Seres Therapeutics, Inc. · NASDAQ:MCRB

Seres Therapeutics — Investor Presentation (September 2024)

30 slides from Seres Therapeutics's investor presentation, Sep 12, 2024

  1. Slide 1: Seres Therapeutics Investor Presentation

    Exhibit 99.3 Seres Therapeutics Investor Presentation September 12, 2024

  2. Slide 2: Disclaimers: Forward Looking Statements

    Disclaimers Forward Looking Statements This communication contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this communication that do not relate to matters of historical fact should be considered forward-looki

  3. Slide 3: Disclaimers: Important Information About the Transaction

    Disclaimers Important Information About the Transaction and Where to Find it In connection with the proposed transaction involving Seres Therapeutics, Inc. (“Seres”) and Société des Produits Nestlé S.A. (“SPN”), Seres filed a definitive proxy statement with the Securities and Exchange Commission (th

  4. Slide 4: September 2024: SER-155 Phase 1b placebo-controlled cohort study results in allo-HSCT

    September 2024: SER-155 Phase 1b placebo-controlled Cohort 2 study results in allo-HSCT • Phase 1b study in adults undergoing allogeneic hematopoietic stem cell transplant (allo-HSCT) to assess SER-155 safety and pharmacology, with additional endpoints such as incidence of bacterial bloodstream infe

  5. Slide 5: Transforming patient outcomes using proprietary consortia of live biotherapeutics

    Transforming patient outcomes using proprietary consortia of live biotherapeutics Strong foundation Favorable Phase 1b Blockbuster opportunity Expansive potential clinical data in SER- • Validated platform with • Accelerate SER-155 • SER-147 designed to ® 155 allo-HSCT VOWST clinical and development

  6. Slide 6: Validated platform: Seres pioneered the development and FDA approval of VOWST

    Validated platform: Seres pioneered the development and FDA approval of VOWST as the first-ever oral live microbiome therapeutic DRAMATIC CLINICAL BENEFIT – Preventing infection recurrence Approximately 88% FDA approved (April 2023) sustained clinical response rate to prevent the recurrence of (C. d

  7. Slide 7: VOWST asset sale a transformational transaction for Seres

    VOWST asset sale a transformational transaction for Seres KEY FINANCIAL TERMS $100M upfront payment to Seres, less ~$20M in net obligations due to an affiliate of SPN* • VOWST asset purchase agreement $15M equity investment by SPN at closing provides infusion of capital and $60M prepaid sales-based

  8. Slide 8: Potential to treat a range of vulnerable patient populations

    Potential to treat a range of vulnerable patient populations Potential to prevent bacterial infections and Target population characteristics immune-related disease Prevent life-threatening infections (current focus) GI microbiome Immune • Blood cancers (including HSCT, CAR-T) functional suppression

  9. Slide 9: GI microbiome functional disruption leads to disease susceptibility

    GI microbiome functional disruption leads to disease susceptibility GI Microbiome: Healthy Functionally disrupted IMPACTED BIOLOGY • Pathogen domination • Lost barrier & mucosal integrity • Unfavorable immune responses Commensal microbes Pathogenic microbes Seres Therapeutics, Inc. © 2024 9

  10. Slide 10: Seres' biotherapeutics designed to restore functionality and health

    Seres’ biotherapeutics designed to restore functionality and health Bacteria engraft and restructure GI microbiome, restoring critical biology Formulated for oral administration Cultivated in Pathogen inhibition Seres labs from master cell banks Bacteria selected based on desired functional Barrier

  11. Slide 11: Well tolerated safety profile, reducing development risk

    Seres’ biotherapeutics and pipeline candidates have well tolerated safety profile, reducing development risk ✓Based on GI bacteria naturally found in healthy humans, and not associated with disease ✓VOWST product profile includes well tolerated safety without drug-related serious adverse events ✓Wel

  12. Slide 12: Near-term focus on SER-155 and SER-147

    Near-term focus on SER-155 and SER-147 with potential to address expansive therapeutic opportunities Lead Indication & Therapeutic Potential Additional Program Development Stage Objectives Indications Allogeneic HSCT: • Autologous HSCT Reduce incidence of Phase 1b • CAR-T serious bacterial infection

  13. Slide 13: SER-155 is designed to reduce life-threatening complications of allo-HSCT

    SER-155 is designed to reduce life-threatening complications of allo-HSCT • Investigational live oral biotherapeutic cultivated from clonal master cell banks SER-155 • Designed to prevent GI-derived bacterial bloodstream infections (BSIs) and other pathogen-associated complications Allo-HSCT treatme

  14. Slide 14: SER-155 Phase 1b study design in adult allo-HSCT recipients

    SER-155 Phase 1b study evaluated safety, pharmacology, and efficacy in adult allo-HSCT recipients COHORT 1 COHORT 2 Open-label (n=15 enrolled) Placebo-controlled 1:1 (n=45 enrolled) SER-155 SER-155 Placebo results reported May 2023 results announced Sept. 2024 Primary Endpoints: Key Secondary Endpoi

  15. Slide 15: Patient Safety: SER-155 generally well tolerated with no treatment-related SAEs

    Patient Safety: Cohort 2 SER-155 was generally well tolerated with no treatment-related SAEs • All but one subject in the placebo arm experienced at least 1 TEAE • Most common for SER-155 treated subjects (≥50% and with Δ ≥5% greater than placebo): Treatment-emergent diarrhea (86% vs. 74% placebo),

