Slide 1: Phase 2 TORREY Study Topline Results
Phase 2 TORREY Study Topline Results 1 December 6, 2022 Exhibit 99.1
Slide 2: Forward Looking Statements
Forward Looking Statements This presentation contains forward-looking statements. All statements other than statements of historical facts contained in this presentation, including statements regarding the potential of seralutinib to serve patients with pulmonary arterial hypertension (PAH), the pot
Slide 3: Presenters for Today's Call
Presenters for Today’s Call 3 Gossamer Bio Faheem Hasnain Co-Founder, Chairman, & Chief Executive Officer Richard Aranda, MD Chief Medical Officer Robert Roscigno, PhD VP, Clinical Development Larry Zisman, MD Sr Dir, Clinical Development Ed Parsley, DO Consultant Pulmonologist Matt Cravets SVP, Bio
Slide 4: TORREY Study Topline Results Highlights
• Met primary endpoint of statistically significant reduction in PVR in a heavily treated, prevalent study population • Functional outcome, six-minute walk test, favored seralutinib, though study was neither powered nor designed for this endpoint • Statistically significant reduction in NT-proBNP, c
Slide 5: TORREY Study Topline Results Highlights, Cont.
• Consistent benefit across pre-specified sub-groups in favor of seralutinib with enhanced effects in patients with more severe disease at baseline§ • Consistently favorable results for hemodynamic and ECHO endpoints Overall Study Population Functional Class III REVEAL 2.0 Risk Score ≥ 6 PVR 6MWD PV
Slide 6: Disease Overview and Available Treatments
Disease Overview and Available Treatments 6
Slide 7: PAH is a Rare and Progressive Disease
PAH is a Rare and Progressive Disease • PAH is a rare, progressive disease1,2 with an estimated worldwide prevalence of 5-25 cases per million per year3 • PAH has no known cure, is associated with poor survival, and has a debilitating impact on the health-related quality of life of patients and care
Slide 8: Functional Class Correlates With Risk Status & Predicts Survival
Newly diagnosed patients 88.0 72.2 75.6 71.7 57.0 60.0 27.2 43.8 Previously diagnosed patients 5 Year Survival* (%)1 FC I FC II FC III FC IV FC I FC II FC III FC IV Functional Class Correlates With Risk Status & Predicts Survival • Analysis of REVEAL Registry shows that 5-year survival remains poor
Slide 9: The Clinical Goal of PAH Therapy is to Achieve Low Risk Status
The Clinical Goal of PAH Therapy is to Achieve Low Risk Status1 • Low risk status usually associated with1 • Good exercise capacity • Good quality of life • Good right ventricular function • Low mortality risk • Patients categorized as low risk1 • Have est. 1-year mortality <5% • Present with non-pr
Slide 10: Unmet need for therapies that target underlying causes of disease
Unmet need for therapies that target underlying causes of disease What Do Currently Available Therapies Do? ERA: endothelin receptor agonist; ET: endothelin; PDE-5i: phosphodiesterase-5 inhibitor; PGI2: sGC stim: soluble guanylate cyclase stimulators. Source: Adapted from Humbert, et al., N Engl J M
Slide 11: Study Design and Baseline Characteristics
Study Design and Baseline Characteristics 11
Slide 12: Study Design
Study Design 12 Screening Double-Blind, Placebo-Controlled Period Follow-up After completing the Week 24 visit, subjects have the option to roll into an open-label extension study Week Visit 4 6 6 12 7 18 8 24 1 -5 to -1 2 (Day 1) 3 2 5 8 S c re e n in g V is it R a n d o m iz a ti o n a Follow-up 2
Slide 13: Patient Disposition
Patient Disposition 13 Placebo N=42 86 patients randomized and dosed Seralutinib N=44 Completed Treatment 41 (97.6%) Completed Treatment 37 (84.1%) Completed Study 42 (100%) Completed Study 38 (86.4%) Discontinued Treatment 7 (15.9%) Adverse Event 6 (13.6%) Protocol Deviation 1 (2.3%) Discontinued T
