- Identifying GP2 specific T cell immune response at baseline
prior to treatment with GP2 has potential to predict breast cancer
recurrence risk and timing of recurrence
- A positive baseline immune response to GP2 in 22.8% of 145
patients suggests an existing immune response to GP2 associated
with residual disease, impending recurrence, or prior
treatments
- DNA sequencing of relevant GP2 specific T cells at baseline and
during GP2 treatment could lead to potential CAR-T cell drug
candidates
- Data further validates 0% metastatic breast cancer recurrence
mechanism and reaffirms that GP2 is a natural antigen that should
be the target of peptide and T cell based platform
technologies
Greenwich LifeSciences, Inc. (Nasdaq: GLSI) (the “Company”), a
clinical-stage biopharmaceutical company focused on the development
of GP2, an immunotherapy to prevent breast cancer recurrences in
patients who have previously undergone surgery, today announced the
publication of a poster for the GP2 Phase IIb clinical trial at the
San Antonio Breast Cancer Symposium 2021 (SABCS). The CEO of
Greenwich LifeSciences, Snehal Patel, recorded an audio track
providing an overview. The abstract can be viewed at the bottom of
this press release. The full poster with figures, tables, and audio
can be accessed or downloaded from the Company’s website here.
This press release features multimedia. View
the full release here:
https://www.businesswire.com/news/home/20211209005502/en/
Figures 1-2: Summary of 5 year GP2 Data
Published to Date (Graphic: Business Wire)
Figure 1 is the new data published yesterday evening at SABCS,
which shows that GP2 immune response at baseline could be a
prognosticator of cancer recurrence. The Phase IIb clinical trial
enrolled HER2 positive patients, who received a standard course of
trastuzumab after surgery, and HER2 low patients, who did not
receive trastuzumab after surgery. A Delayed-Type Hypersensitivity
(DTH) reaction was used to assess baseline in vivo immune responses
to GP2 in patients prior to exposure to GP2 treatment or
placebo.
The poster data can be summarized as follows:
‒ It was observed that 22.8% or 33 patients of the 145 patients
reacted to GP2 at baseline with a positive immune response, which
is defined as an induration of 5 mm or greater in the baseline DTH
test.
‒ Of the 33 patients who did have a
positive baseline DTH immune response to GP2, 8 patients recurred,
which is a recurrence rate of 24.2% over 5 years of follow up, with
a median time to recurrence of 99 days (0.27 years).
‒ Of the 77.2% or 112 patients who did not
have a positive DTH baseline immune response to GP2, 14
patients recurred, which is a recurrence rate of 12.5% over 5 years
of follow up, with a median time to recurrence of 438 days (1.2
years).
Mr. Patel commented, “This new GP2 specific T cell data suggests
that patients with a positive baseline immune response to GP2
recurred twice as fast and approximately 7 to 11 months sooner than
those without a positive baseline immune response did. While this
data is very promising, the number of recurrences are low, thus we
need to further confirm these observations in the upcoming Phase
III clinical trial to determine if they are statistically
significant. To further diversify our pipeline, we plan to fully
characterize GP2 specific T cells by sequencing the DNA of the T
cells at baseline and after treatment with GP2 to assess how these
T cells change over time and if they can be developed into CAR-T
drug candidates. Expansion into GP2 specific CAR-T cells could
potentially become another platform technology to complement GP2
peptide treatment in higher risk patients. We expect new T cell
data from the Phase III trial to become available in 2022.”
Today is the one year anniversary of the Company’s SABCS 2020
poster, which became the basis for Figure 2. This figure summarizes
the efficacy, immune response, and safety Phase IIb data presented
over the past year. The Kaplan Meier analysis for HER2 positive
patients treated with GP2 immunotherapy shows 100% disease free
survival (0% breast cancer recurrences, p = 0.0338) following
surgery and Herceptin treatment over median 5 years of follow-up.
These patients completed the Primary Immunization Series (PIS)
which led to peak immunity at 6 months. No serious adverse events
attributable to GLSI-100 were observed. Figure 1 and Figure 2
summarize all of the 5 year GP2 data published to date.
SABCS Abstract P2-13-29:
Title: Analysis of GP2 immune response and relationship to
recurrence in a prospective, randomized, placebo-controlled,
single-blinded, multicenter, phase IIb study evaluating the
reduction of recurrences using HER2/neu peptide GP2 (GLSI-100) vs.
