Proposed Fundraise to raise approximately £12.5m

LONDON and PHILADELPHIA - October 5, 2026 - Avacta Therapeutics (AIM: AVCT, the "Company", "Avacta"), a life sciences company developing innovative, targeted oncology drugs, today announces that the Company intends to raise minimum gross proceeds of approximately £12.5 million through a placing (the "Placing") of new ordinary shares of 10 pence each in the capital of the Company ("Ordinary Shares") (the "Placing Shares") together with a subscription for new Ordinary Shares (the "Subscription Shares") (the "Subscription"), in each case at an issue price of 68 pence per new Ordinary Share (the "Issue Price") (together, the "Fundraise").

Background to and reasons for the Fundraise

Preliminary Phase 1 data across the first three dose levels demonstrate key findings of a clean safety profile, including at a payload dose approximately 50% higher than the maximum tolerated dose (MTD) of conventional exatecan. Additionally, the clinical pharmacokinetic (PK) data demonstrated exceptional alignment with the preclinical modelling, with evidence of the controlled release of exatecan in patients for days following dosing.

These data greatly increase the confidence of the Board that the safety profile, tumor selectivity and anti-tumor efficacy observed in the preclinical studies of AVA6103 will translate into the clinic and significantly strengthen the Company's partnering position. The first efficacy data from FOCUS-01 is anticipated in H1 2027.

As previously announced, the Company currently has a cash runway into early Q1 2027 and is continuing discussions with potential partners in respect of its Next-Generation assets. The Fundraise is intended to extend this runway to further strengthen the Company's partnering position and balance sheet.

The net proceeds of the Fundraise will be used as follows:

• In addition, approximately £2.5 million will be used to satisfy the next quarterly Convertible Bond repayment due on 20 October 2026, in cash.

Capital Access Window

As announced at 07.01 a.m. on 30 September 2026, the Company has decided to utilise a Capital Access Window. This is a voluntary pause to the trading of a company's shares to make it easier for companies to reach a broader range of investors during a fundraise. Therefore, from 7:30 a.m. (BST) on 30 September 2026, the Company's shares entered a Capital Access Window trading halt and trading paused and will remain so until a further announcement is made detailing the results of the Fundraise.

The Issue Price represents a discount of approximately 5.6% to the closing mid-market price of 72 pence per Existing Ordinary Share on 29 September 2026, being the last trading day prior to the commencement of the Company's Capital Access Window.

Zeus Capital Limited ("Zeus Capital") is acting as sole broker and sole bookrunner (the "Bookrunner") in connection with the Placing. Beech Hill Securities, Inc. ("Beech Hill") is acting as private placement agent ("Placing Agent") to the Company. The Placing Shares are being offered in the UK by way of an accelerated bookbuild available to qualifying investors (the "Accelerated Bookbuild"), which will be launched immediately following the release of this Announcement, in accordance with the terms and conditions set out in Appendix 1 to this Announcement.

Additional details of the Placing and Subscription

Richard Hughes, Non-Executive Chaiman of the Company, Patrick Vink, Non-Executive Deputy Chairman of the Company, David Bryant, Non-Executive Director of the Company and Mats Blom, Non-Executive Director of the Company, (together, the "Subscribers"), have indicated their intention to subscribe for an aggregate amount of approximately £660,000 through the issue of 969,000 new Ordinary Shares at the Issue Price pursuant to the Subscription.

Neither the Placing nor the Subscription have been underwritten.

The timing of the closing of the Accelerated Bookbuild and the allocation of Placing Shares to be issued at the Issue Price are to be determined at the discretion of the Company and the Bookrunner.

A further announcement confirming the results of the Accelerated Bookbuild and further details of the Subscription will be released by the Company following the close of the Accelerated Bookbuild.

THE PLACING

The Company is seeking to conditionally place with certain current shareholders and new investors approximately 17,413,352 Placing Shares at the Issue Price to raise proceeds of approximately £11.8 million (before fees and expenses). The Placing is not being underwritten.

The Placing will be utilising the Company's existing share allotment authorities and powers.

The Issue Price of 68 pence per Placing Share represents a 5.6% discount to the closing mid-market price per Ordinary Share of 72 pence on 29 September 2026, being the last trading day prior to the commencement of the Company's Capital Access Window.

The Placing is conditional upon, inter alia, the Placing Agreement not having been terminated in accordance with its terms and admission of the new Ordinary Shares becoming effective.

