On December 9, 2020 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, reported the publication of a poster for the GP2 Phase IIb clinical trial final efficacy analysis at the San Antonio Breast Cancer Symposium in a virtual format (Press release, Greenwich LifeSciences, DEC 9, 2020, View Source [SID1234572537]). The CEO of Greenwich LifeSciences, Snehal Patel, also recorded an audio track providing an overview. The full poster with figures, tables, and audio can be accessed or downloaded here on the Company website, as well as on the conference website by attendees.

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The poster presents the final 5 year follow-up disease-free survival curves evaluating the reduction of breast cancer recurrences for both HER2/neu 3+ (Figure 1) and HER2/neu 1-2+ (Figure 2) patient populations, including the demographics (Table 1) for stage of cancer, hormone receptor status, node status, and prior treatment with chemotherapy, radiation, endocrine therapy, or trastuzumab (Herceptin).

Mr. Patel commented, "The poster presented at the SABCS is important because the Kaplan Meier survival curves and demographic data further validate our promising HER2 3+ Phase IIb data and support our plan to commence a Phase III trial in 2021. Recurring breast cancer affects 1 in 8 women. Approximately 50% of women with recurring breast cancer do not respond to Herceptin or Kadcyla, resulting in metastatic breast cancer and a poor prognosis. Approximately 80-85% of metastatic breast cancer patients do not survive. By addressing this unmet need, GP2 may reach a potential market exceeding $5 billion."

The conclusions of the poster are as follows:

‒ The trial met all of its clinical endpoints for HER2/neu 3+ patients, concluding that the first 6 intradermal injections of GP2+GM-CSF safely elicited a potent immune response and reduced recurrence rates to 0% in HER2/neu 3+ patients, who received a standard course of Herceptin after surgery. This reduction of recurrence rate was maintained over the gold standard of 5 years of follow-up. A pivotal Phase III trial is being initiated to treat HER2/neu 3+ patients in the neoadjuvant setting.

‒ GP2 may also be effective when administered in combination with Herceptin based therapeutics in HER2/neu 1-2+ patient populations or other HER2/neu expressing cancers.

Excerpts of the poster are below:

Poster PS10-23: San Antonio Breast Cancer Symposium Poster Presentation of Median 5 Year Top-Line Data

The median 5 year top-line data described below was presented at the San Antonio Breast Cancer Symposium in a poster on December 9, 2020, entitled "Five year median follow-up data from a prospective, randomized, placebo-controlled, single-blinded, multicenter, Phase IIb study evaluating the reduction of recurrences using HER2/neu peptide GP2+GM-CSF vs. GM-CSF alone after adjuvant trastuzumab in HER2 positive women with operable breast cancer."

The final analysis of the GP2 prospective, randomized, placebo-controlled, single-blinded, multicenter Phase IIb trial investigating 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) is now complete with 5 year follow-up. The trial enrolled HLA-A02 patients randomized to receive GP2+GM-CSF versus GM-CSF alone. The trial’s primary objective was to determine if treatment with GP2, a HER2-derived peptide, reduces recurrence rates.

Each enrolled and consented subject was randomized and scheduled to receive a total of 6 GP2+GM-CSF (500 mcg GP2:125 mcg GM-CSF) or placebo (125 mcg GM-CSF alone) intradermal injections every 3-4 weeks as part of the Primary Immunization Series ("PIS") for the first 6 months and 4 GP2+GM-CSF booster or placebo intradermal injections every 6 months thereafter. Boosters were introduced during the trial, thus some patients did not receive all 4 boosters.

This 168 patient (Intent to Treat, "ITT": n=180) basket trial across 16 clinical sites explored 96 HER2 3+ patients, who received a standard course of trastuzumab after surgery and subsequently completed the full PIS or placebo, starting the PIS at median 17.1 months after surgery, and 72 HER2 1-2+ patients, who did not receive trastuzumab after surgery and subsequently completed the full PIS or placebo, starting the PIS at median 10.8 months after surgery. Subject disease characteristics are described in Table 1 of the poster.

Since GP2 is synergistic with trastuzumab, and the HER2 1-2+ patients did not receive trastuzumab, it was prespecified to compare recurrence rates ITT versus per protocol in these 2 distinct, independently reported populations, excluding those patients who did not complete the PIS.

Figure 1 of the poster depicts evidence that disease free survival ("DFS") is more likely in HER2 3+ GP2-treated subjects. After 5 years of follow-up, the Kaplan-Meier estimated 5-year DFS rate in the 46 HER2 3+ patients treated with GP2+GM-CSF, 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). As shown in Table 1, the treated versus placebo HER2 3+ patients were well-matched, where approximately 53% were stage T1, 41% were stages T2-T4, 55% were node positive, 58% were hormone receptor positive and received endocrine therapy, 77% received adjuvant radiation, 77% received adjuvant chemotherapy, and 89% received trastuzumab.

GP2 was shown to be well tolerated with no SAEs and elicited a potent immune response measured by local skin tests and immunological assays, which suggest peak immunity is reached at 6 months upon completion of the PIS.

About SABCS

The 43rd 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 (AACR) (Free AACR Whitepaper) began collaborations with SABCS in 2007. For more information, please visit the conference website at: View Source

About Breast Cancer and HER2/neu Positivity

One in eight U.S. women will develop invasive breast cancer over her lifetime, with approximately 266,000 new breast cancer patients and 3.1 million breast cancer survivors in 2018. 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.