GM-CSF alone after adjuvant trastuzumab in HER2 positive women with
operable breast cancer
Snehal S Patel, David B McWilliams, Mira S Patel, Christine T
Fischette, Jaye Thompson and F Joseph Daugherty.
Greenwich LifeSciences, Stafford, TX
Background: Delayed type
hypersensitivity (DTH) skin tests in the randomized,
active-controlled, single-blinded, multicenter Phase IIb trial
investigating GLSI-100 (GP2+GM-CSF) administered in the adjuvant
setting to node-positive and high-risk node-negative breast cancer
patients with tumors expressing any degree of HER2
(immuno-histochemistry [IHC] 1-3+) (NCT00524277) have been
analyzed. The trial enrolled HLA-A*02 patients randomized to
receive GLSI-100 versus GM-CSF alone. The trial's primary objective
was to determine if treatment with GLSI-100, a HER2-derived
peptide, reduces recurrence rates. Analyses for this trial showing
GLSI-100 to be efficacious, safe and immunogenic have been
previously reported by Patel et al. and Mittendorf et al.
Methods: Consented patients
were randomized and scheduled to receive GLSI-100 (500 mcg GP2: 125
mcg GM-CSF) or control (GM-CSF only) via 6 intradermal injections
every 3-4 weeks as part of the Primary Immunization Series (PIS)
for the first 6 months and 4 booster intradermal injections every 6
months thereafter. Boosters were introduced during the trial, thus
some patients did not receive all 4 boosters. DTH skin tests were
assessed at baseline and after the 6th dose with the orthogonal
mean of each skin reaction measured 48-72 hours after injection
using the sensitive ballpoint-pen method.
Results: The study enrolled
180 patients across 16 clinical sites with both HER2 3+ positive
and low HER2 expressors (1-2+). After 5 years of follow-up, the
Kaplan-Meier estimated 5-year DFS rate in the 46 HER2 3+ patients
treated with GLSI-100, if the patient completed the PIS, was 100%
versus 89.4% (95% CI:76.2, 95.5%) in the 50 placebo patients
treated with GM-CSF (p = 0.0338). GLSI-100 was shown to be well
tolerated with no SAEs deemed related to study medication and
elicited a potent immune response measured by local skin tests and
immunological assays. Injection site reactions were common,
occurring in almost 100% of patients treated with either GLSI-100
or GM-CSF alone. Previous publications have reported the increase
in DTH response reported among patients after treatment with
GLSI-100. However, it was of interest to understand the positive
DTH responses to GP2 noted at baseline. 22.8% of patients reacted
to GP2 at baseline with induration of 5mm or greater. In the
subgroup of patients who later experienced a breast cancer
recurrence, 36.4% (8/22) had such a baseline response. Analysis of
the time to recurrence among those recurring found that the median
time to recurrence was 0.6 years for those with a baseline response
while those that did not have a positive baseline DTH response to
GP2 took 1.2 years to recur.
Conclusions: This study
demonstrated that GLSI-100 safely elicited a potent immune response
as evidenced by increased DTH skin responses with treatment paired
with improved disease-free survival. It is theorized that a
positive baseline DTH skin test to GP2 may be evidence of an
existing immune response to GP2 associated with residual disease,
impending recurrence, or prior treatments. Further studies
assessing if GP2 immune response is an important prognosticator of
cancer disease state or recurrence are planned.
About SABCS
The 44th annual SABCS has grown to be the industry’s premier
breast cancer conference for basic, translational, and clinical
cancer research professionals. It is well-known for presenting the
latest breast cancer data from all over the world. More than 7,500
health care professionals from more than 90 countries attend
annually. Baylor College of Medicine became a joint sponsor of
SABCS in 2005. The Cancer Therapy & Research Center at UT
Health Science Center San Antonio and American Association for
Cancer Research began collaborations with SABCS in 2007. For more
information, please visit the conference website at:
https://www.sabcs.org/
About FLAMINGO-01 and GLSI-100
The Phase III clinical trial will be called FLAMINGO-01 and the
combination of GP2 + GM-CSF will be called GLSI-100. The Phase III
trial is comprised of 2 blinded, randomized, placebo-controlled
arms for approximately 500 HLA-A*02 patients and 1 open label arm
of up to 100 patients for all other HLA types. An interim analysis
has been designed to detect a hazard ratio of 0.3 in IDFS, 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% or greater. The
trial is currently being registered on clinicaltrials.gov and the
link and trial identifier will be published shortly. For future
updates about FLAMINGO-01 please visit the Company’s clinical trial
tab at https://greenwichlifesciences.com/clinical-trials/.
