An ordinary resolution to re-elect Samantha (Ying) Du to serve as a director until the 2027 annual general meeting of shareholders and until her successor is duly elected and qualified, subject to her earlier resignation or removal;

2. An ordinary resolution to re-elect John D. Diekman to serve as a director until the 2027 annual general meeting of shareholders and until his successor is duly elected and qualified, subject to his earlier resignation or removal;

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1. An ordinary resolution to re-elect Richard Gaynor to serve as a director until the 2027 annual general meeting of shareholders and until his successor is duly elected and qualified, subject to his earlier resignation or removal;

2. An ordinary resolution to re-elect Nisa Leung to serve as a director until the 2027 annual general meeting of shareholders and until her successor is duly elected and qualified, subject to her earlier resignation or removal;

3. An ordinary resolution to re-elect William Lis to serve as a director until the 2027 annual general meeting of shareholders and until his successor is duly elected and qualified, subject to his earlier resignation or removal;

4. An ordinary resolution to re-elect Scott Morrison to serve as a director until the 2027 annual general meeting of shareholders and until his successor is duly elected and qualified, subject to his earlier resignation or removal;

5. An ordinary resolution to re-elect Leon O. Moulder Jr. to serve as a director until the 2027 annual general meeting of shareholders and until his successor is duly elected and qualified, subject to his earlier resignation or removal;

6. An ordinary resolution to re-elect Michel Vounatsos to serve as a director until the 2027 annual general meeting of shareholders and until his successor is duly elected and qualified, subject to his earlier resignation or removal;

7. An ordinary resolution to re-elect Peter Wirth to serve as a director until the 2027 annual general meeting of shareholders and until his successor is duly elected and qualified, subject to his earlier resignation or removal;

8. An ordinary resolution to approve the appointment of KPMG LLP and KPMG as the Company’s independent registered public accounting firms and auditors to audit our consolidated financial statements to be filed with the U.S. Securities and Exchange Commission and The Stock Exchange of Hong Kong Limited (the “Stock Exchange”) for the year ending December 31, 2026, respectively;

9. An ordinary resolution to authorize the board of directors of the Company (the “Board of Directors”) to fix auditor compensation for 2026;

10. An ordinary resolution to approve, on an advisory basis, the compensation of our named executive officers, as disclosed in the Company’s proxy statement for the Annual Meeting dated April 28, 2026 (the “Proxy Statement”);

11. An ordinary resolution to approve a general mandate to the Board of Directors to allot and issue ordinary shares and/or American Depositary Shares (“ADSs”) and/or resell treasury shares of up to 10% of the total number of issued ordinary shares of the Company (excluding treasury

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shares) as of the date of the Annual Meeting until the 2027 annual general meeting of shareholders;

1. An ordinary resolution to approve a general mandate to repurchase ordinary shares and/or ADSs of up to 10% of the total number of issued ordinary shares of the Company (excluding treasury shares) as of the date of the Annual Meeting until the 2027 annual general meeting of shareholders; and

2. To transact such other business as may properly come before the Annual Meeting and any adjournment or postponement thereof.

Further details of the proposals above are set out in the Proxy Statement. You can review and download the Proxy Statement, in English and Chinese, from the Company's website and the website of the Stock Exchange.

How to attend the Annual Meeting:

If you are a shareholder of record of our ordinary shares, you may attend the Annual Meeting in person at 899 Halei Road, Building B, Pudong, Shanghai, China 201203, or virtually by visiting our Annual Meeting website at www.virtualshareholdermeeting.com/ZLAB2026. To participate in the Annual Meeting, you will need the 16-digit control number included on your proxy card or instructions that accompanied your proxy materials. Shareholders are encouraged to log in to this website and pre-register for the Annual Meeting before the start time of the meeting. Online check-in will begin 15 minutes prior to the start of the meeting, and you should allow ample time for the online check-in procedures. If you choose to attend the Annual Meeting virtually, there will be technicians ready to assist you with any technical difficulties you may have accessing the virtual meeting website. If you encounter any difficulties accessing the virtual meeting website during the check-in or meeting time, please call the technical support number that will be posted on the Annual Meeting log-in page. Holders of ADSs will not be entitled to attend or vote at the Annual Meeting.

How to vote — Registered shareholders on our Hong Kong share register or Cayman Islands share register:

If you are a shareholder of record of our ordinary shares registered on our Hong Kong register or Cayman Islands register as of the Record Date, you may vote at the Annual Meeting, in person or virtually, through the Internet in advance of the Annual Meeting, or by proxy using a proxy card. Whether or not you plan to attend the Annual Meeting, we urge you to vote by proxy to help ensure your vote is counted. You may still attend the meeting and vote even if you have already voted by proxy; such appointment of proxy will be revoked if you attend and vote at the Annual Meeting.

• Mail: If you received your proxy materials by mail, simply complete, sign, and date the proxy card that you received and return it promptly in the prepaid envelope provided or return it to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717. Proxy cards submitted by mail must be received no later than 11:59 a.m. (U.S. Eastern Time) / 11:59 p.m. (Shanghai and Hong Kong Time) on June 16, 2026, to be voted at the Annual Meeting.

• Internet: To vote through the Internet, go to www.proxyvote.com to complete an electronic voting instruction form. You will be asked to

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provide the 16-digit control number included on your proxy card or on the instructions that accompanied your proxy materials. Your Internet vote must be received by 11:59 p.m. on June 14, 2026 (U.S. Eastern Time) / 11:59 a.m. on June 15, 2026 (Shanghai and Hong Kong Time) to be counted.

• Virtually: To vote while virtually attending the Annual Meeting, attend the meeting by visiting www.virtualshareholdermeeting.com/ZLAB2026. You will be asked to provide the 16-digit control number included on your proxy card or on the instructions that accompanied your proxy materials.
• In Person: To vote in person at the Annual Meeting, attend the meeting by going to 899 Halei Road, Building B, Pudong, Shanghai, China 201203.

How to vote — Beneficial shareholders holding shares by nominees:

If you are a beneficial owner of ordinary shares registered on the Record Date in the name of a brokerage firm, bank, or other financial institution, you should have received information containing voting instructions from that organization rather than from us. Simply follow the voting instructions to help ensure that your vote is counted. To vote at the Annual Meeting, you must obtain a legal proxy or broker’s proxy card from your broker, bank, or other agent. Follow the instructions from your broker or bank included with these proxy materials or contact your broker or bank to request a proxy form.

By order of the Board

Zai Lab Limited

Samantha Du

Director, Chairperson and Chief Executive Officer

Hong Kong, April 28, 2026

As at the date of this notice, the board of directors of the Company comprises Dr. Samantha Du and Mr. Leon O. Moulder, Jr. as directors, and Dr. John Diekman, Dr. Richard Gaynor, Ms. Nisa Leung, Mr. William Lis, Mr. Scott W. Morrison, Mr. Michel Vounatsos and Mr. Peter Wirth as independent directors.

• For identification only