Greenwich LifeSciences Provides Update on Phase III Clinical Trial, Flamingo-01

LifeSciences Provides Update on Phase III Clinical Trial, Flamingo-01

Texas, February 14, 2024 - (Globe Newswire) - Greenwich LifeSciences, Inc.

(Nasdaq: GLSI) (the "Company"), a clinical-stage biopharmaceutical company focused on the development of GLSI-100, an immunotherapy

to prevent breast cancer recurrences in patients who have previously undergone surgery, today provided the following update on the Phase

III clinical trial, Flamingo-01.

Safety Monitoring Board (DSMB)

Flamingo-01 DSMB met twice in 2023 and recommended to continue the study as is without modification. No serious adverse events related

to GLSI-100 have been reported to date.

Clinical Sites Participating in Flamingo-01

30 clinical sites with 87 locations at multiple hospitals and the largest oncology network in the US are currently recruiting patients

and are listed below. While the first site was activated in August 2022, the first patient was screened and treated in December 2022.

Other sites enrolled their first patients in 2023 with additional sites being activated throughout the year. The Company anticipates

adding up to an additional 10 sites in 2024, bringing the total sites in the US to approximately 35-40 sites.

Clinical Sites and Networks Participating in Flamingo-01

European regulatory approval, which is expected in 2024, contracts are in place to add up to an additional 105-120 sites in Europe including

Spain (38), France (21), Germany (32), Italy (9), Poland (6), and potentially additional countries in Europe, bringing the total number

of potential sites in Flamingo-01 to approximately 140-160 sites between the US and Europe. With a peak enrollment estimate of approximately

2 - 4 patients per site per year, 150 active sites in Flamingo-01 could see peak enrollment of up to 300-600 patients per year. The logistics

to supply GP2 and Leukine labeled in each language, to collect patient samples, and to supply all other clinical supplies have been contracted

in Europe and are in the final stages of being implemented.

academic networks in each country are planning to participate in Flamingo-01 and are listed below. These networks represent the largest

oncology focused hospitals and centers in Europe, where breast cancer leaders work in a collaborative manner to help advance promising

therapies and they hold annual scientific meetings where Flamingo-01 has been introduced and where the company may present in the future.

is the leading group in breast cancer research in Spain and currently consists of more than 900 experts, who work in more than 200 centers

throughout Spain. Since its establishment in 1995, GEICAM has carried out more than one hundred studies in which more than 66,000 women

and men have participated.

or Unicancer is the federation of French comprehensive cancer centers, a major player in cancer research and a network of 20 private,

non-profit healthcare centers specialized in oncology, brought together in a health cooperation group.

Forschungs GmbH is one of the world's leading breast cancer research institutes that works together with the academic study group

German Breast Group (GBG). With more than 67,000 study participants and 3,500 new patients per year, GBG is the largest breast cancer

study group in Germany, consisting of more than 1,000 doctors in over 800 centers.

(Gruppo Italiano Mammella) is a cooperative Italian network for breast cancer research and therapy. GIM brings together over 150 participating

centers and around 500 investigators.

Update & Flamingo-01 Steering Committee

the 2023 San Antonio Breast Cancer Symposium (SABCS) and 2023 ASCO Annual Meeting, the Company met with the Flamingo-01 Steering Committee

and clinicians from the US and various countries in Europe who are participating or planning to participate in Flamingo-01.

Steering Committee is comprised of the following members:

Steering Committee discussed unpublished data, including new research the Company conducted in 2023, that suggests that GP2 may bind

to various HLA types and not just HLA-A*02, in addition to discussing the prior data that supports the third arm of the Phase III trial,

where 100 non-HLA-A*02 patients are currently planned to be enrolled. The Steering Committee agreed to expand this third arm to 250 patients.

Given the encouraging data and the Steering Committee's guidance, the Company will amend the Flamingo-01 protocol to allow up to

250 patients to enroll in the open-label arm of the study.

Rimawi, Chair of the Steering Committee, commented, "Among my peers, the level of interest in the Flamingo-01 trial is very high.

The new sites in Europe will make significant contributions to the trial in terms of patient enrollment as well as overall conduct of

the trial. The expansion of the unblinded non-HLA-A*02 arm is also significant as it reflects the interest among patients and investigators

in exploring the activity of GLSI-100 in these patients, which may expand the patient population who could benefit from this exciting

Jaye Thompson, VP Clinical and Regulatory Affairs, commented, "We

welcome the new US and European members to the Steering Committee and are honored to be receiving their continued guidance in the development

of GP2 and oversight of Flamingo-01. The Company spent considerable time in Europe in 2023 planning and organizing in each country. We

have trained the country specific research networks in each country with the assistance of the key opinion leaders of these countries

and worked closely as a group as we applied through a central European regulatory process to allow Flamingo-01 to expand into Europe.