The Placing Shares will, when issued and fully paid, rank pari passu in all respects with the Existing Ordinary Shares, including the right to receive all dividends and other distributions declared, made or paid after the date of Admission.

DETAILS OF THE PLACING AGREEMENT

On 5 October 2026, the Company, Zeus Capital and Beech Hill entered into the Placing Agreement, pursuant to which Zeus Capital (as Bookrunner) and Beech Hill (as Placing Agent) have each agreed, subject to certain conditions, to use their reasonable endeavours to procure subscribers for the Placing Shares pursuant to the Placing.

The Placing Agreement contains customary representations, warranties and undertakings and an indemnity from the Company in favour of Zeus Capital and Beech Hill, together with provisions which enable Zeus Capital to terminate the Placing Agreement in accordance with its terms in certain customary circumstances prior to Admission.

The obligations of Zeus Capital and Beech Hill under the Placing Agreement are conditional, inter alia, upon Admission occurring by 8.00 a.m. on 9 October 2026 (or such later date as Zeus Capital and the Company may agree).

The Placing Agreement provides for payment by the Company to each of Zeus Capital and Beech Hill of a commission of 5.0 per cent of the capital raised via the Placing, based on the number of Placing Shares placed by them respectively, multiplied by the Issue Price.

The Company will bear all other expenses of, and incidental to, the Placing, including the fees of the London Stock Exchange, printing costs, registrar's fees, and all legal and accounting fees of the Company.

In addition, on 5 October 2026 the Company and Strand Hanson Limited ("Strand Hanson") entered into an agreement containing customary representations, warranties and undertakings and an indemnity from the Company in favour of Strand Hanson in respect of the Fundraise and Admission.

THE SUBSCRIPTION

Richard Hughes, Non-Executive Chaiman of the Company, Patrick Vink, Non-Executive Deputy Chairman of the Company, David Bryant, Non-Executive Director of the Company and Mats Blom, Non-Executive Director of the Company, (together, the "Subscribers"), have indicated their intention to subscribe for an aggregate amount of £660,000 through the issue of 969,000 new Ordinary Shares at the Issue Price pursuant to the Subscription. The Subscription is not being underwritten.

The Subscription will be conditional, inter alia, on Admission occurring and the Placing Agreement not being terminated prior to Admission. Further details of the Subscription are expected to be announced following closure of the Accelerated Bookbuild.

RELATED PARTY TRANSACTION

Richard Hughes, Non-Executive Chaiman of the Company, is an associate of Zeus Capital being a director and majority shareholder of Zeus Capital. Accordingly, Zeus Capital is a related party of the Company and the payment of a 5.0 per cent. commission on the value of the Placing Shares placed by Zeus Capital, being approximately £573,000 (the "Zeus Commission") pursuant to the terms of the Placing Agreement, is deemed to be a related party transaction under Rule 13 of the AIM Rules for Companies.

The independent directors of the Company in respect of the payment of the Zeus Commission, being Patrick Vink, Mats Blom, David Bryant, Christina Coughlin, and Mark Goldberg, consider, having consulted with the Company's Nominated Adviser, Strand Hanson, that the Zeus Commission is fair and reasonable insofar as Shareholders are concerned.

ADMISSION

Application will be made to the London Stock Exchange for the admission of the Placing Shares and the Subscription Shares to trading on AIM ("Admission"). It is expected that Admission will take place, and that trading will become effective and dealings in the new Ordinary Shares will commence on AIM, at 8.00 a.m. on 9 October 2026. The Placing Shares and the Subscription Shares will be issued fully paid and will rank pari passu in all respects with the Company's Existing Ordinary Shares.

INFORMATION TO DISTRIBUTORS

UK product governance

EEA product governance

APPENDIX 1

("Representatives"); nor

• to the extent not contained within (a) or (b) or (c), any person connected with the Bookrunner as defined in the FSMA ((b) and (c) being together "affiliates" and individually an "affiliate" of the Bookrunner),

shall have any responsibility or liability (including to the extent permissible by law, any fiduciary duties) to Placees or to any other person whether acting on behalf of a Placee or otherwise. In particular, neither the Bookrunner, the Company, nor any of their respective Representatives shall have any responsibility or liability (including to the extent permissible by law, any fiduciary duties) in respect of the conduct of the Accelerated Bookbuild and/or the Placing or of such alternative method of effecting the Placing as the Bookrunner and the Company may determine. Each Placee acknowledges and agrees that the Company is responsible for the allotment of the Placing Shares to the Placees and the Bookrunner shall have no liability to the Placees for any failure by the Company to fulfil those obligations.

