THIS SUPPLEMENTAL CIRCULAR IS IMPORTANT AND REQUIRES YOUR IMMEDIATE ATTENTION

If you are in doubt as to any aspect of this supplemental circular, you should consult your stockbroker or other registered dealer in securities, bank manager, solicitor, professional accountant or other professional adviser.

If you have sold or transferred all your shares in VISEN Pharmaceuticals 维贤药业(维贤藥業), you should at once hand this supplemental circular and the accompanying supplemental form of proxy to the purchaser or the transferee or to the bank, stockbroker or other agent through whom the sale or the transfer was effected for transmission to the purchaser or the transferee.

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

VISEN

VISEN PHARMACEUTICALS

维贤药业

(Incorporated in the Cayman Islands with limited liability)

(Stock Code: 2561)

SUPPLEMENTAL CIRCULAR

IN RELATION TO THE PROPOSED APPOINTMENT OF

DIRECTORS BY REQUISITION

AND

SUPPLEMENTAL NOTICE OF THE ANNUAL GENERAL MEETING

This supplemental circular should be read together with the circular of the Company and the Original Proxy Form dated 27 April 2026.

A supplemental notice convening the AGM of VISEN Pharmaceuticals 维贤药业(维贤藥業) to be held at Room 1701, 1788 Square, No. 1788 West Nanjing Road, Jing'an District, Shanghai, China on Friday, 26 June 2026 at 10:00 a.m. is set out in this supplemental circular. A supplemental form of proxy for use at the AGM is enclosed with this supplemental circular. Such supplemental form of proxy is also published on the websites of The Stock Exchange of Hong Kong Limited at www.hkex.com.hk and the Company at www.visenpharma.com.

Whether or not you are able to attend the AGM, you are requested to complete the accompanying the supplemental form of proxy in accordance with the instructions printed thereon and deposit the same at the Company's branch share registrar in Hong Kong, Computershare Hong Kong Investor Services Limited, at 17M Floor, Hopewell Centre, 183 Queen's Road East, Wanchai, Hong Kong as soon as possible and in any event not less than 48 hours before the time appointed for the holding of the AGM or any adjournment thereof. Completion and return of the Original Proxy Form and the Supplemental Proxy Form will not preclude you from attending and voting in person at the annual general meeting or any adjournment thereof should you so wish and in such event, the instrument appointing a proxy shall be deemed to be revoked. For the avoidance of doubt, holders of treasury shares of the Company, if any, shall abstain from voting at the AGM.

17 June 2026

CONTENTS

Page

DEFINITIONS... 1
LETTER FROM THE BOARD... 4
APPENDIX I – DETAILS OF THE DIRECTORS TO BE APPOINTED
AT THE ANNUAL GENERAL MEETING... 8
SUPPLEMENTAL NOTICE OF AGM... 12

• i -

DEFINITIONS

In this supplemental circular, unless the context otherwise requires, the following expressions shall have the following meanings:

"AGM" or "Annual General Meeting" the annual general meeting of the Company to be held at 1701, 1788 Square, No. 1788 West Nanjing Road, Jing'an District, Shanghai, China on Friday, 26 June 2026 at 10:00 a.m.

"Articles" or "Articles of Association" the articles of association of our Company conditionally adopted by a special resolutions passed on March 8, 2025 with effect from the Listing Date

"Ascendis Requisition Notice" a letter to the Company dated 9 June 2026, as amended and superseded by a notice to the Company dated 17 June 2026, from the Ascendis Requisitionists in respect of the Requisition

"Ascendis Requisitionist(s)" Ascendis Pharma Endocrinology Division A/S and Ascendis Pharma Bone Diseases A/S, being the registered shareholders of 33,423,296 Shares, on a one vote per share basis, in the share capital of the Company as at the date of the Ascendis Requisition Notice

"Board" the board of Directors

"Business day" any day (other than a Saturday, Sunday or public holiday in Hong Kong) on which banks in Hong Kong are generally open for normal banking business

