Greenwich Lifesciences, Inc. · NASDAQ:GLSI

Greenwich Lifesciences — Investor Presentation (September 2026)

41 slides from Greenwich Lifesciences's investor presentation, September 2026

  1. Slide 1: Greenwich LifeSciences Corporate Presentation

    GREENWICH LIFESCIENCES Planned GLSI-100 (GP2 + GM-CSF) Phase III Clinical Trial, FLAMINGO-01 A Breakthrough Targeted Immunotherapy to Prevent Breast Cancer Recurrences NASDAQ: GLSI Snehal Patel, CEO © 2026 GLSI Image: T-cells targeting cancer cell

  2. Slide 2: Safe Harbor Statement

    Safe Harbor Statement This document is the property of Greenwich LifeSciences, Inc., (the “Company” or “Greenwich LifeSciences”). This document is non-directive in nature (contains no recommendations regarding financial actions related to the Company). This document is not to be copied or delivered

  3. Slide 3: GLSI-100 (GP2 + GM-CSF) Executive Summary

    GLSI-100 (GP2 + GM-CSF) Executive Summary • Flamingo-01 - Current Phase III Trial with Interim Analysis: 9 amino acid HER2/neu peptide + GM-CSF immunotherapy for breast cancer in HER2/neu positive patients following neoadjuvant, surgery, & adjuvant Herceptin or Kadcyla, led by Baylor & consortium of

  4. Slide 4: First Year Share Price Performance After Presenting Key Phase IIb Data

    First Year Share Price Performance After Presenting Key Phase IIb Data in 2020/2021 • Raised approximately $36.5M from IPO & Follow-on in 2020 • Peak share prices and trading volume driven by data publications • 30x or 2,940% return from intraday high on 12/9/20, possibly highest intraday return for

  5. Slide 5: 2020-2021 Four Posters Highlighting Efficacy, Mechanism, Safety

    2020-2021 - Four Posters Highlighting Efficacy, Mechanism of Action, Safety, & Prognostic Factors 2020 San Antonio Breast Cancer Symposium (SABCS) 2021 American Association for Cancer Research (AACR) 0% Recurrences Over 5 Years in Phase IIb Trial Immune Response Supports Mechanism of Action 2021 Ame

  6. Slide 6: 5 Year Data Set of GP2 Phase IIb Trial is Complete

    5 Year Data Set of GP2 Phase IIb Trial is Complete HER2 3+ (Positive) Patients who Completed the Primary Immunization Series (PIS) 100% Disease Free Survival, 0% Metastatic Breast Cancer Recurrences** Peak Immunity After 6 Months & PIS Injection Site & Systemic Adverse Events (AE) are Positive Sign

  7. Slide 7: ASCO 2021 – Systemic & Injection Site Reactions

    ASCO 2021 – Systemic & Injection Site Reactions Figure 2: Incidence of Maximum Severity Grade Adverse Events The maximal severity grade for any AE, systemic and injection site reaction, for each patient was identified. There was no difference between the two treatment arms, as presented in Figure 2.

  8. Slide 8: ASCO 2021 – Incidence of Adverse Events

    ASCO 2021 – Incidence of Adverse Events Tables 1 & 2: Incidence of Adverse Events The first occurrence of frequently reported AEs is tabulated in Table 1. The most common AE was injection site reaction. Almost every patient, in both the GP2+GM-CSF and GM- CSF only arms, reported injection site react

  9. Slide 9: 6 Year Performance Since IPO – Planning & Initiation of Phase III Trial

    6 Year Performance Since IPO – Planning & Initiation of Phase III Trial in up to 180 sites in 10 Countries 2022 – 2026 Events • Major KOLs joined Steering Committee • 35-40 US sites initiated in 2023-2024 • Large academic networks added • EMA approved 105-120 sites in 2024-2025 • Total up to 180 sit

  10. Slide 10: Flamingo-01 Steering Committee

    Flamingo-01 Steering Committee The Steering Committee is comprised of the following members : • Dr. Mothaffar F. Rimawi – Professor of Medicine at the Baylor College of Medicine • Dr. Francois-Clement Bidard – Professor of Medical Oncology, UVSQ/Paris Saclay University, Head of Breast Cancer Group,

  11. Slide 11: Flamingo-01 Clinical Site Map – Up to 180 sites in US/EU

    Flamingo-01 Clinical Site Map – Up to 180 sites in US/EU Participating networks: USOncology/Sarah Cannon, TRIO-US, GEICAM (Spain), Unicancer (France), GBG (Germany), GIM (Italy) Potential additions: Canada, United Kingdom © 2026 GLSI 11

  12. Slide 12: Breast Cancer – Still a Substantial Unmet Need

    Breast Cancer – Still a Substantial Unmet Need • Unmet Need is to address the 50% of recurring patients who do not respond to Herceptin or Kadcyla – an opportunity for GP2. • Adjuvant Setting: Following breast cancer surgery, HER2/neu 3+ patients receive Herceptin in the first year and then hope tha

