ExpreS2ion Biotech Announces Pareto Securities Analyst Note on First Patient Dosed in Phase I Trial

Hørsholm, Denmark, 24 June 2025 – ExpreS2ion Biotech Holding AB’s affiliate ExpreS2ion Biotechnologies ApS (“ExpreS2ion" or the “Company”) is pleased to announce that Pareto Securities has published a sponsored research update following the Company’s announcement on 23 June that the first patient has been dosed in its Phase I clinical trial evaluating the breast cancer immunotherapy candidate ES2B-C001. The update focuses on the significance of this milestone and the implications for the development of the program.

Key points from the Pareto Securities note:

• The first patient has been dosed with ES2B-C001, which was reported as well-tolerated.

• This marks a major milestone as ExpreS2ion’s first self-sponsored clinical trial.

• Dosing occurred even before regulatory approval of a protocol amendment submitted in May, indicating strong demand and highlighting the unmet medical need in HER2-positive metastatic breast cancer despite existing therapies, in Pareto’s view.

• The protocol amendment, if approved as expected in Q3, could broaden therapeutic options and further increase trial attractiveness.

• Pareto sees longer-term potential to expand development into earlier-stage disease and/or other HER2-expressing tumour types.

• The price target remains unchanged at SEK 303 per share.

The full Pareto Securities report, along with previously published analyst reports about ExpreS2ion, is available on the company’s investor website here: Analyst Reports.