We expect to be able to expand the third arm to 250 patients in a cost-effective manner as 85-100% of the global sites plan to enroll

into the third arm. We have also seen an increase in interest from third parties in India and China, countries with the largest prevalence

of breast cancer, who are interested in further developing GP2 for their patient populations."

the double-blinded arms of the Phase III trial, approximately 500 HLA-A*02 patients will be randomized to GLSI-100 or placebo, and up

to 250 patients of other HLA types will be treated with GLSI-100 in the third arm.

the HLA-A*02 randomized arms, the trial has been designed to detect a hazard ratio of 0.3 in invasive breast cancer-free

survival, where 28 events will be required. An interim analysis for superiority and futility will be conducted when at least half of

those events, 14, have occurred. This sample size provides 80% power if the annual rate of events in placebo-treated subjects is 2.4%

Snehal Patel commented, "With

the addition of the European sites and approximately 150 total sites, peak enrollment rates could be reached by the end of 2024 allowing

for a refinement in the interim analysis. Currently, enrollment will likely end before the interim analysis is triggered by 14 events.

However, the interim analysis could be modified such that an additional sizing interim analysis is conducted before enrollment ends to

reaffirm the size of the 2 randomized arms. While the hazard ratio of 0.3 assumes that the recurrence rate of the treated arm will be

30% of the recurrence rate in the placebo arm and thus a 70% reduction in recurrence rate, and while the Phase II trial showed even greater

reduction in recurrence rate, we are likely to see recurrences in the treated arm of the Phase III trial and have designed the trial

accordingly. Using the early Phase III trial data to reaffirm the size of the arms of the Phase III trial may be the best information

we could use to reduce risk and improve the chances of success of Flamingo-01."

Patel further added, "While

we may have high expectations for the interim analysis midway through the trial, Roche's

successful Herceptin and Kadcyla products reduced recurrences by only 50%, while still requiring that all HER2 positive patients be treated.

Thus, we believe a similar clinical outcome for Flamingo-01 could occur and could generate similar returns to stakeholders as did Roche's

franchise drugs, which at their peak significantly exceeded $5 billion in revenue per year."

for Filing of BLA in the US

addition to the submission of the Phase III clinical data, submitting commercial manufacturing data and study reports on the prior clinical

trials will be critical to the filing of a BLA for GLSI-100 and for regulatory filings in other countries.

Manufacturing: The first 3 commercial lots of GP2 active ingredient were completed and released

in 2023, representing an important step towards commercialization. The 3 lots in total could be used to prepare approximately 200,000

doses of GP2. In 2024, the first of 3 commercial lots filling GP2 into vials for commercial sale or for clinical use is planned. Data

on these commercial lots will be submitted to the FDA in the US and other regulatory agencies in Europe or elsewhere when a marketing

application is filed seeking approval to sell GP2 in these respective markets.

II Clinical Trial Study Report: The Company is preparing a comprehensive study report of the Phase II trial for the FDA prior to

the filing of a BLA. This report will include the patients with breast cancer recurrences, the last known date of patients who did not

recur (censoring data), the adverse events, immune responses, and other final study report analyses. This report will serve to complement

the Phase III data and to provide a drug product dossier that can also be submitted to regulatory agencies in other countries for marketing

approval. The use of GM-CSF as an adjuvant in GLSI-100 may also be included in the dossier as GM-CSF is only commercially available in

the US at this time.

Patel commented, "We

have experienced significant interest from investors, strategics, analysts, and regulators in the 5 year follow-up data we published

and the 3 and 4 year follow-up data independently published by the clinical investigators. The differences between these publications

can be best explained by the increased maturity of the data as each year progressed. In all 3 publications, no recurrences or a 100%

reduction in recurrence rate, were reported in the sub-population that the Flamingo-01 design has been based on and any differences between

the number of patients in the treated or placebo groups has been shown to be immaterial."

Company did not have responsibility for the conduct of the trial or for the data from the Phase II trial. After the trial had already

started, the Company received the rights to the Phase II trial data pursuant to a license agreement with the Henry Jackson Foundation

(HJF) that entitled the Company to all of the GP2 data from the Phase II trial and all prior trials, but did not provide the Company

with the ability to participate in the Phase II trial as a regulatory clinical sponsor. The lead clinicians and HJF were responsible

for project and site management, medical monitoring, data monitoring of case report forms (CRFs), correspondence with the FDA, and creation,

data entry and management of the database. The Company was provided study updates but was not provided an opportunity to participate

in any of the above activities or to review the publications of the 3 and 4 year follow-up data by the lead clinicians. Thus, the comprehensive