  13. Slide 13: GP2 Phase III Clinical Trial Dosing

    GP2 Phase III Clinical Trial Dosing Potential Data Read Out: Interim analysis planned after ½ of prescribed events have occurred 1 year 1 year Surgery GP2 – 11 doses over 3 years Primary Immunization Series (6 Doses) Boosters (5 Doses) Doses Months 0 1 2 3 4 5 6 12 18 24 30 36 Immunologic X X X X X

  14. Slide 14: GP2 Market Positioning & Feedback from KOLs

    GP2 Market Positioning & Feedback from KOLs • As only injection site reactions were observed (which speaks to the immunogenicity of GP2) and with no SAEs attributable to GP2, GP2 can be positioned as the final treatment for patients post surgery • Patients are seeking a de-escalation and a return to

  15. Slide 15: Synergy with Herceptin Alone

    ** 5 Year Disease Free Survival Synergy with Herceptin Alone ** without use of Kadcyla, Perjeta, Nerlynx, Enhertu, or Tukysa Herceptin Approved for Adjuvant Treatment of HER2/neu 3+ Breast Cancer Phase IIb Results for GP2 Target Population, if Fully Immunized (median 5 years follow-up) 100.0% 89.4%

  16. Slide 16: GP2 Clinical Data: GP2 is Immunogenic & Clinically Effective

    GP2 Clinical Data: GP2 is Immunogenic & Clinically Effective 16 © 2026 GLSI

  17. Slide 17: HER2/neu Signaling Pathway Well Studied

    HER2/neu Signaling Pathway Well Studied ➢ HER2/neu pathway activates cancer cell proliferation ➢ Overexpression of HER2/neu correlates strongly with aggressive cancers 3D Structure of HER2/neu Protein GP2 Peptide © 2026 GLSI 17

  18. Slide 18: GP2 Product Description & Mechanism of Action

    GP2 Product Description & Mechanism of Action • 9 amino acid transmembrane peptide segment of HER2/neu protein • Intradermal injection in combination with an FDA-approved immunoadjuvant GM-CSF, following 1st year of Herceptin treatment in Adjuvant Setting 5 -15° angle • Given once per month for six

  19. Slide 19: Summary of GP2 Completed Trials

    Summary of GP2 Completed Trials - N=146 GP2-Treated Patients to Date with No SAEs Attributable to GP2 Design and Number of Duration of Study Product, Dose, and Route Regimen Population Control Subjects Follow-Up 3x3 Dose- • GP2 at 100, 500, 1000mcg 6 doses, every 18 • Breast cancer Primary safety Ph

  20. Slide 20: GP2 Phase III Trial – FLAMINGO-01: Strategy

    GP2 Phase III Trial – FLAMINGO-01: Strategy – Conservatively Reproduce Phase IIb Trial in Larger Population © 2026 GLSI 20 20 © 2026 GLSI

  21. Slide 21: Flamingo-01 - Phase III Trial

    Flamingo-01 - Phase III Trial Flamingo-01 • Approximately 180 sites are active • Flamingo-01 is evaluating the safety and efficacy of GLSI-100 (GP2 + GM-CSF) in HER2/neu positive breast cancer patients who had residual disease or high- risk pathologic complete response at surgery • What is next – tr

  22. Slide 22: Flamingo-01 - Phase III Trial Schema

    Flamingo-01 - Phase III Trial Schema Phase III Trial Schema Interim Analysis Design Major Screening Criteria: Stratified by: New Interim Design: • HER2/neu 3+ and HLA type • Residual disease/pCR • Combining all new patients • Residual disease • Hormone receptor status into one randomized arm • pCR i

  23. Slide 23: Derisked Phase III Trial

    Derisked Phase III Trial The Phase III clinical trial has been derisked by: • Increasing the size of the study, which would increase the power of the study thus decreasing the risk by designing the study to assume more recurrences with a higher HR even though fewer recurrences may be anticipated and

  24. Slide 24: New Design May Double the Market for GLSI-100

    New Design May Double the Market for GLSI-100 Commercial benefits of combining all non-HLA-A*02 and HLA-A*02 patients into blinded arms: • The study is now designed and sized to improve the probability of success, to attract the interest of sophisticated investors and pharma companies, and to maximi

  25. Slide 25: FLAMINGO-01 - Hallmarks of a Large Pharma Phase III Trial

    FLAMINGO-01 - Hallmarks of a Large Pharma Phase III Trial Comparison of FLAMINGO-01 to Katherine (Kadcyla) and Destiny Breast-05 (Enhertu): • By doubling the number of events to trigger an interim and increasing the HR to 0.55, which is offset by the more than doubling event rate due to the higher e

