Notice to attend an Extraordinary General Meeting in ExpreS2ion Biotech Holding AB (publ)

Helsingborg, Sweden, 14 September 2026 - The shareholders of ExpreS2ion Biotech Holding AB (publ), reg. no. 559033-3729 (the "Company"), are hereby invited to attend an extraordinary general meeting on 1 October 2026 at 10:00 (CEST) at Mindpark, Rönnowsgatan 8C in Helsingborg. Admission and registration for the meeting will commence at 9:45 (CEST).

The board of directors has, in accordance with the Company's articles of association, resolved that shareholders shall be entitled to exercise their voting rights by postal voting prior to the general meeting. Shareholders may therefore choose to exercise their voting rights at the meeting in person, through a proxy or by postal voting.

Right to participate and notification

The right to participate in the meeting is held by a person who:

1. is recorded in the share register maintained by Euroclear Nordics AB on 23 September 2026; and
2. has notified the Company of his or her intention to participate in the meeting in accordance with the instructions under the section "Notification for participation in person or through a proxy" no later than on 25 September 2026, or has submitted a postal vote in accordance with the instructions under the section "Instructions for postal voting" no later than on 25 September 2026.

Nominee-registered shares

Shareholders whose shares are registered in the name of a nominee must, in order to participate in the extraordinary general meeting and exercise their voting rights, temporarily re-register the shares in their own name in the share register maintained by Euroclear Nordics AB (so-called voting rights registration). The preparation of the general meeting share register as of the record date of 23 September 2026 will take into account voting rights registrations made no later than on 25 September 2026. This means that the shareholder must request that the nominee carries out such voting rights registration well in advance of that date.

Notification for participation in person or through a proxy

Shareholders who wish to participate in the meeting in person or through a proxy shall notify the Company no later than on 25 September 2026 to ExpreS2ion Biotech Holding AB (publ), "EGM 2026”, c/o Mindpark, Rönnowsgatan 8C, 252 25 Helsingborg, attn: Keith Alexander, or by e-mail to investor@expres2ionbio.com. The notification shall include the shareholder's name, address, telephone number (daytime), personal or registration number, shareholding and the number of any proxies/assistants.

A shareholder who does not wish to attend in person and does not wish to exercise his or her voting rights by postal voting may exercise his or her rights at the meeting through a proxy with a written, signed and dated power of attorney. The power of attorney may not be older than one year, unless a longer period of validity (however, no more than five years) has been stated in the power of attorney. If the power of attorney is issued by a legal entity, a copy of the certificate of registration or equivalent authorisation document for the legal entity shall be enclosed. To facilitate admission to the meeting, powers of attorney, certificates of registration and other authorisation documents should be sent either by e-mail to investor@expres2ionbio.com with the reference "EGM 2026" or by post to ExpreS2ion Biotech Holding AB (publ), ”EGM 2026”, c/o Mindpark, Rönnowsgatan 8C, 252 25 Helsingborg, Sweden, attn: Keith Alexander, no later than on 25 September 2026. Please note that notification of participation in the meeting must be made even if the shareholder wishes to exercise his or her voting rights at the meeting through a proxy. A submitted power of attorney does not constitute notification of participation in the meeting. Proxy forms in Swedish and English are available on the Company's website, investor.expres2ionbio.com.

Instructions for postal voting

Shareholders who wish to exercise their voting rights by postal voting shall use the postal voting form and follow the instructions available on the Company's website, investor.expres2ionbio.com. The postal vote must be received by the Company no later than on 25 September 2026. The postal voting form shall be sent to ExpreS2ion Biotech Holding AB (publ), “EGM 2026”, c/o Mindpark, Rönnowsgatan 8C, 252 25 Helsingborg, attn: Keith Alexander, or by e-mail to investor@expres2ionbio.com with the reference "EGM 2026".

If a shareholder submits a postal vote through a proxy, a written and dated power of attorney shall be enclosed with the postal voting form. Proxy forms are available upon request and are also available on the Company's website, investor.expres2ionbio.com. If the shareholder is a legal entity, a certificate of registration or equivalent authorisation document for the legal entity shall be enclosed. Shareholders may not attach special instructions or conditions to the postal vote. If this is done, the entire postal vote is invalid. Further instructions and conditions are set out in the postal voting form.

