Hørsholm, Denmark, 28 May 2026 – ExpreS2ion Biotech Holding AB (“ExpreS2ion” or “the Company”) today announces its first quarter 2026 results. The report is available as an attachment and on ExpreS2ion's website (www.expres2ionbio.com). Below is a summary of the report.

CEO Bent U. Frandsen comments:
“Q1 2026 demonstrated progress across our clinical and platform priorities. ES2B-C001 continued to generate preliminary immunogenicity data supporting continued clinical development, while the ExpreS2 platform received additional validation through our ongoing partnered malaria programmes, and the Nipah programme advanced into the GMP manufacturing stage. After the quarter, we reported drug-specific antibody responses across all nine evaluable patients and completed a rights issue that supports our path toward Phase I readouts by the end of 2026. We are focused on generating high-quality evidence to support ES2B-C001's next stage of development and future partnership opportunities.”

Summary of 2026 first quarter results, January – March 2026
Key income statement figures, SEK '000s

• Operating income: 6,868 (2,957)
• Profit/loss after financial items: -12,056 (-12,968)
• Profit/loss for the period: -9,590 (-11,440)

Key balance sheet figures, SEK '000s

• End of period cash balance: 21,843 (58,005)
• End of period total assets: 50,404 (80,603)
• End of period equity / asset ratio*: 52% (63%)

Number of shares

• Number of shares at end of the period: 3,530,233 (2,658,346)
• Average number of shares: 3,530,233 (2,658,346)
• Average number of shares (after dilution)**: 43,717,733 (3,563,888)

Earnings per share (EPS), SEK***

• Earnings per share for the period based on average number of shares: -2.72 (-4.30)
• Diluted earnings per share for the period: -0.22 (-3.21)

Figures in parenthesis are from the same period in 2025.
*Equity ratio: Shareholder’s equity divided by total capital.
** Potential dilutive effects in the calculation of the diluted earnings (loss) per share include those related to share issues. For the current quarter, these include share-based compensation programs (100,000), shares issued in the Rights Issue completed after the quarter-end (19,868,750), shares issued as remuneration for a guarantor of that rights issue (350,000), and potential shares to be issued as a result of warrant program TO 13 (19,868,750). For the prior year, this included shares related to warrants (805,542) and share-based compensation programs (100,000).
***Earnings per share defined as profit/loss for the period divided with the average number of shares for the period. Prior year earnings per share comparatives adjusted, reflecting changed date of share registration in average number of share calculations.

Webcast presentation of first quarter 2026 results
On May 28th, 2026 at 10:00 CET, ExpreS2ion CEO Bent Frandsen and CFO Keith Alexander will present a company update and the first quarter 2026 results and answer investors’ questions. More information and registration can be found via this link: https://www.inderes.dk/videos/expres2ion-biotech-presentation-of-q1-2026-interim-report

Key developments during the quarter included:

• On January 28th, ExpreS2ion announced that it had selected Northway Biotech as its cGMP contract development and manufacturing organization (CDMO) for its Nipah virus vaccine candidate.
• On February 3rd, ExpreS2ion reported updated immunogenicity observations from its ongoing Phase I clinical trial of ES2B-C001. Based on the data available at that time, five out of six evaluable patients demonstrated a drug-specific immune response, defined as an increase from baseline in anti-HER2 lambda light-chain antibody titers following treatment with ES2B-C001. The data remained early and under evaluation, and no formal conclusions could be drawn at that stage.
• On February 3rd, the Company announced that Redeye initiated equity research coverage of ExpreS2ion. In its initiation report, Redeye established a base case valuation of SEK 28 per share, with a bull case of SEK 44 and a bear case of SEK 7, based on its assessment of the Company’s clinical pipeline, technology platform, partner-led programs, and upcoming development milestones.
• On February 27th, the Board of Directors of ExpreS2ion Biotech Holding AB announced its intention to resolve on a new issue of units with preferential rights for existing shareholders of approximately SEK 53 million before transaction costs. In total, the Rights Issue was covered by subscription commitments and guarantee commitments of up to approximately SEK 32 million, corresponding to approximately 60 percent of the Rights Issue.
• On March 25th, the Company reported updated immunogenicity data from its ongoing Phase I clinical trial of ES2B-C001. The updated dataset showed anti-HER2-specific antibody responses in eight of nine evaluable patients, with antibody titres increasing over time following repeated dosing. Following review of the available safety and tolerability data, the independent Data Safety Monitoring Board (DSMB) supported further progression of the study, including expansion of the ongoing cohort and escalation to the next dose level. The trial remains active, with additional patient follow-up and sample analyses pending.