  26. Slide 26: Non-HLA-A*02 Open Label Poster at AACR 2026

    Non-HLA-A*02 Open Label Poster at AACR 2026 by Steering Committee © 2026 GLSI 26

  27. Slide 27: Non-HLA-A*02 Open Label Poster at ASCO 2026

    Non-HLA-A*02 Open Label Poster at ASCO 2026 by Steering Committee © 2026 GLSI 27

  28. Slide 28: Comparing Non-HLA-A*02 Data to Phase IIb Study

    Comparing Non-HLA-A*02 Data to Phase IIb Study Preliminary Flamingo-01 data available in Q1 2026 is summarized in a blinded manner. This summary may not reflect results at the end of the study. • 250 patient non-HLA-A*02 arm is now fully enrolled - all patients received GLSI-100, which is 5 times mo

  29. Slide 29: Expand by HLA - GP2-HLA Observed & Predicted Prevalence

    Expand by HLA - GP2-HLA Observed & Predicted Prevalence Preliminary Flamingo-01 data available to date is summarized in a blinded manner. This summary may not reflect results at the end of the study. • Across all screened patients, HLA-A*02 prevalence is about 46%. The double HLA-A*02 prevalence, in

  30. Slide 30: GP2 May Address Unmet Need in Adjuvant & Neoadjuvant Settings

    GP2 May Address Unmet Need in Both HER2/neu 3+ Adjuvant & Neoadjuvant Settings Surgery Surgery Projected 5 Year Recurrence Rates 9-12% 9-12% 5-10% 17% 5-10% 17% Conclusion: GP2 should eventually be pursued in Target Population for Phase III Trial: Residual Disease both settings for all HER2 & High R

  31. Slide 31: GP2 Specific & Secondary Immune Response TCR Sequencing

    GP2 Specific & Secondary Immune Response TCR Sequencing Multiple Open Label Immune Response Assessments are Planned to Potentially Identify GP2 Specific T cells, Biomarkers, Booster Strategies, and Early Recurrers 1. Delayed Type Hypersensitive (DTH) skin test for in vivo immune response to GP2 (20%

  32. Slide 32: GP2 Commercial Opportunity

    GP2 Commercial Opportunity © 2026 GLSI 32 © 2026 GLSI

  33. Slide 33: Potential Indications of GP2 & Herceptin in Neoadjuvant Setting

    Potential Indications of GP2 & Herceptin in Various Populations in Neoadjuvant Setting • HER2/neu 3+ protein over-expression (25%) & True Negative 25% 1-2+ expression (50%) HER2/neu 1-2+ – All breast cancer patients are tested for HER2/neu 50% expression by immunohistochemistry (IHC) or HER2/neu 3+

  34. Slide 34: Commercial Opportunity for GP2 in Breast Cancer in US/EU

    Commercial Opportunity for GP2 in Breast Cancer in US/EU • 1 in 8 U.S. women (12.8%) will develop invasive breast cancer over her lifetime, with 317k new breast cancer patients per year in 2025 (400k in EU) • An estimated 42k female breast cancer deaths will occur in the US in 2025 • GP2’s target ma

  35. Slide 35: Potential Additional Indications for GP2

    Potential Commercial Opportunities / Additional Indications for GP2: HER2/neu Expressed in Multiple Cancers Denotes cancers where HER2/neu over expression has been reported © 2026 GLSI 35

  36. Slide 36: Veteran Management Team / Board

    Veteran Management Team / Board • David McWilliams, MBA – Chairman, Board – 40 years of start-up / CEO experience – CEO of 2 private and 3 public biotech companies indexCopy_01 • Snehal Patel, MS, MBA – CEO, Board – 30 years of biopharma / Wall Street experience – Large pharma operations / managemen

  37. Slide 37: Manufacturing / Regulatory / IP

    Manufacturing / Regulatory / IP • GP2 manufactured by straightforward amino acid chemistry – Manufactured by FDA-approved commercial facility with multiple back-up facilities – Commercial manufacturing commenced – 3 clinical lots followed by 3 commercial lots – GM-CSF is commercially available, alon

  38. Slide 38: GLSI Strategy is to Conduct Additional GP2 Trials

    GLSI Strategy is to Conduct Additional GP2 Trials Greenwich’s current strategy is as follows: • Reproduce Phase IIb trial in Add Checkpoint Inhibitors Phase III trial in HER2 positive patients only – no material changes to treatment regimen, upgrade immune response assays, expand to multiple HLA typ

  39. Slide 39: GP2 Conclusions: A Breakthrough Targeted Immunotherapy

    GP2 Conclusions: A Breakthrough Targeted Immunotherapy for Prevention of HER2/neu Cancer • Flamingo-01 - Current Phase III Trial with Interim Analysis: 9 amino acid HER2/neu peptide + GM-CSF immunotherapy for breast cancer in HER2/neu positive patients following neoadjuvant, surgery, & adjuvant Herc

  40. Slide 40: GLSI Sponsorship of 5k Race in Houston each October

    GLSI Sponsorship of 5k Race in Houston each October © 2026 GLSI 40

  41. Slide 41: For Additional Information, Please Contact

    NASDAQ: GLSI For Additional Information, Please Contact: Snehal Patel CEO Telephone: 832.819.3232 E-mail: [email protected] Website: greenwichlifesciences.com © 2026 GLSI

Greenwich LifeSciences — Investor Presentation (September 2026) on 6ix