Mabpharm Limited — Capital/Financing Update 2019

May 20, 2019

Unless otherwise defined herein, capitalized terms used in this announcement shall have the same meanings as those defined in the prospectus dated Monday, May 20, 2019 (the “ Prospectus ”) of Mabpharm Limited (the “ Company ”).

Hong Kong Exchanges and Clearing Limited, The Stock Exchange of Hong Kong Limited (the “ Stock Exchange ”) and Hong Kong Securities Clearing Company Limited (“ HKSCC ”) 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.

This announcement is for information purposes only and does not constitute an offer or an invitation to acquire, purchase or subscribe for any securities. Potential investors should read the Prospectus for detailed information about the Company and the Global Offering described below before deciding whether or not to invest in the Offer Shares.

This announcement is not for release, publication, distribution, directly or indirectly, in or into the United States or any other jurisdiction where such distribution is prohibited by law. This announcement does not constitute and is not an offer to sell or a solicitation of any offer to purchase or subscribe for securities in Hong Kong, the United States or elsewhere. The Offer Shares have not been and will not be registered under the United States Securities Act of 1933 (the “ U.S. Securities Act ”) or any state securities laws of the United States and may not be offered or sold within the United States except pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the U.S. Securities Act. There will be no public offering of securities of the Company in the United States.

In connection with the Global Offering, China International Capital Corporation Hong Kong Securities Limited, as stabilizing manager (the “ Stabilizing Manager ”), its affiliates or any person acting for it, on behalf of the Underwriters, may over-allocate Shares or effect transactions with a view to stabilizing or maintaining the market price of the Shares at a level higher than that which might otherwise prevail for a limited period after the Listing Date. However, there is no obligation on the Stabilizing Manager, its affiliates or any person acting for it, to conduct any such stabilizing action. Such stabilizing action, if taken, (a) will be conducted at the absolute discretion of the Stabilizing Manager (or any person acting for it) and in what the Stabilizing Manager reasonably regards as the best interest of the Company, (b) may be discontinued at any time and (c) is required to be brought to an end within 30 days of the last day for lodging applications under the Hong Kong Public Offering. Such stabilization action, if taken, may be effected in all jurisdictions where it is permissible to do so, in each case in compliance with all applicable laws, rules and regulatory requirements, including the Securities and Futures (Price Stabilizing) Rules, as amended, made under the Securities and Futures Ordinance (Cap. 571 of the Laws of Hong Kong).

Potential investors should be aware that stabilizing action cannot be taken to support the price of the Shares for longer than the stabilization period which begins on the Listing Date and is expected to expire on the 30th day after the last day for the lodging of the applications under the Hong Kong Public Offering. After this date, when no further stabilizing action may be taken, demand for the Shares, and therefore the price of the Shares, could fall.

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Mabpharm Limited 邁博葯業有限公司

(Incorporated in the Cayman Islands with limited liability)

GLOBAL OFFERING

Number of Offer Shares under the Global: 783,580,000 Shares (subject to the Over-allotment Offering Option) Number of Hong Kong Offer Shares: 78,358,000 Shares (subject to adjustment) Number of International Offer Shares: 705,222,000 Shares (subject to adjustment and the Over-allotment Option) Offer Price (subject to a: HK$1.50 to HK$1.95 per Offer Share plus Downward Offer Price Adjustment[1] ) brokerage of 1.0%, SFC transaction levy of 0.0027% and Hong Kong Stock Exchange trading fee of 0.005% (payable in full on application in Hong Kong dollars, subject to refund on final pricing) (If the Offer Price is set at 10% below the bottom end of the indicative Offer Price range after making a Downward Offer Price Adjustment, the Offer Price will be HK$1.35 per Offer Share) Nominal value: US$0.0001 per Share Stock code: 2181

Sole Sponsor, Sole Global Coordinator and Sole Bookrunner

Application has been made by the Company to the Listing Committee of the Stock Exchange for the granting of the approval for the listing of, and permission to deal in, the Shares in issue and to be issued pursuant to the Global Offering (including the additional shares which may be issued upon the exercise of the Over-allotment Option and the Shares which may be issued pursuant to the exercise of the share options which were granted under the Pre-IPO Share Option Scheme). Assuming that the Hong Kong Public Offering becomes unconditional at or before 8:00 a.m. on Friday, May 31, 2019, it is expected that dealing in the Shares on the Stock Exchange will commence at 9:00 a.m. on Friday, May 31, 2019. In the event that the Over-allotment Option is exercised, an announcement will be made by the Company on the website of the Stock Exchange at www.hkexnews.hk and the website of the Company at www.mabpharm.cn .