Slide 14: Baseline Demographics (ITT Population)
Baseline Demographics (ITT Population) 14 Characteristic Placebo (N=42) Seralutinib (N=44) Total (N=86) Age (years) – mean (SD) 49.5 (11.81) 48.3 (12.70) 48.8 (12.22) Sex – n (%) Female 38 (90.5) 40 (90.9) 78 (90.7) Male 4 (9.5) 4 (9.1) 8 (9.3) Race – n (%) White 37 (88.1) 37 (84.1) 74 (86.0) Black
Slide 15: Baseline Background PAH Medication Use (ITT Population)
Baseline Background PAH Medication Use (ITT Population) 15 Characteristic Placebo (N=42) Seralutinib (N=44) Total (N=86) Number of background therapies – n (%) 1 2 (4.8) 1 (2.3) 3 (3.5) 2 16 (38.1) 18 (40.9) 34 (39.5) 3 24 (57.1) 25 (56.8) 49 (57.0) Prostacyclin/Prostacycin Receptor Agonist use – n
Slide 16: Baseline Disease Characteristics (ITT Population)
Baseline Disease Characteristics (ITT Population) 16 Characteristic Placebo (N=42) Seralutinib (N=44) Total (N=86) Age at PAH diagnosis (years) – mean (SD) 41.2 (11.65) 40.7 (15.84) 40.9 (13.87) Years since PAH diagnosis – mean (SD) 8.78 (7.218) 8.07 (7.074) 8.41 (7.111) PAH classification – n (%) I
Slide 17: Baseline Demographics and Disease Characteristics by Baseline WHO FC
Baseline Demographics and Disease Characteristics by Baseline WHO FC (ITT Population) 17 Baseline WHO FC Class II Baseline WHO FC Class III Characteristic Placebo (N=20) Seralutinib (N=30) Total (N=50) Placebo (N=22) Seralutinib (N=14) Total (N=36) Age (years) – mean (SD) 47.6 (11.69) 47.7 (13.42) 4
Slide 18: Primary Endpoint: Change From Baseline in PVR
Primary Endpoint: Change From Baseline in PVR 18
Slide 19: Primary Endpoint: Seralutinib Significantly Reduced PVR at Week 24
Primary Endpoint: Seralutinib Significantly Reduced PVR at Week 24 (ITT Population) 19 Abbreviations: ANCOVA, analysis of covariance; LS, least squares; LSMD, least squares mean difference; ITT, intent-to-treat; PVR, pulmonary vascular resistance. Note: Based on an ANCOVA model with multiple imputat
Slide 20: Seralutinib Consistently Reduced PVR Across All Pre-Specified Sub-Groups
Seralutinib Consistently Reduced PVR Across All Pre-Specified Sub-Groups (ITT Population) 20 Abbreviations: ANCOVA, analysis of covariance; FC, functional class; PVR, pulmonary vascular resistance; WHO, World Health Organization; LSMD, least squares mean difference. a Based on an ANCOVA model with m
Slide 21: Seralutinib's Effect on PVR More Pronounced in More Severe Disease
Seralutinib’s Effect on PVR was More Pronounced in Patients with More Severe Disease at Baseline (ITT Population) 21 WHO Functional Class Change in PVR, by Functional Class REVEAL 2.0 Risk Score Change in PVR, by Risk Score Abbreviations: ANCOVA, analysis of covariance; LS, least squares; LSMD, leas
Slide 22: Observed Reduction in PVR Mainly Driven by Reduction in mPAP
Observed Reduction in PVR Mainly Driven by Reduction in mPAP 22 Abbreviations: ANCOVA, analysis of covariance; CO, cardiac output; LS, least squares; LSMD, least squares mean difference; mPAP, mean pulmonary arterial pressure; RHC, right heart catheterization; PVR, pulmonary vascular resistance. Not
Slide 23: Secondary Endpoint: Change From Baseline in 6MWD
Secondary Endpoint: Change From Baseline in 6MWD 23
Slide 24: Secondary Endpoint: Change in 6MWD from Baseline to Each Visit
Secondary Endpoint: Change in 6MWD from Baseline to Each Visit (ITT Population) 24 Abbreviations: 6MWD, six-minute walk distance; FC, functional class; MMRM, mixed-effects model with repeated measures; WHO, World Health Organization. Note: Based on a MMRM model. Source: Data on file.
