ExpreS2ion Biotech (EXPRS2) Investing in Life Science 2025 summary

Disease landscape and unmet need

• Breast cancer affects 2.3 million women annually, with 685,000–700,000 deaths, projected to rise to 3 million cases and 1 million deaths by 2040.

• Incidence in women under 50 has increased by nearly 80% since 1990, with rising global incidence.

• HER2-expressing tumors are present in 80% of cases; up to 50% relapse due to drug tolerance or resistance to current therapies.

Therapeutic innovation and clinical data

• Developed a virus-like particle (VLP) immunotherapy targeting all four extracellular domains of HER2, aiming for a broader, polyclonal immune response.

• Preclinical studies show robust antibody responses, tumor inhibition, metastasis prevention, and durable effects in resistant breast cancer models.

• In mice, vaccine with adjuvant led to 100% tumor-free survival over their lifespan.

• Initial phase I human data show significant HER2-specific antibody increase in the first patient; further patient data is pending.

Development timeline and milestones

• Full treatment curve for first patient expected by December; phase I-A safety and dosage data by mid-2026.

• Phase I-B to conclude by end of next year with early efficacy data from 27 patients.

• Phase II proof-of-concept in breast cancer is planned, with potential expansion to gastric cancer.

• Licensing opportunities may arise as early as 2028, with a target launch projected for 2032–2035, potentially after phase II.