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The Global Offering comprises the Hong Kong Public Offering of initially 78,358,000 Shares (subject to adjustment) and the International Offering of initially 705,222,000 Shares (subject to adjustment and Over-allotment Option) representing 10% and 90% of the total number of Offer Shares initially being offered under the Global Offering, respectively. The allocation of the Offer Shares between the Hong Kong Public Offering and the International Offering will be subject to reallocation as described in the section headed “Structure of the Global Offering” in the Prospectus. In accordance with Guidance Letter HKEX-GL91-18 issued by the Stock Exchange, if such reallocation is done in the circumstance that the International Offering are undersubscribed or other than pursuant to the clawback mechanism as described in the section headed “Structure of the Global Offering”, the total number of Offer Shares available under the Hong Kong Public Offering following such reallocation shall be not more than 156,716,000 Offer Shares, representing 20% of the number of the Offer Shares initially available under the Global Offering (before any exercise of the Over-allotment Option), and the Offer Price would be set at HK$1.50 (low-end of the indicative Office Price). In connection with the Global Offering, the Company is expected to grant the Over-allotment Option to the International Underwriter, which is exercisable by the Sole Global Coordinator (on behalf of the International Underwriter) from the Listing Date until 30 days after the last day for the lodging of applications under the Hong Kong Public Offering, to require the Company to issue up to an aggregate of 117,536,000 additional Shares, representing not more than 15% of the total number of Offer Shares initially available under the Global Offering.

Subject to the granting of the approval for listing of, and permission to deal in, the Shares on the Stock Exchange and compliance with the stock admission requirements of HKSCC, the Shares will be accepted as eligible securities by HKSCC for deposit, clearance and settlement in CCASS with effect from the date of commencement of dealings in the Shares on the Stock Exchange or any other date as determined by HKSCC. Settlement of transactions between participants of the Stock Exchange is required to take place in CCASS on the second Business Day after any trading day. All activities under CCASS are subject to the General Rules of CCASS and CCASS Operational Procedures in effect from time to time. All necessary arrangements have been made to enable the Shares to be admitted into CCASS.

The Offer Price will not be more than HK$1.95 per Offer Share and is expected to be not less than HK$1.50 per Offer Share, unless otherwise announced (subject to a reduction of up to 10% below the bottom end of the indicative Offer Price range) through making a Downward Offer Price Adjustment as set out in the Propectus. If the Offer Price is set after making a 10% Downward Offer Price Adjustment, the Offer Price will be HK$1.35 per Offer Share. Applicants under the Hong Kong

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Public Offering are required to pay, on application, the Maximum Offer Price of HK$1.95 per Offer Share plus brokerage fee of 1%, SFC transaction levy of 0.0027% and Stock Exchange trading fee of 0.005%, subject to refund if the Offer Price as finally determined is less than HK$1.95.

If the Company decides to reduce the Offer Price by making a Downward Offer Price Adjustment (a reduction of up to 10% below the bottom end of the indicative Offer Price range), the Company will separately announce the final Offer Price no later than Thursday, May 30, 2019 on the website of the Stock Exchange at www.hkexnews.hk and the Company’s website at www.mabpharm.cn .

Applications for the Hong Kong Offer Shares will only be considered on the basis of the terms and conditions set out in the Prospectus, the relevant Application Forms and the designated website (www.eipo.com.hk) for the White Form eIPO.

Applicants who would like the allotted Hong Kong Offer Shares to be issued in their own names should either (i) complete and sign the WHITE Application Forms or (ii) submit applications online through the designated website of the White Form eIPO Service Provider at www.eipo.com.hk through the White Form eIPO service. Applicants who would like the Hong Kong Offer Shares to be allotted in the name of HKSCC Nominees and deposited directly into CCASS for credit to their CCASS Investor Participant stock accounts or the stock accounts of their designated CCASS Participants maintained in CCASS should either (i) complete and sign the YELLOW Application Forms or (ii) give electronic application instructions to HKSCC via CCASS.

Copies of the WHITE Application Form, may be obtained during normal business hours from 9:00 a.m. on Monday, May 20, 2019 until 12:00 noon on Friday, May 24, 2019 from:

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1. the following branches of the receiving banks for the Hong Kong Public Offering:

Bank of China (Hong Kong) Limited

	Branch Name	Address
Hong Kong Island	Des Voeux Road West Road	111-119 Des Voeux Road
	Branch	West, Hong Kong
	Central District	B/F-2/F, Wing On House,
	(Wing On House) Branch	71 Des Voeux Road
		Central, Hong Kong
Kowloon	Whampoa Garden Branch	Shop G8B, Site 1,
		Whampoa Garden,
		Hung Hom, Kowloon
	Jordan Road Branch	1/F, Sino Cheer Plaza,
		23-29 Jordan Road,
		Kowloon
New Territories	Tai Po Branch	68-70 Po Heung Street,
		Tai Po Market,
		New Territories
	Yuen Long	8-18 Castle Peak Road,
	(Hang Fat Mansion) Branch	Yuen Long,
		New Territories
CMB Wing Lung Bank Limited
	Branch name	Address
Hong Kong Island	Head Office	45 Des Voeux Road
		Central
	Kennedy Town Branch	28 Catchick Street
	Aberdeen Branch	201 Aberdeen Main Road
Kowloon	Mongkok Branch	B/F Wing Lung Bank
		Centre, 636 Nathan Road
	San Po Kong Branch	8 Shung Lung Street

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1. the following address of the Hong Kong Underwriter:

China International Capital Corporation Hong Kong Securities Limited

29/F One International Finance Center,

• 1 Harbor View Street, Central, Hong Kong

Copies of the Prospectus, together with the YELLOW Application Form, may be obtained during normal business hours from 9:00 a.m. on Monday, May 20, 2019 until 12:00 noon on Friday, May 24, 2019 from the Depository Counter of HKSCC at 1/F, One & Two Exchange Square, 8 Connaught Place, Central, Hong Kong or from your stockbroker.

The WHITE or YELLOW Application Form completed in accordance with the instructions printed thereon, together with a cheque or banker’s cashier order attached and marked payable to “ BANK OF CHINA (HONG KONG) NOMINEES ” LIMITED — MABPHARM PUBLIC OFFER should be deposited in the special collection boxes provided at the designated branches of the receiving bank referred to above on such dates and during such time as specified in the Application Forms.

Applicants applying through the White Form eIPO service may submit applications through the designated website at www.eipo.com.hk (24 hours daily, except on the last application day) from 9:00 a.m. on Monday, May 20, 2019 until 11:30 a.m. on Friday, May 24, 2019 and the latest time for completing full payment of application monies in respect of such applications will be 12:00 noon on Friday, May 24, 2019 or such later time as described in the section headed “How to Apply for Hong Kong Offer Shares — 10. Effect of Bad Weather on the Opening of the Application Lists” in the Prospectus.

CCASS Participants can input electronic application instructions from 9:00 a.m. on Monday, May 20, 2019 until 12:00 noon on Friday, May 24, 2019 or such later time as described in the section headed “How to Apply for Hong Kong Offer Shares — 10. Effect of Bad Weather on the Opening of the application lists” in the Prospectus.

Please refer to the sections headed “Structure of the Global Offering” and “How to Apply for Hong Kong Offer Shares” in the Prospectus for details of the conditions and procedures of the Hong Kong Public Offering.

Irrespective of whether a Downward Offer Price Adjustment is made, the Company expects to announce the Offer Price, the level of indication of interest in the International Placing, the level of applications in the Hong Kong Public Offering and

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the basis of allocation of Hong Kong Offer Shares on or before Thursday, May 30, 2019 in the South China Morning Post (in English) and the Hong Kong Economic Times (in Chinese) and on the website of the Company at www.mabpharm.cn and the website of the Stock Exchange at www.hkexnews.hk .

The results of allocations (with the successful applicants’ identification document numbers, where applicable) under the Hong Kong Public Offering will be made available from Thursday, May 30, 2019 through a variety of channels at the times and dates and in the manner specified in the section headed “How to Apply for Hong Kong Offer Shares — 11. Publication of Results” in the Prospectus.

The Company will not issue temporary documents of title. Share certificates will only become valid certificates of title at 8:00 a.m. on Friday, May 31, 2019 provided that the Global Offering has become unconditional in all respects and the right of termination described in the section headed “Underwriting — Underwriting Arrangements and Expenses — Hong Kong Public Offering — Hong Kong Underwriting Agreement — Grounds for Termination” in the Prospectus has not been exercised. No receipt will be issued for sums paid on application. Dealings in the Shares on the Stock Exchange are expected to commence at 9:00 a.m. on Friday, May 31, 2019. The Shares will be traded in board lots of 2,000 Shares each. The stock code of the Shares will be 2181.

By order of the Board Mabpharm Limited Jiao Shuge Chairman

Hong Kong, May 20, 2019

As at the date of this announcement, the executive Directors are Dr. Qian Weizhu, Dr. Wang Hao, Mr. Li Yunfeng and Dr. Li Jing; the non-executive Directors are Mr. Guo Jianjun and Mr. Jiao Shuge; and the independent non-executive Directors are Mr. Guo Liangzhong, Dr. Zhang Yanyun and Dr. Liu Linqing.

Please also refer to the published version of this announcement in the South China Morning Post (in English) and the Hong Kong Economic Times (in Chinese).

1 Please refer to the Prospectus for definition of “Downward Offer Price Adjustment”.

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