"CCASS" The Central Clearing and Settlement System established and operated by the HKSCC

"China" or "the PRC" the People's Republic of China, and for the purposes of this documents only, except where the context requires otherwise, references to China or the PRC exclude the special administrative region of Hong Kong and Macau and Taiwan

"Circular" or "AGM Circular" the circular of the Company dated 27 April 2026

"Company" VISEN Pharmaceuticals, an exempted company with limited liability incorporated in the Cayman Islands on November 1, 2018, the Shares of which are listed on the Main Board of the Stock Exchange (stock code: 2561)

"Director(s)" the director(s) of the Company

• 1 -

DEFINITIONS

“Group,” “our Group,”
“the Group,” “we,”
“us,” or “our”
the Company and its subsidiaries from time to time, and where
the context requires, in respect of the period prior to our Company
becoming the holding company of its present subsidiaries, such
subsidiaries as if they were subsidiaries of our Company at the
relevant time

“HK$”
Hong Kong dollars, the lawful currency of Hong Kong

“Hong Kong”
the Hong Kong Special Administrative Region of the People’s
Republic of China

“Hong Kong Stock Exchange”
or “Stock Exchange”
The Stock Exchange of Hong Kong Limited

“Latest Practicable Date”
17 June 2026, being the latest practicable date prior to the
publication of this supplemental circular for ascertaining certain
information in this supplemental circular

“Listing Date”
21 March 2025, on which the Shares were listed on the Stock
Exchange and from which dealings in the Shares were permitted
to commence on the Stock Exchange

“Listing Rules”
the Rules Governing the Listing of Securities on the Stock
Exchange as amended from time to time

“Proposed Appointment”
the proposed appointment of the Proposed Directors

“Proposed Directors”
collectively, Mr. Roy Paul Khoury, Ms. Sherrie Lynn Glass and
Mr. Michael J. Chang

“Requisition”
the requisitions contained in the Requisition Notice relating to,
among others, the Proposed Appointment as referred to in this
supplemental circular

“Member(s)” or
“Shareholder(s)”
holder(s) of the Share(s)

“Original Proxy Form”
the form of proxy enclosed to the Circular

“RMB”
Renminbi, the lawful currency of the PRC

– 2 –

DEFINITIONS

"SFO"
the Securities and Futures Ordinance, Chapter 571 of the Laws of Hong Kong as amended, supplemented or otherwise modified from time to time

"Share(s)"
ordinary share(s) of USD0.0001 each in the issued capital of the Company or if there has been a subsequent sub-division, consolidation, reclassification or reconstruction of the share capital of the Company, shares forming part of the ordinary equity share capital of the Company (treasury shares, if any and registered under the name of the Company, shall have no voting rights at the general meeting(s) of the Company; and for the avoidance of doubt, solely from the perspective of the Listing Rules, the Company shall, upon depositing any treasury shares in the CCASS, abstain from voting at any of its general meeting(s) in relation to those shares)

"Shareholder(s)"
holder(s) of Share(s)

"Stock Exchange"
The Stock Exchange of Hong Kong Limited

"subsidiary" or "subsidiaries"
has the meaning as ascribed to it under the Listing Rules

"Substantial Shareholders"
has the meaning ascribed to it under the Listing Rules

"Supplemental AGM Notice"
the supplemental notice of AGM dated 17 June 2026

"Supplemental Proxy Form"
the supplemental form of proxy enclosed to this supplemental circular

"treasury shares"
has the meaning ascribed to it under the Listing Rules and as amended from time to time

"Vivo Requisition Notice"
a letter to the Company dated 16 June 2026 from the Vivo Requisitionists in respect of the Requisition

"Vivo Requisitionist(s)"
Vivo Plenilune IX Limited, being the shareholder of 37,167,064 Shares, on a one vote per share basis, in the share capital of the Company as at the date of the Vivo Requisition Notice

