Slide 1: 48-Week IMPACT Phase 2b Topline Data Presentation
48-Week IMPACT Phase 2b Topline Data Presentation December 2025
Slide 2: Forward Looking Statements
Forward Looking Statements This presentation has been prepared by Altimmune, Inc. ("we," "us," "our," "Altimmune" or the "Company") and includes certain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, including, but not limited to, statements
Slide 3: Pemvidutide: Addressing Both the Cause and Consequence of Metabolic Liver Diseases
Pemvidutide: Addressing Both the Cause and Consequence of Metabolic Liver Diseases Currently available therapies often do not treat the totality of the disease, provide limited effectiveness, or have a poor tolerability profile Pemvidutide: Balanced 1:1 glucagon/GLP-1 dual receptor agonist Glucagon
Slide 4: Early Effect on MASH + Tolerability Observed at 24 Weeks
Early Effect on MASH + Tolerability Observed at 24 Weeks 24 Weeks 1 2 3 Rapid and significant reductions Weight loss with Trending improvement in liver fat and markers of no evidence of plateauing of fibrosis as measured by inflammation, with early MASH at 24 weeks biopsy data resolution 4 5 Results
Slide 5: Topline Results Achieved Key Measures of Success at 48 Weeks
Topline Results Achieved Key Measures of Success at 48 Weeks 48 Weeks 1 2 Further improvements Established clear dose response in NITs including antifibrotic with strong 1.8 mg performance observed on activity in ELF and LSM (Fibroscan) all evaluated parameters, including additional weight loss 3 4
Slide 6: IMPACT Phase 2b MASH Trial Design
IMPACT Phase 2b MASH Trial Design Screening/Randomization Placebo (PBO) weekly Key Eligibility Criteria 1.2 mg weekly MASH (F2/F3) LFC(1) ≥ 8% BMI ≥ 27.0 kg/m2 1.8 mg weekly HbA1c ≤ 9.5% N = 212 subjects randomized 2:1:2 No dose titration Key Endpoints Primary Week 24 Week 48 MASH resolution
Slide 7: Substantial Improvements in Non-invasive Tests of Fibrosis at 48 Weeks
Substantial Improvements in Non-invasive Tests of Markers of Fibrosis at 48 Weeks, Dose Response Favors 1.8 mg ≥0.5 ELF Reduction + 30% LSM Enhanced Liver Fibrosis (ELF) Liver Stiffness Measurement (LSM) Reduction Threshold 0.50 0.0 100 -0.5 LS Mean Change from Baseline (kPa ± SE) 90 0.16 LS Mean Ch
Slide 8: Improvements in Primary Non-invasive Markers of Fibrosis from 24 to 48 Weeks
Improvements in Primary Non-invasive Markers of Fibrosis from 24 to 48 Weeks with 1.8 mg, Supporting Phase 3 Development Enhanced Liver Fibrosis (ELF) Liver Stiffness Measurement (LSM) Placebo-Adjusted Placebo-Adjusted 0 0 LS Mean Change from Baseline (kPa ± 95% CI) -1 LS Mean Change from Baseline (
Slide 9: Enhanced Liver Fibrosis (ELF) Response
Enhanced Liver Fibrosis (ELF) Response Placebo adjusted based upon published data ELF was evaluated as a secondary endpoint in the trials shown. No head-to-head studies of pemvidutide to other Pemvidutide Resmetirom Tirzepatide Semaglutide Efruxifermin (GLP-1/GCG) (THR-β) (GLP-1/GIP) (GLP-1) (FGF21)
Slide 10: LSM (Fibroscan) Response
LSM (Fibroscan) Response Placebo adjusted based upon published data LSM was evaluated as a secondary endpoint in the trials shown. Pemvidutide Resmetirom Tirzepatide Semaglutide Efruxifermin No head-to-head studies of pemvidutide to other (GLP-1/GCG) (THR-β) (GLP-1/GIP) (GLP-1) (FGF21) MASH products
