THIS ANNOUNCEMENT IS NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, IN WHOLE OR IN PART, DIRECTLY OR INDIRECTLY IN OR INTO OR FROM ANY JURISDICTION WHERE TO DO SO WOULD CONSTITUTE A VIOLATION OF THE RELEVANT LAWS OR REGULATIONS OF THAT JURISDICTION.

THIS ANNOUNCEMENT IS MADE FOR INFORMATION PURPOSES ONLY AND DOES NOT CONSTITUTE AN OFFER TO SELL OR ISSUE OR SOLICITATION TO BUY, SUBSCRIBE FOR OR OTHERWISE ACQUIRE SHARES IN ALLERGY THERAPEUTICS PLC IN ANY JURISDICTION IN WHICH ANY SUCH OFFER OR SOLICITATION WOULD BE UNLAWFUL.

THE SECURITIES DISCUSSED HEREIN MAY NOT BE OFFERED OR SOLD IN THE UNITED STATES, UNLESS REGISTERED UNDER THE U.S. SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR PURSUANT TO AN EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, REGISTRATION UNDER THE SECURITIES ACT. NO PUBLIC OFFERING OF THE SECURITIES DISCUSSED HEREIN IS BEING MADE IN THE UNITED STATES AND THE INFORMATION CONTAINED HEREIN DOES NOT CONSTITUTE AN OFFERING OF SECURITIES FOR SALE IN THE UNITED STATES AND ALLERGY THERAPEUTICS PLC DOES NOT CURRENTLY INTEND TO REGISTER ANY SECURITIES UNDER THE SECURITIES ACT. ADDITIONALLY, THE SHARES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE UNITED STATES SECURITIES AND EXCHANGE COMMISSION OR ANY OTHER SECURITIES COMMISSION OR REGULATORY AUTHORITY IN THE UNITED STATES, NOR HAVE ANY OF THE FOREGOING AUTHORITIES PASSED UPON OR ENDORSED THE MERITS OF THE EQUITY FINANCING. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENCE IN THE UNITED STATES.

THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION FOR THE PURPOSES OF THE MARKET ABUSE REGULATION (EU) NO. 596/2014 AS IT FORMS PART OF UNITED KINGDOM DOMESTIC LAW BY VIRTUE OF THE EUROPEAN (WITHDRAWAL) ACT 2018, AS AMENDED ("MAR"). UPON THE PUBLICATION OF THIS ANNOUNCEMENT, THE INSIDE INFORMATION IS NOW CONSIDERED TO BE IN THE PUBLIC DOMAIN FOR THE PURPOSES OF MAR.

Allergy Therapeutics plc

("Allergy Therapeutics", the "Group" or "Company")

Publication of Open Offer Circular

Amendment to existing Facility Agreement

27 September 2023 Allergy Therapeutics plc (AIM: AGY), the integrated commercial biotechnology company specialising in allergy vaccines, announces that further to the Company's announcements on 6 April 2023 and 22 September 2023, the Company has today posted a circular to Qualifying Shareholders in relation to the Open Offer (the "Circular"). The Circular will be available shortly to Qualifying Shareholders on the Company's website: https://www.allergytherapeutics.com/investors/shareholder-services/. Details of the Open Offer timetable are set out below.

As previously announced on 6 April 2023, ZQ Capital, acting through its affiliate SkyGem Acquisition, has agreed to underwrite the Open Offer by subscribing at the Issue Price of 1 pence per Ordinary Share for any Open Offer Shares not taken up by Qualifying Shareholders under the Open Offer.

Unless otherwise defined, capitalised terms in this announcement shall have the meaning as set out in the Circular.

Amendment to existing Facility Agreement

On 26 September 2023, the Company entered into an amendment to the Facility Agreement dated 6 April 2023 with Southern Fox and SkyGem Acquisition (the "Lenders") (the "Extension Facility") pursuant to which, subject to completion of the Equity Financing, the repayment of all amounts due under the Facility in full and the grant of a supplemental English law security over substantially all of the assets of the Company and its subsidiaries incorporated in England and Wales (the "Additional Security"), the Lenders have agreed to make available to the Company an additional total principal sum of up to £15 million on an uncommitted basis (the "Additional Facility Amount"). Under the Extension Facility, the Additional Facility Amount may be drawn by the Company during the period to 31 January 2024 with a minimum drawdown amount of £3 million per utilisation, and interest of 18 per cent. per annum shall be payable on any such amounts drawn. A drawdown under the Extension Facility shall require the consent of the Lenders and as such the Additional Facility Amount does not represent committed funding. The Extension Facility must be repaid in full by 31 December 2025. To provide security for any amounts drawn under the Extension Facility, the existing security package under the Facility Agreement will remain in place following repayment of the Facility on or around completion of the Equity Financing and the Additional Security will be granted.