"%
per cent

• 3 -

LETTER FROM THE BOARD

VISEN

VISEN PHARMACEUTICALS

维昇药业

(Incorporated in the Cayman Islands with limited liability)

(Stock Code: 2561)

Executive Director:
Mr. LU An-Bang (盧安邦)

Non-executive Directors:
Mr. FU Shan (付山) (Chairman)
Mr. CAO Yibo (曹弋博)

Independent Non-executive Directors:
Dr. YAO Zhengbin (Bing)
Mr. CHAN Peng Kuan (陳炳鈞)
Ms. NI Hong (倪虹)
Mr. ZHANG Qing (張勋)

Registered Office:
Harbour Place 2nd Floor
PO Box 472
103 South Church Street
Grand Cayman
KY1-1106
Cayman Islands

Headquarter:
Suite 3-108, Floor 3, Building B
Hengtai Lixiang Chuangxin
Tower, 69 Jiuzhang Road
Suzhou
China

Principal Place of Business
in Hong Kong:
Room 1919, 19/F Lee Garden One
33 Hysan Avenue
Causeway Bay
Hong Kong

17 June 2026

To the Shareholders

Dear Sir or Madam,

SUPPLEMENTAL CIRCULAR
IN RELATION TO THE PROPOSED APPOINTMENT OF
DIRECTORS BY REQUISITION
AND
SUPPLEMENTAL NOTICE OF ANNUAL GENERAL MEETING

LETTER FROM THE BOARD

INTRODUCTION

This supplemental circular should be read together with the Circular which contains, among other things, information regarding the resolutions to be proposed at the AGM.

The purpose of this supplemental circular is to give you the Supplemental AGM Notice and the relevant information regarding the proposals to seek the approval of the Shareholders at AGM for the proposed resolutions set out in the Requisition Notice in relation to the Proposed Appointment.

REQUISITION BY THE REQUISITIONIST

On 17 June 2026, the Board received a proposal from Ascendis Requisitionists requesting the Board to put the following resolutions as ordinary resolutions at the AGM:

1. "THAT Mr. Roy Paul Khoury be and is hereby appointed as a non-executive Director with immediate effect."
2. "THAT Ms. Sherrie Lynn Glass be and is hereby appointed as a non-executive Director with immediate effect."

On 16 June 2026, the Board received a proposal from Vivo Requisitionist requesting the Board to put the following resolution as an ordinary resolution at the AGM:

"THAT Mr. Michael J. Chang be and is hereby appointed as a non-executive Director with immediate effect."

PROPOSED APPOINTMENT

The Requisitionists proposed to appoint the Proposed Directors with immediate effect upon passing the ordinary resolution(s) at the AGM. Pursuant to Rule 13.70 of the Listing Rules, upon nomination of director by its shareholders, the issuer shall include particulars of the proposed director in the announcement or supplementary circular and must give shareholders at least seven days to consider the relevant information disclosed in such an announcement or supplementary circular prior to the date of the meeting of the election. The Company is required to disclose the details referred to Rule 13.51(2) of the Listing Rules in respect of any proposed new director in the notice or accompanying circular to its shareholders of the relevant general meeting. Biographical details of the Proposed Directors were provided by Ascendis Requisitionists and Vivo Requisitionists in Ascendis Requisition Notice and Vivo Requisition Notice, respectively, and are reproduced in the Appendix I to this Supplemental Circular.

LETTER FROM THE BOARD

INFORMATION ON THE REQUISITIONISTS

Ascendis Requisitionists, being Ascendis Pharma Endocrinology Division A/S and Ascendis Pharma Bone Diseases A/S, were the registered shareholders of an aggregate of 33,423,296 Shares, representing approximately 29.34% of the entire issued share capital of the Company as at the date of Ascendis Requisition Notice.

Vivo Requisitionists, being Vivo Plenilune IX Limited, was the shareholder of an aggregate of 37,167,064 Shares, representing approximately 32.62% of the entire issued share capital of the Company as at the date of Vivo Requisition Notice.