• The Placing Shares will be allotted and issued subject to the terms and conditions of this Appendix and each Placee's commitment to subscribe for Placing Shares on the terms set out herein will continue notwithstanding any amendment that may in future be made to the terms and conditions of the Placing and Placers will have no right to be consulted or require that their consent be obtained with respect to the Company's or the Bookrunner's conduct of the Placing.

Conditions of the Placing

The Placing is conditional upon the Placing Agreement becoming unconditional and not having been terminated in accordance with its terms. The Bookrunner's obligations under the Placing Agreement in respect of the Placing Shares are conditional on, inter alia:

• the Placing Terms having been executed by the Company and the Bookrunner;
• the publication by the Company of the Placing Results Announcement through a Regulatory Information Service as soon as reasonably practicable following the execution of the Placing Terms;
• the Company not being in breach of any of its obligations and undertakings under the Placing Agreement which fall to be performed or satisfied prior to Admission save to the extent such breach, in the opinion of the Banks (acting in good faith), is not material;
• each of the warranties given by the Company contained in the Placing Agreement being true, accurate and not misleading: (i) as at the date of the Placing Agreement; (ii) as at the time of the execution of the Placing Terms; and (iii) as at and on Admission, in each case, as though they had been given and made at such times and on such dates by reference to the facts and circumstances from time to time subsisting;
• no matter having arisen prior to Admission in respect of which indemnification or contribution might, in the opinion of the Banks (acting in good faith), reasonably be expected to be sought under the Placing Agreement;
• the Company having allotted, subject only to Admission, the Fundraise Shares in accordance with the Placing Agreement;
• the release of the Close of Capital Access Window Announcement (as defined in the Placing Agreement) and the resumption in trading of the Ordinary Shares on AIM by no later than Admission;
• Admission occurring no later than 8.00 am on 9 October 2026 (or such later time and/or date the Company and the Bookrunner may agree),

(each a "Closing Condition").

If, at Admission, any of the Closing Conditions is not fulfilled or, where permitted, waived or extended by the Banks in accordance with the Placing Agreement, the Placing will lapse and the Placees rights and obligations hereunder in relation to the Placing Shares shall cease and terminate at such time and each Placee agrees that no claim can be made by or on behalf of the Placee (or any person on whose behalf the Placee is acting) in respect thereof.

The Banks may, at its discretion and upon such terms and conditions as it thinks fit, waive satisfaction of certain of the Closing Conditions (save that Conditions (a), (b), (f) and 2(h) cannot be waived) or extend the time provided for their satisfaction. Any such waiver or extension will not affect Placees' commitments as set out in this Announcement.

Neither of the Banks nor any of their respective affiliates nor the Company shall have any liability to any Placee (or to any other person whether acting on behalf of a Placee or otherwise) in respect of any decision they may make as to whether or not to waive or to extend the time and/or date for the satisfaction of any condition to the Placing, nor for any decision they may make as to the satisfaction of any condition or in respect of the Placing generally and by participating in the Placing each Placee agrees that any such decision is within the absolute discretion of the Banks.

Right to terminate under the Placing Agreement

The Bookrunner, in its absolute discretion acting in good faith, may prior to Admission terminate the Placing Agreement in accordance with its terms in the event that certain circumstances arise at any time prior to Admission, including, among other things:

• any statement in any document or announcement issued or published by or on behalf of the Company in connection with the Fundraise is or has become untrue, inaccurate or misleading in any respect, or any matter has arisen which would, if such document or announcement had been issued at that time, constitute an inaccuracy or omission from such document or announcement;
• there has been a breach by the Company of any of its obligations under the Placing Agreement save for any breach which, in the opinion of the Bookrunner (acting in good faith), is not material;
• there has been a breach by the Company of any of the warranties or representations contained in the Placing Agreement or any of such warranties or representations is not, or ceases to be, true, accurate and not misleading;
• there has been a breach of any provision of any Subscription Letter or a waiver of any of the conditions thereto save for any breach which, in the opinion of the Bookrunner (acting in good faith), is not material;
• in the opinion of the Bookrunner (acting in good faith), there has been a Material Adverse Change whether or not foreseeable at the date of the Placing Agreement;
• upon the occurrence of certain force majeure events (including any escalation of the war in the Middle East); or
• if the Company's application for Admission is withdrawn or refused by the London Stock Exchange or, in the opinion of the Bookrunner (acting in good faith), will not be granted.