The Extension Facility is deemed to be a related party transaction pursuant to Rule 13 of the AIM Rules by virtue of Southern Fox and ZQ Capital (together with its affiliates, SkyGem Acquisition, ZQ Capital and Zheqing (Simon) Shen) being substantial shareholders of the Company (within the meaning of the AIM Rules for Companies).

The Directors of the Company who are independent of the Facility and the Extension Facility, being all of the Directors save for Zheqing (Simon) Shen and Anthony Parker consider, having consulted with its nominated adviser Panmure Gordon, that the terms of the Extension Facility are fair and reasonable insofar as the Company's shareholders are concerned.

Open Offer Timetable

The Rule 9 Mandatory Offer by SkyGem Acquisition, an indirect wholly-owned subsidiary of funds managed by ZQ Capital, as outlined in the Company's announcement entitled "£40.75 million Facility with associated Equity Financing" on 6 April 2023, is expected to be launched shortly after Admission. Further details of the Rule 9 Mandatory Offer are available in ZQ Capital's announcement entitled "Statement Regarding Possible Mandatory Cash Offer" on 6 April 2023.

Each of the times and dates in this announcement refer to British Summer Time (BST) and are subject to change. Any such change will be notified by an announcement through a Regulatory Information Service.

Directors' Participation in the Open Offer

Peter Jensen and Anthony Parker intend to participate in the Open Offer. These Directors intend to apply for their Open Offer Entitlements under the Open Offer, such Open Offer Entitlements amounting to, in the aggregate, a total of 3,450,000 Open Offer Shares:

The participation in the Open Offer by Peter Jensen and Anthony Parker is also deemed to be a related party transaction pursuant to Rule 13 of the AIM Rules. The Directors of the Company who are deemed to be independent of the Open Offer, being Manuel Llobet, Cheryl MacDiarmid and Mary Tavener, having consulted with the Company's nominated adviser Panmure Gordon, have concluded that the terms of the participation of certain Directors in the Open Offer are fair and reasonable insofar as Shareholders are concerned.

Admission and Settlement

Application will be made to the London Stock Exchange for the 4,074,612,532 New Shares, pursuant to the Equity Financing, to be admitted to trading on AIM. Admission is expected to take place, and dealings in the New Shares on AIM are expected to commence, at 8:00 a.m. on 16 October 2023 (or such later date as may be agreed between the Company and the Investors, being no later than the Long Stop Date). No temporary documents of title will be issued.

Upon Admission, the Enlarged Share Capital is expected to be 4,753,717,153 Ordinary Shares*. On this basis, the New Shares will represent approximately 85.71 per cent. of the Enlarged Share Capital.

*excluding any new Ordinary Shares issued following the date of this announcement pursuant to the exercise of share options.

For further information, please contact:

Allergy Therapeutics

Manuel Llobet, Chief Executive Officer

Shaun Furlong, Chief Financial Officer

+44 (0)1903 845 820

Panmure Gordon (Nominated Adviser and Broker)

Emma Earl, Mark Rogers, Freddy Crossley, Corporate Finance

Rupert Dearden, Corporate Broking

+44 (0)20 7886 2500

Consilium Strategic Communications

Mary-Jane Elliott / David Daley / Davide Salvi

+44 (0)20 3709 5700

[email protected]

Notes for editors:

About Allergy Therapeutics

Allergy Therapeutics is an international commercial biotechnology company, headquartered in the UK, focussed on the treatment and diagnosis of allergic disorders, including aluminium free immunotherapy vaccines that have the potential to cure disease. The Group sells proprietary and third-party products from its subsidiaries in nine major European countries and via distribution agreements in an additional ten countries. Its broad pipeline of products in clinical development includes vaccines for grass, tree, house dust mite and peanut. For more information, please see www.allergytherapeutics.com.