AGM

A supplemental notice in respect of the AGM to be held as originally scheduled at Room 1701, 1788 Square, No. 1788 West Nanjing Road, Jing'an District, Shanghai, China on Friday, 26 June 2026 at 10:00 a.m. is being despatched to the Shareholders together with this supplemental circular.

Save as disclosed in this supplemental circular, please refer to the AGM Circular and AGM Notice for details of the ordinary resolutions numbers 1 to 6 to be proposed at the AGM, eligibility for attending the AGM, appointment of proxy, registration procedures, closure of register of members and other relevant matters.

Having made all reasonable enquiries, to the best of the knowledge, information and belief of the Directors, as at the Latest Practicable Date, no Shareholder is required to abstain from voting on the resolutions to be proposed at the AGM.

PROXY ARRANGEMENT

The Supplemental Proxy Form for use at the AGM is enclosed with this supplemental circular. The Supplement Proxy Form is to be used for the supplemental resolution set out in the supplemental notice of AGM and will not affect the validity of duly completed Original Proxy Form in respect of the resolutions set out in the AGM Notice included in the AGM Circular. Shareholders who intend to appoint a proxy to attend the AGM and vote on the resolutions set out in the supplemental notice of AGM shall complete and return the Supplemental Proxy Form in accordance with the instructions printed thereon. For the avoidance of doubt, if you have completed and returned the Original Proxy Form in accordance with the instructions printed thereon but have not completed and returned the Supplemental Proxy Form, such shareholder's proxy will be entitled to vote on behalf of the shareholder in his/her discretion on the resolutions set out in the Supplemental Proxy Form. If you have completed and returned the Supplemental Proxy Form in accordance with the instructions printed thereon but have not completed and returned the Original Proxy Form, such shareholder's proxy will be entitled to vote on behalf of the shareholder in his/her discretion on the resolutions set out in the Original Proxy Form. Completion and return of the Original Proxy Form and/or the Supplemental Proxy Form will not preclude you from attending and voting at the AGM, or any adjournment thereof should you so wish.

LETTER FROM THE BOARD

Shareholders who intend to appoint a proxy to attend the AGM and to vote on the resolutions set out in the Original AGM Notice and/or the Supplemental AGM Notice are requested to complete and return the Original Proxy Form and/or Supplemental Proxy Form in accordance with the instructions printed thereon not less than 48 hours before the time appointed for the holding of the AGM or any adjournment thereof (as the case may be). Completion and return of the Original Proxy Form and/or Supplemental Proxy Form will not prevent you from attending and voting in person at the AGM or any adjournment thereof if you so wish.

RESPONSIBILITY STATEMENT

This supplemental circular, for which the Directors collectively and individually accept full responsibility, includes particulars given in compliance with the Listing Rules for the purpose of giving information with regard to the Company. The Directors, having made all reasonable enquiries, confirm that to the best of their knowledge and belief the information contained in this supplemental circular is accurate and complete in all material respects and not misleading or deceptive, and there are no other matters the omission of which would make any statement herein or this supplemental circular misleading.

RECOMMENDATION

The Directors consider that the resolutions set out in this supplemental circular to be proposed at the AGM is in the interests of the Company and the Shareholders as a whole. Accordingly, the Directors recommend the Shareholders to vote in favour of these proposed resolutions.

GENERAL

To the best of the Directors' knowledge, information and belief, having made all reasonable enquiries, no Shareholder is required to abstain from voting on any resolutions to be proposed at the AGM.

Your attention is drawn to the information set out in the appendices to this supplemental circular. The English text of this supplemental circular shall prevail over the Chinese text for the purpose of interpretation.