About Breast Cancer and HER2/neu Positivity
One in eight U.S. women will develop invasive breast cancer over
her lifetime, with approximately 282,000 new breast cancer patients
and 3.8 million breast cancer survivors in 2021. HER2/neu (human
epidermal growth factor receptor 2) protein is a cell surface
receptor protein that is expressed in a variety of common cancers,
including in 75% of breast cancers at low (1+), intermediate (2+),
and high (3+ or over-expressor) levels.
About Greenwich LifeSciences, Inc.
Greenwich LifeSciences is a clinical-stage biopharmaceutical
company focused on the development of GP2, an immunotherapy to
prevent breast cancer recurrences in patients who have previously
undergone surgery. GP2 is a 9 amino acid transmembrane peptide of
the HER2/neu protein. In a randomized, single-blinded,
placebo-controlled, multi-center (16 sites led by MD Anderson
Cancer Center) Phase IIb clinical trial, no recurrences were
observed in the HER2/neu 3+ adjuvant setting after median 5 years
of follow-up, if the patient received the 6 primary intradermal
injections over the first 6 months (p = 0.0338). Of the 138
patients that have been treated with GLSI-100 to date over 4
clinical trials, treatment was well tolerated and no serious
adverse events were observed related to the immunotherapy.
Greenwich LifeSciences is planning to commence a Phase III clinical
trial using a similar treatment regime as the Phase IIb clinical
trial. For more information on Greenwich LifeSciences, please visit
the Company’s website at www.greenwichlifesciences.com and follow
the Company's Twitter at https://twitter.com/GreenwichLS.
About GP2 Immunotherapy Immune Response
As previously reported, GP2 immunotherapy generated GP2-specific
immune responses, leading to no metastatic breast cancer recurrence
in the HER2/neu 3+ population in the Phase IIb clinical trial, thus
supporting GP2’s mechanism of action. Statistically significant
peak immunity was reached after 6 months of GP2 treatment, as
measured in both the Dimer Binding Assay and the DTH skin test.
HER2/neu 3+ population immune response was similar to the HER2/neu
1-2+ population immune response, suggesting the potential to treat
the HER2/neu 1-2+ population (including triple negative breast
cancer) with GP2 immunotherapy in combination with trastuzumab
(Herceptin) based products and other clinically active agents. The
broad based immune response suggests the potential for GP2 to treat
other HER2/neu 1-3+ expressing cancers. For more information on GP2
immune response and clinical data, please visit the Company’s
clinical trial tab at
https://greenwichlifesciences.com/clinical-trials/.
Forward-Looking Statement Disclaimer
Statements in this press release contain “forward-looking
statements” that are subject to substantial risks and
uncertainties. All statements, other than statements of historical
fact, contained in this press release are forward-looking
statements. Forward-looking statements contained in this press
release may be identified by the use of words such as “anticipate,”
“believe,” “contemplate,” “could,” “estimate,” “expect,” “intend,”
“seek,” “may,” “might,” “plan,” “potential,” “predict,” “project,”
“target,” “aim,” “should,” "will,” “would,” or the negative of
these words or other similar expressions, although not all
forward-looking statements contain these words. Forward-looking
statements are based on Greenwich LifeSciences Inc.’s current
expectations and are subject to inherent uncertainties, risks and
assumptions that are difficult to predict, including statements
regarding the intended use of net proceeds from the public
offering; consequently, actual results may differ materially from
those expressed or implied by such forward-looking statements.
Further, certain forward-looking statements are based on
assumptions as to future events that may not prove to be accurate.
These and other risks and uncertainties are described more fully in
the section titled “Risk Factors” in the final prospectus related
to the public offering filed with the SEC. Forward-looking
statements contained in this announcement are made as of this date,
and Greenwich LifeSciences, Inc. undertakes no duty to update such
information except as required under applicable law.
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version on businesswire.com: https://www.businesswire.com/news/home/20211209005502/en/
Company Contact Snehal Patel Investor Relations Office:
(832) 819-3232 Email: info@greenwichlifesciences.com
Investor & Public Relations Contact for Greenwich
LifeSciences Dave Gentry RedChip Companies Inc. Office:
1-800-RED CHIP (733 2447) Cell: (407) 491-4498 Email:
dave@redchip.com
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