# GLSI-100

Source: https://onco.cc/drugs/glsi-100/  
OnCo record `glsi-100` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

GLSI-100 is an experimental cancer vaccine from Greenwich LifeSciences in phase 3 trials for HR-positive / HER2-negative breast cancer, aimed at HER2.

## Summary

GLSI-100 is a cancer vaccine developed by Greenwich LifeSciences. Its target is HER2 (the sponsor names HER2/neu). The sponsor states: Combines GP2, a nine-amino-acid HER2/neu-derived transmembrane peptide, with the immunoadjuvant GM-CSF to prime and expand HER2/neu-specific CD8+ cytotoxic T lymphocytes that recognise and destroy HER2/neu-expressing cancer cells, aiming to prevent breast cancer recurrence. It is the investigational product in 1 recruiting or active industry-led phase 2 and phase 3 interventional cancer trial, including the phase 3 study NCT05232916 (Phase 3 Study to Evaluate the Efficacy and Safety of HER2/Neu Peptide GLSI-100 (GP2 + GM-CSF) in HER2/Neu Positive Subjects), in HR-positive / HER2-negative breast cancer. The largest, NCT05232916, plans to enrol 2250 participants with primary completion expected 2031-12. Status reflects the highest phase registered on ClinicalTrials.gov; no efficacy results are recorded here.

## Fields

- Kind: Treatment
- Status: phase-3
- Last checked: 2026-09-11
- Tags: pipeline; ctgov-ingest
- Modality: vaccine
- Mechanism: Combines GP2, a nine-amino-acid HER2/neu-derived transmembrane peptide, with the immunoadjuvant GM-CSF to prime and expand HER2/neu-specific CD8+ cytotoxic T lymphocytes that recognise and destroy HER2/neu-expressing cancer cells, aiming to prevent breast cancer recurrence.

## Sources

- ClinicalTrials.gov: trials of GLSI-100: https://clinicaltrials.gov/search?intr=GLSI-100
- Sponsor pipeline page: https://greenwichlifesciences.com/gp2/

## Connected records

- cancers: [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/)
- targets: [HER2](https://onco.cc/targets/her2/)
- companies: [Greenwich LifeSciences](https://onco.cc/companies/greenwich-lifesciences/)
- trials: [Phase 3 Study to Evaluate the Efficacy and Safety of HER2/Neu Peptide GLSI-100 (GP2 + GM-CSF) in HER2/Neu Positive Subjects](https://onco.cc/trials/nct05232916/)

---
JSON: https://onco.cc/api/v1/entities/glsi-100.json