Yours faithfully

For and on behalf of the Board

VISEN Pharmaceuticals

Mr. LU An-Bang

Executive Director and Chief Executive Officer

APPENDIX I DETAILS OF THE DIRECTORS TO BE APPOINTED AT THE ANNUAL GENERAL MEETING

NON-EXECUTIVE DIRECTORS

Mr. Roy Paul Khoury (“Mr. Khoury”)

Mr. Khoury, aged 52, has over 20 years of experience in the pharmaceutical and healthcare industry, particularly in marketing, strategy and portfolio management.

Mr. Khoury started his career as an account supervisor in the medical marketing group at ApotheCom Scopemedical Limited, serving Pharmacia Corporation (later acquired by Pfizer Inc., a company listed on the New York Stock Exchange (stock code: PFE)) from September 2001 to September 2003. He subsequently joined Novartis AG, a company listed on the New York Stock Exchange (stock code: NVS), where he worked from September 2003 to June 2008 and held various senior positions, including Global Head of Medical Marketing (Urology).

From June 2008 to July 2015, Mr. Khoury held senior roles at Allergan Pharmaceuticals (AGN) (now part of AbbVie Inc., a company listed on the New York Stock Exchange (stock code: ABBV)), including Senior Director of Marketing for EMEA (Neurosciences & Urology), and Vice President of Global Commercial Operations (ex-US), covering medical aesthetics, ophthalmology, neurosciences and urology.

In August 2015, Mr. Khoury founded RPK & Associates, a healthcare consultancy, and served as its founder until June 2016. He then joined Livallova PLC, a company listed on NASDAQ (stock code: LVN) in June 2016, where he served until April 2022. During his tenure, he held senior leadership positions, including Executive Director, Senior Vice President of Global Portfolio Strategy and President of International Markets. Following his departure from Livallova PLC, Mr. Khoury re-joined RPK & Associates in April 2022 and served as its founder until June 2023.

Since June 2023, Mr. Khoury has been employed at Ascendis Pharma A/S, a company whose shares are listed on the Nasdaq Global Select Market in New York (stock code: ASND). He served as Vice President and Head of International Markets, responsible for international markets and partner and alliance management, with a focus on the endocrinology portfolio.

Mr. Khoury obtained an associate degree in Business Administration at LaSalle College, Canada in June 1996.

Save as disclosed above, Mr. Khoury did not hold any directorship in any public companies, the securities of which are listed on any securities market in Hong Kong or overseas in the last three years.

As at the date hereof, Mr. Khoury serves as Vice President & Head of International Markets of Ascendis Pharma A/S, which (through its wholly-owned subsidiaries) holds more than 30% of the issued share capital of the Company and is therefore a controlling shareholder of the Company. Mr. Khoury does not have any relationship with any other Directors, senior management or substantial Shareholders or controlling Shareholders.

APPENDIX I

DETAILS OF THE DIRECTORS TO BE APPOINTED AT THE ANNUAL GENERAL MEETING

Mr. Khoury will enter into a service contract or letter of appointment with the Company. Mr. Khoury will not receive any emoluments in connection with his directorship as a non-executive director of the Company. He is subject to retirement by rotation and re-election at general meetings of the Company in accordance with the articles of association of the Company and the Listing Rules.

As at the Latest Practicable Date, Mr. Khoury had no other interest in the Shares or underlying Shares within the meaning of Part XV of the SFO.

There is no information which is disclosable nor is Mr. Khoury involved in any of the matters required to be disclosed pursuant to any of the requirements under Rule 13.51(2)(h) to (v) of the Listing Rules and there are no other matters concerning Mr. Khoury that need to be brought to the attention of the Shareholders.

Ms. Sherrie Lynn Glass ("Ms. Glass")

Ms. Glass, aged 54, has over 25 years of experience in the pharmaceutical and healthcare industry, particularly in strategy, business development and commercial operations.

Ms. Glass started her career at Monitor Group Consulting (now part of Deloitte), where she served as Associate Partner and Global Account Manager in the Life Sciences Practice from September 1998 to January 2011, leading consulting engagements for global biopharmaceutical companies on topics of commercialisation and strategy.

