ExpreS2ion Biotech (EXPRS2) Life Science Summit 2025 summary

Disease landscape and unmet need

• Breast cancer is the most common cancer in women, with 2.3 million diagnoses and 685,000 deaths annually; incidence is rising, especially in women under 50.

• HER2-expressing tumors account for about 80% of cases, but resistance to current HER2-targeted drugs leads to high relapse rates and limited options.

• By 2040, annual breast cancer cases may exceed 3 million, with deaths potentially surpassing 1 million without new treatments.

Technology and product innovation

• ES2B-C001 is a first-in-class breast cancer vaccine using a virus-like particle (VLP) platform, displaying all four extracellular domains of HER2 for a polyclonal immune response.

• The VLP technology is validated in other vaccines (HPV, HBV) and has shown safety and strong immunogenicity in over 4,000 subjects in COVID-19 trials.

• ES2B-C001 is designed to be combinable with standard of care, scalable, and cost-effective, overcoming limitations of current monoclonal antibody therapies.

Preclinical and early clinical data

• Preclinical studies show ES2B-C001 induces broad HER2-specific antibody responses, suppresses tumor growth, and leads to tumor-free survival in resistant models.

• Vaccinated animals remained tumor-free and did not develop metastases, indicating durable protection.

• Initial human data from the first patient showed HER2-specific antibodies, breaking immune tolerance.

• First-in-human phase I trial initiated in Austria, with protocol amendment allowing enrollment at multiple centers and inclusion of patients on standard of care.

• Data safety monitoring board meeting scheduled before year-end to evaluate early patient data and advance dose escalation.