NCT05232916 · Greenwich LifeSciences, Inc.
Phase 3 Study to Evaluate the Efficacy and Safety of HER2/Neu Peptide GLSI-100 (GP2 + GM-CSF) in HER2/Neu Positive Subjects
(FLAMINGO-01)
What this study is about
This is a forward-looking, randomly assigned, double-blinded, compared against an inactive treatment, multi-center, Phase 3 study of GLSI-100 immunotherapy in HLA-A\*02 positive and HER2/neu positive subjects who are at high risk for disease recurrence and have completed both neoadjuvant and postoperative adjuvant the usual treatment therapy.
View original scientific description
This is a prospective, randomized, double-blinded, placebo-controlled, multi-center, Phase 3 study of GLSI-100 immunotherapy in HLA-A\*02 positive and HER2/neu positive subjects who are at high risk for disease recurrence and have completed both neoadjuvant and postoperative adjuvant standard of care therapy. Treatment consists of 6 intradermal injections, Primary Immunization Series (PIS), over the first 6 months of treatment and 5 booster intradermal injections spaced 6 months apart.
Interventions
BIOLOGICAL
Placebo
0.9% Normal Saline
BIOLOGICAL
GLSI-100
500 mcg/mL GP2 and 125 mcg/mL GM-CSF
Primary outcome measures
Invasive Breast Cancer-free Survival (IBCFS)
Time frame: Median 4 years of follow-up (interim analysis planned)
IBCFS is defined as the time from the first dose of study medication until the date of ipsilateral invasive breast cancer recurrence, ipsilateral local-regional invasive breast cancer recurrence, distant recurrence, contralateral invasive breast cancer, or any cause mortality.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- HLA-A\*02-positive, unless being enrolled in the third non-HLA-A\*02 arm
- Histologically confirmed diagnosis of HER2/neu positive primary breast cancer for all tumors biopsied (multifocal, multicentric, or synchronous contralateral disease)
- Completion of both neoadjuvant and adjuvant trastuzumab-based standard of care breast cancer therapy
- Stage I, II, or III at presentation with pathologic evidence of residual invasive carcinoma in the breast or axillary lymph nodes (residual disease) at surgery following completion of neoadjuvant therapy -OR- Stage III at presentation with pathologic complete response (pCR) at surgery following completion of neoadjuvant therapy
- The subject can begin study therapy within one year of completion of adjuvant trastuzumab-based therapy and any other standard therapies, but, study therapy can be administered concurrently with endocrine therapy.
- No clinical evidence of residual or persistent breast cancer per treating physicia
Where
- Mobile, Alabama
- Goodyear, Arizona
- Tucson, Arizona
- Duarte, California
- Fullerton, California
- Irvine, California
- La Jolla, California
- Los Angeles, California
- Palo Alto, California
- San Francisco, California
- Santa Monica, California
- Whittier, California
And 35 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 4, 2026 · Source of record for eligibility and locations