From February 2011 to November 2015, Ms. Glass served as Principal and Partner in the Biopharma Practice at Boston Consulting Group (BCG), leading consulting engagements for global biopharmaceutical companies on strategy, commercialisation and company transformation.

From November 2015 to May 2021, Ms. Glass held senior positions at Allergan plc (which was subsequently acquired by AbbVie Inc. in May 2020, a company listed on the New York Stock Exchange (stock code: ABBV)), including Vice President, Corporate Initiatives and Integration (November 2015 to December 2018), where she led the integration into Allergan plc of all acquisitions, including several multi-billion dollar acquisitions, managed all divestitures and major corporate transformations; and Vice President, Managed Markets Pipeline Access and Strategy (December 2018 to May 2021), where she led efforts to prepare late-stage and launch pipeline products for successful U.S. market access, with a focus on migraine programmes.

• 9 -

APPENDIX I DETAILS OF THE DIRECTORS TO BE APPOINTED AT THE ANNUAL GENERAL MEETING

From May 2021 to March 2024, Ms. Glass served as Senior Vice President, Enterprise Strategy at Bristol-Myers Squibb Company, a company listed on the New York Stock Exchange (stock code: BMY), where she led the company's strategic planning with its board of directors, oversaw mid-to-late stage R&D portfolio prioritisation to maximise long-term value and growth, and drove mergers and acquisitions and business development assessments to identify acquisition targets.

Since September 2024, Ms. Glass has been employed at Ascendis Pharma A/S, a company whose shares are listed on the Nasdaq Global Select Market in New York (stock code: ASND), where she serves as Chief Business Officer and is a member of the Executive Team. In this role, she leads Strategy, Business Development, Alliance Management, and Global Forecasting and Business Insights, and is responsible for tracking overall company performance versus goals and development of growth strategy.

Ms. Glass obtained a Bachelor of Arts degree (with Honours: Magna Cum Laude; Phi Beta Kappa) in History and Religious Studies from Brown University, Providence, Rhode Island, United States in 1993. She subsequently obtained a Master of Public and International Affairs in International Relations from Princeton University, Princeton, New Jersey, United States in 1998.

Save as disclosed above, Ms. Glass did not hold any directorship in any public companies, the securities of which are listed on any securities market in Hong Kong or overseas in the last three years.

As at the date hereof, Ms. Glass serves as Chief Business Officer of Ascendis Pharma A/S, which (through its wholly-owned subsidiaries) holds more than 30% of the issued share capital of the Company and is therefore a controlling shareholder of the Company. Ms. Glass does not have any relationship with any other Directors, senior management or substantial Shareholders or controlling Shareholders.

Ms. Glass will enter into a service contract or letter of appointment with the Company. Ms. Glass will not receive any emoluments in connection with her directorship as a non-executive director of the Company. She is subject to retirement by rotation and re-election at general meetings of the Company in accordance with the articles of association of the Company and the Listing Rules.

As at the Latest Practicable Date, Ms. Glass had no other interest in the Shares or underlying Shares within the meaning of Part XV of the SFO.

There is no information which is disclosable nor is Ms. Glass involved in any of the matters required to be disclosed pursuant to any of the requirements under Rule 13.51(2)(h) to (v) of the Listing Rules and there are no other matters concerning Ms. Glass that need to be brought to the attention of the Shareholders.

• 10 -

APPENDIX I

DETAILS OF THE DIRECTORS TO BE APPOINTED AT THE ANNUAL GENERAL MEETING

Mr. Michael J. Chang ("Mr. Chang")

Mr. Chang, aged 43, worked in Vivo Capital LLC since August 2012 and now is a managing partner of Vivo Capital LLC. Prior to joining Vivo Capital, Mr. Chang worked at Johnson & Johnson, a company listed on NYSE (stock code: JNJ), serving as a senior manager from August 2008 to September 2010 and a part-time consultant in 2011. From August 2006 to July 2008, Mr. Chang served as a consultant in Strategy & (formerly known as Booz & Company Inc.). Prior to that, Mr. Chang worked as an analyst in the healthcare team of Fletcher Spaght Inc. from July 2005 to May 2006. Mr. Chang was a non-executive director of the Company for the period from 1 December 2023 to 27 August 2025.

