THIS ANNOUNCEMENT AND THE INFORMATION CONTAINED IN IT, IS RESTRICTED AND IS NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, IN WHOLE OR IN PART, DIRECTLY OR INDIRECTLY, IN, INTO OR FROM THE UNITED STATES, AUSTRALIA, CANADA, JAPAN, SOUTH AFRICA OR ANY OTHER JURISDICTION IN WHICH SUCH RELEASE, PUBLICATION OR DISTRIBUTION WOULD BE UNLAWFUL. PLEASE SEE THE IMPORTANT NOTICES IN THIS ANNOUNCEMENT.

6 November 2026

4basebio PLC

("4basebio" or the "Company")

Result of General Meeting and Total Voting Rights

CAMBRIDGE, UK - 6 November 2026 - 4basebio PLC (AIM: 4BB), a specialist in synthetic DNA manufacturing for next-generation genomic medicines and advanced therapies, announces that at the Company's General Meeting held earlier today, all resolutions were duly passed.

The General Meeting was convened by the Company to seek shareholder approval for the Capital Raise announced on 15 October 2026, in order to pass the required resolutions approving the grant of new authorities to the Directors to allot the New Shares pursuant to the Capital Raise, and to disapply statutory pre-emption rights in respect of such allotments.

Following the General Meeting, Admission of 485,436 VCT Placing Shares will occur on 9 November 2026, and Admission of 3,210,774 Non-VCT Placing Shares, Subscription Shares and Retail Offer Shares will occur on 10 November 2026.

The Capital Raise remains conditional upon: (1) the Admission of the New Shares occurring on 9 November 2026 and 10 November 2026 respectively; and (2) the Placing Agreement becoming unconditional in all respects and not having been terminated in accordance with its terms prior to the Admission of the Non-VCT Placing Shares, Subscription Shares and Retail Offer Shares on 10 November 2026.

Admission to trading on AIM and Total Voting Rights

Following completion of the Capital Raise and Admission of the Non-VCT Placing Shares, Subscription Shares and Retail Offer Shares on 10 November 2026, the Company's issued share capital will comprise 19,234,728 ordinary shares of 1 Euro each. Accordingly, the total number of voting rights in 4basebio at this time will be 19,234,728. This figure may be used by shareholders as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change to their interest in, the Company, under the Disclosure and Transparency Rules.

Unless otherwise defined, all capitalised terms used but not defined in this announcement shall have the meaning given to them in the announcement of the Capital Raise made by the Company at 7.00 a.m. on 15 October 2026.

Enquiries

4basebio PLC

+44 (0)12 2396 7943

Dr. Amy Walker - Chief Executive Officer

Richard Bungay - Chief Financial Officer

RBC Capital Markets (Global Co-ordinator, Joint Bookrunner and Joint Corporate Broker)

T: +44 (0)20 7653 4000

Kathryn Deegan - ECM

Max Avison - ECM Syndicate

Sandrine Cailleteau - Healthcare Advisory

Cavendish Capital Markets Limited (Joint Bookrunner and Joint Corporate Broker)

T: +44 (0)20 7220 0500

Geoff Nash, Andrea Callaghan - Corporate Finance

Nigel Birks - Healthcare Specialist Sales

Cairn Financial Advisers LLP (Nominated Adviser)

T: +44 (0)20 7213 0880

Jo Turner / Sandy Jamieson / Ed Downes

ICR Healthcare (Media and Investor Relations)

T: +44 (0)20 3707 5700

Jessica Hodgson / Ashley Tapp / Philip Marriage

About 4basebio

4basebio (AIM: 4BB) is a Cambridge-based biotechnology company pioneering the use of synthetic DNA to enable next-generation therapeutics and vaccines. Through its proprietary enzymatic DNA synthesis platform, 4basebio produces GMP-grade synthetic DNA and mRNA with superior speed, purity, and scalability, overcoming the limitations of plasmid-based systems. The company offers application-specific DNA constructs tailored to the diverse needs of gene therapies, genome editing, mRNA production, and DNA vaccines, helping partners accelerate proof-of-concept studies and reach clinical milestones more efficiently while maintaining the highest standards of safety and quality.

For more information, visit 4basebio.com.