  16. Slide 16: Efficacy: reduction in bacterial BSIs and systemic antibiotic exposure

    Efficacy: SER-155 administration favorable with significant* reduction in both bacterial BSIs and systemic antibiotic exposure; lower febrile neutropenia Significant decrease in bacterial bloodstream infections in SER-155-treated Bloodstream infections subjects vs. placebo Numerically lower incidenc

  17. Slide 17: Bloodstream infections from HSCT Day 0 to Day 100

    Bloodstream infections from HSCT Day 0 to Day 100: Lower incidence in SER-155 treated subjects vs. placebo Bloodstream infections from Day 0 SER-155 Placebo to Day 100 n=20 n=14 (# patients) n (%) n (%) Subjects with confirmed BSI 2 (10.0%) 6 (42.9%) 95% confidence interval (1.2, 31.7) (17.7, 71.1)

  18. Slide 18: Cumulative exposure to systemic antibacterials / antimycotics through Day 100

    Cumulative exposure to systemic antibacterials / antimycotics through HSCT Day 100: Lower incidence in SER-155 treated subjects vs. placebo Cumulative Antibacterial or SER-155 Placebo Antimycotic Exposure n=20 n=14 (HSCT Days) n (%) n (%) Mean (SD) 9.2 (5.44) 21.1 (20.31) Median 9.0 14.0 Min, Max 0,

  19. Slide 19: Cumulative exposure rate to systemic antibacterials / antimycotics

    Cumulative exposure rate to systemic antibacterials / antimycotics through HSCT Day 100: Lower incidence in SER-155 treated subjects vs. placebo Cumulative Antibacterial or SER-155 Placebo Antimycotic Exposure Rate n=20 n=14 (% of days) n (%) n (%) Mean (SD) 0.090 (0.0530) 0.305 (0.2898) Median 0.08

  20. Slide 20: SER-155 Strain Engraftment

    SER-155 Strain Engraftment: Primary objective achieved - drug bacteria strain engraftment was robust and as expected • The majority of SER-155 strains were present at start of HSCT conditioning and durable through chemotherapy exposure • Engraftment decreased but was detectable post- neutrophil reco

  21. Slide 21: Pathogen Domination: prevalence lower versus Historical Control Cohort

    Pathogen Domination: Prevalence in SER-155 Cohort 2 was substantially lower relative to Historical Control Cohort • SER-155 was designed to reduce pathogen domination that has been associated with risk of BSIs 1 and other negative clinical outcomes 2 • In Cohort 2, the ability to detect pathogen dom

  22. Slide 22: Viral prophylaxis provides precedent in medically vulnerable patients

    Viral prophylaxis provides precedent in medically vulnerable patients Prevymis - increasingly used for viral infection prophylaxis (e.g., allo-HSCT and • Overall cost of allo-HSCT is high solid organ transplant populations) (~$400K US year 1 allo-HSCT costs) • Transplant-related complications (e.g.,

  23. Slide 23: SER-155 allo-HSCT commercial opportunity is meaningful

    SER-155 allo-HSCT commercial opportunity is meaningful Serious bacterial infections are frequent, creating a strong medical ✓ rationale for prophylaxis to prevent infections and complications ~40K transplants per year worldwide ✓ Very high overall cost of allo-HSCT and related cost of ✓ complication

  24. Slide 24: Accelerating SER-155 clinical development with positive Ph1b outcomes

    Accelerating SER-155 clinical development with positive Ph1b outcomes Aim to accelerate SER-155 development in allo-HSCT • Potential to follow successful precedent from VOWST development Potential global SER-155 Engage with FDA on advancement of SER-155 allo- development and HSCT program commerciali

  25. Slide 25: Anticipated SER-155 expansion in biologically adjacent populations

    Anticipated SER-155 expansion in biologically adjacent populations Transplants / diagnoses per year Population (US + EU) Autologous HSCT ~30K Blood cancers with high neutropenia rates ~190K (acute myeloid leukemia, multiple myeloma, B cell non-Hodgkin’s lymphomas) Solid organ transplant ~65K (liver,

  26. Slide 26: SER-147 in development to prevent infections in chronic liver disease patients

    SER-147 in development to prevent infections in chronic liver disease patients Substantial unmet need Promising preclinical data SER-147 is an investigational live oral biotherapeutic designed to reduce pathogens 0.5M 2.1M causing gut-seeded SBP and BSIs in liver disease patients Declining E. coli t

  27. Slide 27: End-to-end capabilities and expertise for live biotherapeutics

    End-to-end capabilities & expertise for discovery and development of bacterial live biotherapeutics GI microbiome biomarker & drug Clinical translation target identification & patient subpopulation insights Proven discovery, Lead candidate design, Proprietary know-how on clinical screening, optimiza

  28. Slide 28: Manufacturing platform delivers defined consortia in oral formulation

    Manufacturing platform delivers defined consortia in oral formulation using cost-effective production Strain isolation and characterization pipeline to rapidly identify cGMP- suitable medium components Highly intensive strain bioprocessing leveraging flexible, single-use manufacturing technology for

  29. Slide 29: Maximizing opportunity going forward

    Maximizing opportunity going forward Prevent life-threatening infections in additional populations Additional Treat immune-related diseases (e.g., IBD, GvHD, checkpoint Opportunities colitis, radiation enteritis) Chronic liver disease: Anticipate IND ready in H2 '25 SER-147 Indication expansion (e.g

  30. Slide 30: Summary and path forward

    Summary and path forward Successful VOWST development validates using live biotherapeutics to prevent life-threatening • infections Developing a pipeline of SER-155 Phase 1b placebo-controlled clinical efficacy data further support Seres’ strategy novel live biotherapeutics in • areas of high unmet

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