Mr. Chang obtained his Bachelor's degree in Economics from Harvard College in 2005, and obtained an M.B.A. from Harvard Business School in 2012.

Save as disclosed above, Mr. Chang did not hold any directorship in any public companies, the securities of which are listed on any securities market in Hong Kong or overseas in the last three years.

As at the date hereof, Mr. Chang serves as managing partner of Vivo Capital LLC. Vivo Plenilune IX Limited ("Vivo Capital") is a company established under the Laws of Cayman Islands, which holds more than 30% of the issued share capital of the Company and is therefore a controlling shareholder of the Company. Vivo Capital is a wholly-owned subsidiary of Vivo Capital Fund IX (Cayman), L.P., which is in turn controlled by its general partner, Vivo Capital IX (Cayman), LLC. (collectively, "Vivo Funds"). Vivo Funds are under the management of Vivo Capital LLC. Mr. Chang does not have any relationship with any other Directors, senior management or substantial Shareholders or controlling Shareholders.

Mr. Chang will enter into a service contract or letter of appointment with the Company. Mr. Chang will not receive any emoluments in connection with his directorship as a non-executive director of the Company. He is subject to retirement by rotation and re-election at general meetings of the Company in accordance with the articles of association of the Company and the Listing Rules.

As at the Latest Practicable Date, Mr. Chang had no other interest in the Shares or underlying Shares within the meaning of Part XV of the SFO.

There is no information which is disclosable nor is Mr. Chang involved in any of the matters required to be disclosed pursuant to any of the requirements under Rule 13.51(2)(h) to (v) of the Listing Rules and there are no other matters concerning Mr. Chang that need to be brought to the attention of the Shareholders.

SUPPLEMENTAL NOTICE OF AGM

VISEN

VISEN PHARMACEUTICALS

维昇药业

(Incorporated in the Cayman Islands with limited liability)

(Stock Code: 2561)

SUPPLEMENTAL NOTICE OF ANNUAL GENERAL MEETING

Reference is made to the notice (the "Original Notice") of the annual general meeting (the "AGM") of VISEN Pharmaceuticals (the "Company") dated 27 April 2026. This supplemental notice (the "Supplemental Notice") should be read together with the Original Notice.

SUPPLEMENTAL NOTICE IS HEREBY GIVEN that the annual general meeting will be held at Room 1701, 1788 Square, No. 1788 West Nanjing Road, Jing'an District, Shanghai, China on Friday, 26 June 2026 at 10:00 a.m. as scheduled. Terms used in this supplemental notice shall have the same meanings as those defined in the supplemental circular of the Company dated 17 June 2026 (the "Supplemental Circular") unless otherwise specified.

In addition to the resolutions set out in the Original Notice, the following additional resolutions will be considered and, if thought fit, to be approved at the AGM:

ORDINARY RESOLUTIONS

2(e). To appoint Mr. Roy Paul Khoury as a non-executive director of the Company;

2(f). To appoint Ms. Sherrie Lynn Glass as a non-executive director of the Company.

2(g). To appoint Mr. Michael J. Chang as a non-executive director of the Company.

For details of the above new resolutions, please refer to the Supplemental Circular of the Company dated 17 June 2026.

This Supplemental Notice should be read in conjunction with the Original Notice. Apart from the amendments set out above, all the information contained in the Original Notice shall remain to have full force and effect.

By order of the Board

VISEN Pharmaceuticals

Mr. LU An-Bang

Executive Director and Chief Executive Officer

Hong Kong, 17 June 2026

SUPPLEMENTAL NOTICE OF AGM

Notes:

1. Details of the above resolutions are set out in the supplemental circular dated 17 June 2026 of the Company. Please refer to the AGM Circular for details of other resolutions to be proposed at the AGM.