IMPORTANT NOTICES

Neither this Announcement, nor any copy of it, may be taken or transmitted, published or distributed, directly or indirectly, in or into the United States, Canada, Australia, South Africa or Japan or to any persons in any of those jurisdictions or any other jurisdiction where to do so would constitute a violation of the relevant securities laws of such jurisdiction or to any persons in any of those jurisdictions. This Announcement is for information purposes only and does not constitute an offer to sell or issue, or the solicitation of an offer to buy, acquire or subscribe for any shares in the capital of the Company in the United States, Canada, Australia, South Africa or Japan or any other state or jurisdiction in which such offer or solicitation is not authorised or to any person to whom it is unlawful to make such offer or solicitation. Any failure to comply with these restrictions may constitute a violation of securities laws of such jurisdictions.

The Placing Shares referred to herein have not been, and will not be, registered under the United States Securities Act of 1933, (the "U.S. Securities Act"), or with any securities regulatory authority of any state or other jurisdiction of the United States and may not be offered or sold, pledged, taken up, exercised, resold, renounced, transferred or delivered, directly or indirectly in, into or within the United States absent registration under the U.S. Securities Act, except pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the U.S. Securities Act and in compliance with any applicable securities laws of any state or other jurisdiction of the United States. No public offering of the shares referred to in this Announcement is being made in the United States.

The Placing Shares are being offered and sold by the Company (i) to persons outside the United States in offshore transactions as defined in, and pursuant to, Regulation S under the Securities Act and (ii) to a limited number of "qualified institutional buyers" (as such term is used in Rule 144A under the Securities Act) in the United States in non-public transactions in reliance on Section 4(a)(2) of the Securities Act.

All offers of Placing Shares will be made pursuant to an exemption from the requirement to produce a prospectus under the Prospectus Regulation (Regulation (EU) 2017/1129) (the "Prospectus Regulation") in relevant member states of the European Economic Area ("EEA") and under the UK Public Offers and Admissions to Trading Regulations 2024 ("POATRs"). This Announcement is not being distributed by, nor has it been approved for the purposes of section 21 of the Financial Services and Markets Act 2000 ("FSMA") by, a person authorised under FSMA. This Announcement is being distributed to persons in the United Kingdom only in circumstances in which section 21(1) of FSMA does not apply. Members of the public are not eligible to take part in the Placing.

This announcement is being distributed only to, and is directed only at: (a) if in the United Kingdom, persons who are "qualified investors" within the meaning of Paragraph 15 of Schedule 1 of the POATRs who (i) are persons who have professional experience in matters relating to investments falling within Article 19(5) of the Financial Services and Markets Act (Financial Promotion) Order 2005, as amended (the "Order"); or (ii) are persons who are high net worth entities falling within Article 49(2)(a) to (d) of the Order (and only where the conditions contained in those Articles have been, or will at the relevant time be, satisfied); (b) if in the EEA, persons in member states who are "qualified investors" within the meaning of Article 2(e) of the Prospectus Regulation ("Qualified Investors"); and (c) persons to whom it may otherwise be lawfully communicated, (all such persons together being referred to as "Relevant Persons"). This announcement must not be acted on or relied on by persons who are not Relevant Persons in the United Kingdom and in any member state of the EEA. Any investment or investment activity to which this announcement relates is available only to Relevant Persons in the United Kingdom and in any member state of the EEA, and will be engaged in only with such persons.

Cavendish is authorised and regulated by the FCA in the United Kingdom and is acting as joint bookrunner, joint broker and retail offer coordinator exclusively for the Company and no one else in connection with this Announcement or any future transaction in connection with it. Cavendish will not regard any other person as a client and will not be responsible to anyone other than the Company for providing the protections afforded to their clients nor for the giving of advice in relation to any transaction, matter or arrangement of securities of the Company referred to in this Announcement. Neither Cavendish nor any of its affiliates, directors or employees owes or accepts any duty, liability or responsibility whatsoever (whether direct or indirect, consequential, whether in contract, tort, in delict, under statute or otherwise) to any person who is not a client of Cavendish in connection with the Placing or any matter referred to in this Announcement.

RBC is authorised by the Prudential Regulation Authority ("PRA") and regulated by the FCA and the PRA in the United Kingdom, and is acting as joint broker, global co-ordinator and joint bookrunner exclusively for the Company and no one else in connection with this Announcement or any future transaction in connection with it. RBC will not regard any other person as a client and will not be responsible to anyone other than the Company for providing the protections offered to their clients nor for the giving of advice in relation to any transaction, matter or arrangement of securities of the Company referred to in this Announcement. Neither RBC nor any of its affiliates, directors or employees owes or accepts any duty, liability or responsibility whatsoever (whether direct or indirect, consequential, whether in contract, tort, in delict, under statute or otherwise) to any person who is not a client of RBC in connection with the Placing or any matter referred to in this Announcement.