Greenwich LifeSciences (GLSI) Corporate presentation summary

Program and trial status

• GLSI-100 combines GP2, a 9-amino-acid HER2/neu peptide, with GM-CSF; planned dosing is 11 intradermal injections over 3 years after standard treatment.

• FLAMINGO-01 is a Phase III safety and efficacy trial in HER2-positive patients with residual disease or high-risk pCR; approximately 180 US and European sites are active.

• The revised design combines HLA types in randomized enrollment, targets the first interim analysis at 28 events with design HR 0.55, adds a second interim analysis, and allows enrollment up to 2,000 patients.

• The 250-patient non-HLA-A*02 open-label arm is fully enrolled; preliminary Q1 2026 analysis after the primary immunization series indicated a 70-80% lower recurrence rate, with HR 0.2-0.3 by different methods; data remain early and are maturing.

Clinical evidence and safety

• In Phase IIb HER2 3+ patients completing the primary immunization series, 5-year DFS was 100% with GP2 versus 89.4% with placebo; the GP2 group had no metastatic breast cancer recurrences.

• Phase IIb data showed peak immunity after 6 months; across completed trials, 146 GP2-treated patients had no SAEs attributable to GP2.

• In paired non-HLA-A*02 open-label data, DTH reactions increased from 5.2% at baseline to 20.4% at month 4 or 6 (n=191; p<0.001), indicating an immune response across HLA types in this preliminary analysis.

• In the Phase IIb safety analysis, most adverse events were grade 1; no serious adverse events were considered related to study medication.

Commercial opportunity and development

• The initial US and EU indication is estimated to address approximately 88,000 potential new patients annually, based on 12.5% of 700,000 new breast cancer patients per year.

• Broadening development across HLA types is framed as potentially doubling the GLSI-100 market, with potential annual revenue of $10 billion.

• Further development opportunities include HER2-low breast cancer, other HER2-expressing cancers, neoadjuvant treatment, and combinations with checkpoint inhibitors.

• FDA Fast Track designation was granted; commercial manufacturing commenced, and issued patents provide protection through 2032 in major markets.