By participating in the Placing, each Placee agrees with the Company and the Bookrunner that the exercise or non-exercise by the Bookrunner of any right of termination or other right or other discretion under the Placing Agreement shall be within the absolute discretion of the Bookrunner or for agreement between the Company and the Bookrunner and that neither the Company nor the Bookrunner need make any reference to, or consult with, Placees and that none of the Company, the Bookrunner nor any of their respective affiliates or its or their respective Representatives shall have any liability to Placees whatsoever in connection with any such exercise or failure to so exercise or otherwise.

No prospectus

The Placing Shares are being offered to a limited number of specifically invited persons only and will not be offered in such a way as to require any prospectus or other offering document to be published. No offering document or prospectus has been or will be submitted to be approved by the FCA or submitted to the London Stock Exchange in relation to the Placing or the Placing Shares.

Each Placee, by participating in the Placing, agrees that the content of this Announcement is exclusively the responsibility of the Company and confirms that it has neither received nor relied on any other information (other than Publicly Available Information), representation, warranty or statement made by or on behalf of the Company, the Nominated Adviser or the Banks or any other person and none of the Company, the Nominated Adviser, the Banks nor any other person acting on such person's behalf nor any of their respective Representatives has or shall have any liability for any Placee's decision to participate in the Placing based on any other information, representation, warranty or statement which the Placees may have obtained or received. Each Placee acknowledges and agrees that it has relied on its own investigation of the business, financial or other position of the Company in accepting a participation in the Placing. No Placee should consider any information in this Announcement to be legal, tax or business advice. Nothing in this paragraph shall exclude the liability of any person for fraud or fraudulent misrepresentation by that person.

Application for admission to trading

Application will be made to the London Stock Exchange for admission of the Placing Shares to trading on AIM. It is expected that Admission will take place at 8.00 a.m. on 9 October 2026 (or such later time or date as the Company and the Bookrunner may agree, not being later than the Final Date) and that dealings in the Placing Shares on AIM will commence at the same time.

Registration and settlement

Settlement of transactions in the Placing Shares following Admission will take place within the CREST system, subject to certain exceptions. Settlement within CREST is expected to occur on 9 October 2026 ("Settlement Date"). Settlement will take place on a delivery versus payment basis. However, the Bookrunner and the Company reserve the right to require settlement for, and delivery of, the Placing Shares (or any part thereof) to Placees by such other means that they deem necessary if delivery or settlement is not possible or practicable within CREST within the timetable set out in this Announcement or would not be consistent with the regulatory requirements in the Placee's jurisdiction.

Each Placee allocated Placing Shares in the Placing will be sent a form of confirmation in accordance with the standing arrangements in place with the Bookrunner stating the number of Placing Shares allocated to it at the Issue Price, the aggregate amount owed by such Placee to the Bookrunner and settlement instructions. Each Placee agrees that it will do all things necessary to ensure that delivery and payment is completed in accordance with the standing CREST or certificated settlement instructions in respect of the Placing Shares that it has in place with the Bookrunner.

The relevant settlement details for the Placing Shares are as follows:

Insofar as Placing Shares are registered in a Placee's name or that of its nominee or in the name of any person for whom a Placee is contracting as agent or that of a nominee for such person, such Placing Shares should, subject as provided below, be so registered free from any liability to United Kingdom stamp duty or stamp duty reserve tax. If there are any circumstances in which any United Kingdom stamp duty or stamp duty reserve tax or other similar taxes or duties (including any interest and penalties relating thereto) is payable in respect of the allocation, allotment, issue, sale, transfer or delivery of the Placing Shares (or, for the avoidance of doubt, if any stamp duty or stamp duty reserve tax is payable in connection with any subsequent transfer of or agreement to transfer Placing Shares), none of the Nominated Adviser, the Banks nor the Company shall be responsible for payment thereof.

Placees will not be entitled to any fee or commission in connection with the Placing.