Slide 25: Change in 6MWD to Each Visit for Baseline FC III Patients
Secondary Endpoint: Change in 6MWD from Baseline to Each Visit for Baseline FC III Patients (ITT Population) 25 Abbreviations: 6MWD, six-minute walk distance; FC, functional class; MMRM, mixed-effects model with repeated measures; WHO, World Health Organization. Note: Based on a MMRM model. Source:
Slide 26: Change in 6MWD by Functional Class and REVEAL 2.0 Risk Score
Change in 6MWD by Functional Class and REVEAL 2.0 Risk Score (ITT Population) 26 Abbreviations: 6MWD, six-minute walk distance; FC, functional class; LS, least squares; LSMD, least squares mean difference; MMRM, mixed-effects model with repeated measures; WHO, World Health Organization. Note: Based
Slide 27: Exploratory Endpoints & REVEAL 2.0 Risk Score Change
Exploratory Endpoints & REVEAL 2.0 Risk Score Change 27
Slide 28: Seralutinib Led to Statistically Significant Reduction in NT-proBNP
Seralutinib Treatment Led to Statistically Significant Reduction in NT-proBNP (ITT Population) 28 Abbreviations: FC, functional class; LS, least squares; LSMD, least squares mean difference; MMRM, mixed-effects model with repeated measures; NT-proBNP, N-terminal pro B-type natriuretic peptide. Note:
Slide 29: Centrally-Read RHC and ECHO Results at Week 24 Consistently Favored Seralutinib
Endpoint LS Mean Difference (95% CI) Statistically Significant Result Favoring Seralutinib (p ≤ 0.05) Point Estimate Favoring Seralutinib p-value Right Atrium Area (cm2) -1.99 (-3.783, -0.206) 0.0293* RV Free Wall Strain (%) -2.64 (-5.172, -0.098) 0.0420* PA Compliance (mL/mmHg) 0.22 (0.009, 0.423)
Slide 30: Majority of Seralutinib Patients Improved in REVEAL 2.0 Risk Score
The Majority of Patients Receiving Seralutinib Demonstrated an Improvement in REVEAL 2.0 Risk Score at Week 24 30 Post hoc analysis. Odds ratio, 95% CI, and p-value from a stratified Cochran-Mantel-Haenszel chi-square test of improvement (yes vs. no). 1) A 1-point improvement in REVEAL 2.0 Risk Scor
Slide 31: Safety and Tolerability
Safety and Tolerability 31
Slide 32: Top AEs From Imatinib IMPRES Study Not Observed at High Incidence in TORREY
Top AEs From Imatinib IMPRES Study Not Observed at High Incidence in TORREY 32 Abbreviations: AE: adverse event; MedDRA, Medical Dictionary for Regulatory Activities; PT, preferred term. Note: AEs in IMPRES with an incidence ≥ 10% in Imatinib and ≥5% higher in Imatinib than Placebo are summarized fo
Slide 33: Incidence of TEAEs by Preferred Term: ≥ 5% in Seralutinib
Incidence of TEAEs by Preferred Term: ≥ 5% in Seralutinib (Safety Population) 33 Preferred Terma Placebo (N=42) Seralutinib (N=44) Number of subjects with a TEAE 36 (85.7) 41 (93.2) Cough 16 (38.1) 19 (43.2) COVID-19 7 (16.7) 6 (13.6) Diarrhea 3 (7.1) 6 (13.6) Headache 8 (19.0) 6 (13.6) Dizziness 2
Slide 34: Incidence of Adverse Events Leading to Treatment Discontinuation
Incidence of Adverse Events Leading to Treatment Discontinuation (Safety Population) 34 Preferred Terma Placebo (N=42) Seralutinib (N=44) Number of subjects with a TEAE leading to treatment discontinuation 1 (2.4) 6 (13.6) Abdominal pain lower 0 1 (2.3) Cough 0 1 (2.3) Dry mouth 0 1 (2.3) Haemoptysi
Slide 35: Summary of TORREY Topline Results
Summary of TORREY Topline Results 35
Slide 36: Summary of Topline Results
Summary of Topline Results ✓ Primary endpoint met with concordant statistically significant and directional improvements from baseline across multiple endpoints, including hemodynamics, NT-proBNP, and right heart structure and function ✓ Drug characteristics, limited systemic PK, and route of admini
Slide 37: Acknowledgements
Acknowledgements We thank all patients, their families, and all the TORREY study investigators who participated in the trial 37
Slide 38: Next Steps
Next Steps ❑ 1H:23 – Complete End of Phase 2 Regulatory Interactions ❑ 2H:23 – Commence Global Registrational Phase 3 Program in PAH ❑ 2H:23-1H:24 – Commence Development Program in WHO Group 3 PH 38
Slide 39: Participants for Q&A Session
Participants for Q&A Session 39 Gossamer Bio Faheem Hasnain Co-Founder, Chairman, & Chief Executive Officer Richard Aranda, MD Chief Medical Officer Robert Roscigno, PhD VP, Clinical Development Larry Zisman, MD FACC Sr Dir, Clinical Development Ed Parsley, DO Consultant Pulmonologist Matt Cravets S