A Randomized, Multicenter, Placebo-controlled, Phase 3 study to Evaluate the Efficacy and Safety of HER2/neu Peptide GLSI-100 (GP2 + GM-CSF) in HER2/neu Positive Subjects with Residual Disease or High-Risk PCR after both Neoadjuvant and Postoperative Adjuvant Trastuzumab-based Therapy (FLAMINGO-01)

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Greenwich LifeSciences Inc.

Participant type

Patients

Age range

18-64 years, 65+ years

Gender

Male and Female

Therapeutic area

Diseases [C] - Neoplasms [C04]

Trial duration

19 Mar 2024 → ongoing

Decision date (initial)

2025-09-29

Transition trial

No

Low-intervention

No

Rare-disease indication

No

Vulnerable population

No

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Efficacy

To assess the efficacy of GLSI-100 compared to placebo in subjects with HER2/neu positive breast cancer who have a high risk of disease recurrence (stage I, II, or III at presentation with residual disease at surgery or stage III at presentation with pathologic complete response [pCR] at surgery) and have completed both neoadjuvant and postoperative adjuvant trastuzumab-based standard of care therapy.

Secondary objectives 1

1. To assess the key secondary measures of efficacy. IBCFS and IDFS, in the study population and in important subgroups: - IBCFS in subgroup of subjects with an HLA-A*02 allele; - IBCFS in subgroup of subjects without an HLA-A*02 allele; - IDFS in the study population; - IDFS in subgroup of subjects with an HLA-A*02 allele; - IDFS in subgroup of subjects without an HLA-A*02 allele; • To assess secondary measures of efficacy, DDFS and Overall Survival, in the study populations and important subgroups (subjects with and without an HLA-A*02 allele). • To assess changes in quality of life as assessed by the EORTC Core Quality of Life questionnaire (QLQ-C30) and FACT-GP5. • To assess the safety and tolerability of GLSI-100 in the study population.

Conditions and MedDRA coding

breast cancer

Regulatory references

Plan to share IPD

Yes

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 10

1. Aged > 18 years
2. Negative pregnancy test or evidence of post-menopausal status
3. If of childbearing potential, willing to use a form of highly effective contraception
4. Histologically confirmed diagnosis of HER2/neu positive primary breast cancer
5. Completion of both neoadjuvant and adjuvant trastuzumab-based standard of care breast cancer therapy
6. 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
7. 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. Concurrent neratinib is prohibited.
8. No clinical evidence of residual or persistent breast cancer
9. ECOG 0-2
10. Adequate organ function

Exclusion criteria 10

1. Stage IV cancer or metastatic breast cancer at any time
2. Inflammatory breast cancer
3. Receiving other investigational agents
4. Receiving chemotherapy
5. Requiring long-term systemic treatment with corticosteroids or other immunosuppressive therapy
6. History of immunodeficiency or active autoimmune disease
7. A history of serious allergic reactions, including anaphylaxis, to human granulocyte-macrophage colony-stimulating factors such as sargramostim, yeast-derived products, or any component of the investigational product
8. Other malignancies except adequately treated in situ carcinoma of the cervix or basal cell or squamous cell carcinoma of the skin
9. Active infection
10. Known HIV infection with a detectable viral load within 6 months of the anticipated start of treatment. Note: Subjects on effective antiretroviral therapy with an undetectable viral load for a minimum of 6 months of the anticipated start of treatment are eligible for this trial

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 1

1. IBCFS is defined as the time from randomization (or first dose of study medication if in the non-randomized arm) 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.

Secondary endpoints 5

1. IDFS is defined as the time from randomization (or first dose of study medication if in the non-randomized arm) until the date of ipsilateral invasive breast cancer recurrence, ipsilateral local-regional invasive breast cancer recurrence, distant recurrence, contralateral invasive breast cancer, second primary non-breast invasive cancer, or any cause mortality.
2. The overall survival (OS) in the study population as defined as the time from randomization (or first dose of study medication if in the non-randomized arm) until death from any cause.
3. Quality of life as assessed by QLQ-C30 and FACT-GP5.
4. The frequency of adverse events (AEs) and serious adverse events (SAEs) characterized by type, severity (as defined by the NIH CTCAE, version 5.0), seriousness, duration, and relationship to study treatment.
5. Exploratory Endpoints: • Immune response will be measured by Delayed-Type Hypersensitivity (DTH) tests and immunologic assays. • Safety, efficacy, and immune response as defined above in non-HLA-A*02 breast cancer subjects

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 2

Placebo 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Greenwich LifeSciences Inc.

Sponsor organisation

Greenwich LifeSciences Inc.

Address

2311 Spartan Trail

City

Sugar Land

Postcode

77479-3341

Country

United States

Scientific contact point

Organisation

Greenwich LifeSciences Inc.

Contact name

Snehal Patel

Public contact point

Organisation

Greenwich LifeSciences Inc.

Contact name

Snehal Patel

Third parties 5

Locations

10 EU/EEA countries · 136 investigational sites

By country

Investigational sites

Country notifications

Trial-start, recruitment-start, end and early-termination notifications submitted per Member State

Oversight and notifications

Regulatory notifications under CTR Articles 38, 52, 53, 54 and 77

Serious breaches 1 · Art. 52 CTR

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 87 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

14 submissions — initial application plus substantial / non-substantial modifications