Representations, warranties, undertakings and further terms

• except to the extent it is compliant with and has executed and delivered, an investor letter as required by the Placing Agent, and any prospective beneficial owner for whose account or benefit it is purchasing the Placing Shares, is and, at the time the Placing Shares are subscribed for, will be located outside the United States and is acquiring the Placing Shares in an "offshore transaction" as defined in, and in accordance with, Regulation S under the Securities Act;
• it understands that the Placing Shares:
• it is not, and any person on whose behalf it is acting is not, and at the time the Placing Shares are subscribed for, neither it nor the beneficial owner of the Placing Shares will be, a resident of, nor have an address in, Australia, Japan, the Republic of South Africa or any province or territory of Canada or any other jurisdiction in which it is unlawful to make or accept an offer to acquire the Placing Shares;
• it will not offer, sell, transfer, pledge or otherwise dispose of any Placing Shares except:
• in an offshore transaction in accordance with Rule 903 or Rule 904 of Regulation S under the Securities Act; or
• pursuant to another exemption from registration under the Securities Act, if available,
• it understands that there may be certain consequences under United States and other tax laws resulting from an investment in the Placing Shares and it has made such investigation and has consulted its own independent advisers or otherwise has satisfied itself concerning, without limitation, the effects of United States federal, state and local income tax laws and foreign tax laws generally;
• it:
• is able to sustain a complete loss of an investment in the Placing Shares; and
• has no need for liquidity with respect to its investment in the Placing Shares;
• it is not:
• an entity or an individual with whom transactions are prohibited under the US Foreign Corrupt Practices Act of 1977 or is the subject of any economic sanction programmes administered by, or regulations promulgated by, the Office of Foreign Assets Control of the US Department of the Treasury;
• named on the UK Sanctions List; or
• it irrevocably appoints any duly authorized officer of the Bookrunner as its agent for the purpose of executing and delivering to the Company and/or the Registrars any documents on its behalf necessary to enable it to be registered as the holder of any of the Placing Shares for which it agrees to acquire upon the terms of this Announcement;
• it is acting as principal only in respect of the Placing or, if it is acting for any other person: (i) it is duly authorized to do so and has full power to make the acknowledgements, warranties, representations, confirmations, undertakings, and agreements and give the indemnities herein on behalf of each such person; and (ii) it is and will remain liable to the Company and/or the Bookrunner for the performance of all its obligations as a Placee in respect of the Placing (regardless of the fact that it is acting for another person). Each Placee agrees that the provisions of this paragraph shall survive the resale of the Placing Shares by or on behalf of any person for whom it is acting;
• if in the United Kingdom, it is a UK Qualified Investor and a person (i) having professional experience in matters relating to investments who falls within the definition of "investment professionals" in Article 19(5) of the Order or (ii) who falls within Article 49(2) (a) to (d) ("High Net Worth Companies, Unincorporated Associations, etc") of the Order, or (iii) to whom it may otherwise lawfully be communicated and if in the EEA, it is a EEA Qualified Investor;
• it has only communicated or caused to be communicated and will only communicate or cause to be communicated any invitation or inducement to engage in investment activity (within the meaning of section 21 of the FSMA) relating to the Placing Shares in circumstances in which section 21(1) of the FSMA does not require approval of the communication by an authorized person and it acknowledges and agrees that this Announcement has not been approved by the Bookrunner in its capacity as an authorized person under section 21 of the FSMA and it may not therefore be subject to the controls which would apply if it was made or approved as financial promotion by an authorized person;
• unless otherwise specifically agreed with the Nominated Adviser and the Bookrunner in writing, in the case of a Relevant Person in the United Kingdom who acquires any Placing Shares pursuant to the Placing, it is a 'Qualified Investor' within the meaning of paragraph 15 of Schedule 1 of POATR and in the case of a Relevant Person in a member state of the EEA who acquires any Placing Shares pursuant to the Placing, that it is a 'Qualified Investor' within the meaning of Article 2(e) of the EU Prospectus Regulation;
• a communication that the Placing or the book is "covered" (i.e. indicated demand from investors in the book equals or exceeds the amount of the securities being offered) is not any indication or assurance that the book will remain covered or that the Placing and securities will be fully distributed by Zeus Capital. Zeus Capital reserves the right to take up a portion of the securities in the Placing as a principal position at any stage at its sole discretion, among other things, to take account of the Company's objectives, MiFID II requirements and/or its allocation policies;
• it has the funds available to pay for the Placing Shares for which it has agreed to subscribe;
• time is of essence as regards its obligations under this Appendix;
• process its personal data for the Company's or Registrars' internal administration; and

Miscellaneous

APPENDIX 2

DEFINITIONS