For questions regarding the meeting or to receive a postal voting form or a proxy form by post, please contact ExpreS2ion Biotech Holding AB (publ), ”EGM 2026”, c/o Mindpark, Rönnowsgatan 8C, 252 25 Helsingborg, attn: Keith Alexander, or by e-mail to investor@expres2ionbio.com.

Proposed agenda

1. Opening of the meeting and election of chairman of the meeting
2. Preparation and approval of the voting list
3. Election of one or two persons to verify the minutes
4. Determination of whether the meeting has been duly convened
5. Approval of the agenda
6. Resolution on authorisation for the board of directors to issue shares, convertible debentures and/or warrants
7. Closing of the meeting

Item 6 – Resolution on authorisation for the board of directors to issue shares, convertible debentures and/or warrants

The board of directors proposes that the extraordinary general meeting resolves to authorise the board of directors to, on one or more occasions prior to the next annual general meeting, resolve on the issuance of new shares, convertibles and/or warrants, with or without deviation from the shareholders' preferential rights, to be paid in cash, by way of contribution in kind and/or by way of set-off. The total number of shares that may be issued, or, if convertible debentures or warrants are issued, added by way of conversion or exercise of rights under the authorisation, shall not be limited in any way other than by the limits set out in the Company's articles of association as applicable from time to time.

The purpose of enabling the board of directors to resolve on issuances without preferential rights for the shareholders as set out above is primarily to raise new capital in order to broaden the Company's shareholder base, increase the Company's flexibility, make payment for guarantee undertakings in the form of shares, to fulfil the Company’s obligations under the put option agreement with Alumni Capital or in connection with acquisitions. To the extent that issuances are made with deviation from the shareholders' preferential rights, the issuance shall be made on customary market terms. If the board of directors deems it appropriate in order to facilitate the delivery of shares in connection with an issuance as set out above, this may be done at a subscription price corresponding to the quota value of the shares.

Authorisation

The board of directors, the chief executive officer, or any person designated by the board of directors or the chief executive officer, is authorised to make such minor adjustments to the resolution as may be required in connection with the registration of the resolution with the Swedish Companies Registration Office or due to other formal requirements.

Majority requirements

A valid resolution under this item 6 requires the support of shareholders representing at least two-thirds of both the votes cast and the shares represented at the general meeting.

Documents

Proxy forms, postal voting forms and other documents pursuant to the Swedish Companies Act will be available at the Company's office at Mindpark, Rönnowsgatan 8C in Helsingborg and on the Company's website, investor.expres2ionbio.com, no later than two weeks prior to the meeting. The documents will also be sent to shareholders who so request and provide their postal address.

Shareholders' right to request information

Shareholders are reminded of their right to request information from the board of directors and the chief executive officer at the meeting in accordance with Chapter 7, Section 32 of the Swedish Companies Act.

Processing of personal data

For information on how your personal data is processed, please refer to the privacy policy available on Euroclear's website: www.euroclear.com/dam/ESw/Legal/Integritetspolicy-bolagsstammor-svenska.pdf.

N.B. This notice has been prepared in both Swedish and English language versions. In the event of any discrepancies between the versions, the Swedish version shall prevail. 

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Helsingborg in September 2026
ExpreS2ion Biotech Holding AB (publ)
The Board of Directors

For further information about ExpreS2ion, please contact:
Bent U. Frandsen, CEO
Keith Alexander, CFO
E-mail: investor@expres2ionbio.com

Certified Adviser
Redeye Nordic Growth AB

About ExpreS2ion
ExpreS2ion is a clinical-stage biotechnology company developing active immunotherapies and vaccines for cancer and infectious diseases. Its lead asset, ES2B-C001, is a first-in-class active immunotherapy for HER2-expressing cancers, currently in Phase I clinical development. ES2B-C001 is built on ExpreS2ion's proprietary, Phase III-validated ExpreS2™ protein expression platform, which also underpins a portfolio of partnered development programmes and a contract services (CRO) business. ExpreS2ion develops novel VLP-based vaccines in association with AdaptVac ApS, of which ExpreS2ion owns 34%. ExpreS2ion Biotech Holding AB is listed on Nasdaq First North Growth Market. For additional information, please visit www.expres2ionbio.com.