After the reporting period, subsequent events of note were:

• On April 1st, ExpreS2ion Biotech Holding AB announced that the Extraordinary General Meeting resolved to appoint Michel J. Baijot as a new member of the Board of Directors.
• On April 10th, the Company announced the publication of its patent application titled “Recombinant Production of Protein Having Xylosylated N-Glycans” by the Hong Kong Intellectual Property Department (HKIPD).
• On April 22nd, ExpreS2ion highlighted new Phase Ia clinical data from the University of Oxford’s BIO-002 study, providing further independent validation of the Company’s ExpreS2 platform in human clinical use.
• On May 4th, ExpreS2ion Biotech Holding AB announced the final outcome of the rights issue of units. The subscription price in the Rights Issue was SEK 1.60 per unit, corresponding to a subscription price of SEK 1.60 per share. The warrants of series TO 13 were issued free of charge. In total, 13,094,637 units were subscribed for with the support of unit rights, representing approximately 39.5 percent of the Rights Issue, and 1,168,535 units were subscribed for without the support of unit rights, representing approximately 3.5 percent of the Rights Issue. Thus, the Rights Issue was subscribed to a total of approximately 43.0 percent with and without unit rights. In addition, 5,605,578 units, corresponding to approximately 16.9 percent of the Rights Issue, were subscribed for by guarantors. The Rights Issue was thus subscribed to a total of approximately 59.9 percent. Through the Rights Issue, the Company initially received proceeds of approximately SEK 31.8 million before transaction costs. If all warrants of series TO 13 issued in the Rights Issue are exercised for the subscription of shares, at an exercise price corresponding to the subscription price in the Rights Issue, the Company will receive additional proceeds of approximately SEK 31.8 million before transaction costs.
• On May 19th, ExpreS2ion announced an update to the Phase I program for ES2B-C001. The updated design is intended to deliver a more informative translational data package, adds a maintenance treatment component, and is supported by a revised Phase II plan. ExpreS2ion also reported additional preliminary Phase I observations, including anti-HER2 antibody responses in 9 of 9 evaluable patients and no safety signals of concern identified to date, including in the first patient dosed in the 450 µg cohort. The Phase I primary readout target of end-2026 and Phase II initiation target of mid-2027 remained unchanged.

Certified Adviser
Redeye Nordic Growth AB

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

This press release constitutes inside information that ExpreS2ion Biotech Holding AB (publ) is obliged to make public pursuant to the EU Market Abuse Regulation 596/2014. The information was sent for publication, through the agency of the contact persons set out above, at the time stated by the Company’s news distributor, MFN, at the publication of this press release.

About ExpreS2ion
ExpreS2ion is a biotechnology company focused on the development of innovative active immunotherapies and vaccines for cancer and infectious diseases. The company has developed the ExpreS2™ platform, a proprietary protein expression technology used across more than 500 recombinant protein and virus-like particle (VLP) projects spanning research, diagnostics, and therapeutic development. Proteins produced using the ExpreS2 platform are being evaluated in multiple clinical programmes worldwide. The platform has also been applied in partnered development programmes that have progressed into late-stage clinical evaluation, including Phase III studies that have met their primary endpoints. The platform, marketed as GlycoX-S2™, includes functionally modified glycosylation variants designed to enhance immunogenicity and pharmacokinetics. ExpreS2ion develops novel VLP-based vaccines in association with AdaptVac ApS, of which ExpreS2ion owns 34%. ExpreS2ion Biotech AB is listed on Nasdaq First North Growth Market. For additional information, please visit www.expres2ionbio.com.

This information is information that ExpreS2ion Biotech Holding AB is obliged to make public pursuant to the EU Market Abuse Regulation. The information was submitted for publication, through the agency of the contact persons set out above, at 2026-05-28 08:30 CEST.

Attachments
260528 ExpreS2ion Q1 2026 Report