2. As the proxy form published by the Company on the websites of the Stock Exchange (www.hkexnews.hk) and the Company (www.visenpharma.com) on 27 April 2026 (the “Original Proxy Form”) does not contain the newly added resolutions set out in this supplemental notice, a revised proxy form containing the above newly added resolutions (the “Supplemental Proxy Form”) has been prepared and is enclosed in this Supplemental Notice.

3. The Supplemental Proxy Form for use at the AGM is enclosed with the supplemental circular. The Supplemental Proxy Form is to be used for the supplemental resolution set out in the supplemental notice of AGM and will not affect the validity of duly completed Original Proxy Form in respect of the resolutions set out in the AGM Notice included in the AGM Circular. Shareholders who intend to appoint a proxy to attend the AGM and vote on the resolution set out in the supplemental notice of AGM shall complete and return the Supplemental Proxy Form in accordance with the instructions printed thereon. For the avoidance of doubt, if you have completed and returned the Original Proxy Form in accordance with the instructions printed thereon but have not completed and returned the Supplemental Proxy Form, such shareholder’s proxy will be entitled to vote on behalf of the shareholder in his/her discretion on the resolution set out in the Supplemental Proxy Form. If you have completed and returned the Supplemental Proxy Form in accordance with the instructions printed thereon but have not completed and returned the Original Proxy Form, such shareholder’s proxy will be entitled to vote on behalf of the shareholder in his/her discretion on the resolutions set out in the Original Proxy Form. Completion and return of the Original Proxy Form and/or the Supplemental Proxy Form will not preclude you from attending and voting at the AGM, or any adjournment thereof should you so wish.

Shareholders who intend to appoint a proxy to attend the AGM and to vote on the resolutions set out in the Original AGM Notice and/or the Supplemental AGM Notice are requested to complete and return the Original Proxy Form and/or Supplemental Proxy Form in accordance with the instructions printed thereon not less than 48 hours before the time appointed for the holding of the AGM or any adjournment thereof (as the case may be). Completion and return of the Original Proxy Form and/or Supplemental Proxy Form will not prevent you from attending and voting in person at the AGM or any adjournment thereof if you so wish.

1. In order to be valid, the supplemental form of proxy must be deposited together with a power of attorney or other authority, if any, under which it is signed or a notarially certified copy of that power or authority, at the offices of the Company’s branch 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 before the time for holding the meeting or adjourned meeting (as the case may be).

2. Please pay attention that completion and delivery of the Original Proxy Form and/or the Supplemental Proxy Form will not preclude you from attending and voting at the AGM if you so wish. In such event, the instrument for appointing a proxy shall be deemed to be revoked.

3. The above resolution will be put to vote at the AGM by way of poll.

As at the date of this notice, the Board comprises (i) Mr. LU An-Bang as executive director; (ii) Mr. FU Shan and Mr. CAO Yibo as non-executive directors; and (iii) Dr. YAO Zhengbin (Bing), Mr. CHAN Peng Kuan, Ms. NI Hong and Mr. ZHANG Qing as independent non-executive directors.

• 13 -

SUPPLEMENTAL NOTICE OF AGM

This supplemental circular (in both English and Chinese versions) has been posted on the Company’s website at www.visenpharma.com.

Shareholders may request for printed copy of the circular free of charge or change their choice of means of receipt and language of the Company’s corporate communications by sending reasonable notice in writing to the Company’s branch registrar in Hong Kong, Computershare Hong Kong Investor Services Limited, at 17M Floor, Hopewell Centre, 183 Queen’s Road East, Wanchai, Hong Kong or by sending an email to [email protected].

Shareholders who have chosen to receive the Company’s corporate communications in either English or Chinese version will receive both English and Chinese versions of this circular since both languages are bound together into one booklet.

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