ExpreS2ion Biotech (EXPRS2) Aktiespararna Aktiedagen summary

Disease and Market Overview

• Breast cancer is the most common cancer in women, with 2.3 million new cases and 685,000 deaths annually; HER2-expressing tumors are particularly challenging due to high relapse rates and resistance to current therapies.

• The global breast cancer market is valued at €27 billion, growing at 7% CAGR, with HER2-targeting drugs accounting for over €10 billion annually.

• HER2-positive, HER2-low, and HER2-ultra low segments represent significant unmet needs and market opportunities.

• Expansion into HER2-positive gastric cancer could increase the addressable market to over €5 billion per year.

• Incidence and mortality are projected to rise significantly by 2040, highlighting the urgent need for new therapies.

Immunotherapy Innovation and Preclinical Data

• Developed a first-in-class immunotherapy (ES2B-C001) targeting all four domains of the HER2 receptor using virus-like particle (VLP) technology.

• The vaccine elicits a broad polyclonal antibody response, outperforming monoclonal therapies and showing efficacy even in Herceptin-resistant tumors.

• Preclinical animal models showed complete tumor suppression and survival in vaccinated mice, with no adverse effects at expected dosing.

• The approach is inspired by successful VLP-based vaccines like those for HPV.

Clinical Development and Milestones

• Phase I trial is underway in metastatic HER2+ and HER2-low breast cancer; first human dosing occurred in June, with initial immune responses observed.

• Three patients have been dosed, a fourth is in screening, and preliminary safety and dosage data are expected mid-next year; interim data expected mid-2026.

• The trial includes dose escalation and expansion cohorts, with safety as the primary endpoint; Phase I-B will assess early efficacy, with full study completion targeted for end of next year.

• Phase II proof-of-concept study could begin after Phase I, involving 300–600 patients, with potential for early licensing or conditional approval.

• Registration and launch are projected for 2032–2033, with licensing targeted after Phase I or II.