Slide 11: 1.8 mg Dose Maintained >50% Reduction in Liver Fat Over 48 Weeks
1.8 mg Dose Maintained >50% Reduction in Liver Fat Over 48 Weeks Liver Fat Content Reduction 80 Similar levels of liver fat LS Mean Relative Change from Baseline (% ± SE) 70 reduction were observed as **** 54.7 early as 24-weeks 60 **** 45.2% 50 Liver fat content is a key 40 driver of MASH and fibro
Slide 12: Significant Reductions in Alanine Aminotransferase (ALT)
Significant Reductions in Alanine Aminotransferase (ALT) Alanine Aminotransferase (ALT) ≤30 IU/L ALT Threshold 0 100 -5 ALT is a measure of hepatic 90 inflammation and disease ** LS Mean Change from Baseline (IU/L ± SE) -10 *** 80 73.7% 72.0% -15 -10.3 -17 >17 IU/L reduction is 70 Proportion of Pati
Slide 13: Significant Reductions in Corrected T1 (cT1)
Significant Reductions in Corrected T1 (cT1) Reduction of ≥80 ms is associated with an improvement in histology in MASH† cT1 cT1 is a non-invasive 0 marker of hepatic LS Mean Change from Baseline (ms ± SE) inflammation -21 -50 80 ms reduction in cT1 is -80 ms associated with 2-point -100 reduction i
Slide 14: Significant and Continuing Weight Loss for 1.8 mg at 48 Weeks
Significant and Continuing Weight Loss for 1.8 mg at 48 Weeks Weight Loss Weight Loss 0 1 -1 -0.2% Weight loss has been 0 shown to be associated LS Mean Relative Change from Baseline (% ± SE) LS Mean Relative Change from Baseline (% ± SE) -2 -1 with MASH -3 -2 improvement† -4 -3 Weight loss of 7.5%
Slide 15: Safety Profile Maintained at 48 Weeks
Safety Profile Maintained at 48 Weeks Placebo 1.2 mg 1.8 mg (N=86) (N=41) (N=85) Serious AEs 5 (5.8%) 1 (2.4%) 8 (9.4%) Serious AEs related to study med 0 (0.0%) 0 (0.0%) 0 (0.0%) Severe AEs 2 (2.3%) 1 (2.4%) 8 (9.4%) Severe AEs related to study med 0 (0.0%) 0 (0.0%) 0 (0.0%) AEs of Special Interest
Slide 16: Favorable Tolerability at 48 Weeks
Favorable Tolerability at 48 Weeks Placebo 1.2 mg 1.8 mg Adverse Events (N=86) (N=41) (N=85) Nausea 15 (17.4%) 9 (22.0%) 35 (41.2%) Vomiting 2 (2.3%) 3 (7.3%) 10 (11.8%) Diarrhea 7 (8.1%) 5 (12.2%) 19 (22.4%) Constipation 10 (11.6%) 5 (12.2%) 15 (17.6%) AEs leading to treatment discontinuation 3 (3.
Slide 17: End-of-Phase 2 Meeting with FDA Key Takeaways + Implications for Phase 3
End-of-Phase 2 Meeting with FDA Key Takeaways + Implications for Phase 3 Productive meeting held with final minutes expected in January Aligned with FDA on pathway to move forward to registrational Phase 3 trial in moderate to advanced fibrosis with biopsy driven endpoints Agency is open to incorpor
Slide 18: Strong Clinical Execution and Future Catalysts
Strong Clinical Execution and Future Catalysts 2025 2026 2027 • MASH: IMPACT Phase 2b 24- and • MASH: Phase 3 trial initiation • MASH: Phase 3 trial 48-Week data execution ongoing • AUD: RECLAIM topline data • MASH: End-of-Phase 2 meeting • AUD: Phase 3 opportunity • ALD: RESTORE enrollment • MASH:
Slide 19: Summary
Summary IMPACT Phase 2b 48-week data achieved key measures of success Data enhance confidence for pemvidutide, with competitive profile supported by 48-weeks data Aligned with FDA on path to Phase 3 in MASH* Series of upcoming catalysts 2026-2028 Strengthened executive team with the right expertise
Slide 20: Thank you
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