Altimmune (ALT) investor relations material

Study design and endpoints

• IMPACT phase 2b trial enrolled 212 MASH patients with moderate to advanced fibrosis, randomized to placebo, 1.2 mg, or 1.8 mg pemvidutide weekly for 48 weeks without titration.

• Primary endpoints were MASH resolution or fibrosis improvement at 24 weeks; secondary endpoints included non-invasive tests, weight loss, and safety tracked through week 48.

• cT1 MRI-based imaging and non-invasive markers (ELF, LSM) showed dose-dependent improvements, with reductions above thresholds for MASH resolution and fibrosis improvement.

• Over 50% reduction in liver fat content and significant ALT normalization were achieved and maintained at 48 weeks, especially with 1.8 mg.

• Pemvidutide is a balanced 1:1 glucagon/GLP-1 dual receptor agonist targeting liver and metabolic drivers of MASH.

Efficacy and safety results

• Statistically significant improvements in fibrosis markers, liver health, and weight loss (4.5% at 1.2 mg, 7.5% at 1.8 mg) were observed at 48 weeks, with no plateau at the higher dose.

• Both diabetic and non-diabetic patients showed similar efficacy and safety outcomes.

• Safety profile was strong: most adverse events were mild to moderate, with low rates of serious or severe events and no increase in cardiac events.

• Discontinuation rates due to adverse events were lower than placebo, with favorable GI tolerability, especially at 1.2 mg.

• Favorable tolerability profile was maintained at 48 weeks, supporting long-term use.

Regulatory and phase 3 planning

• Productive end-of-phase 2 FDA meeting led to alignment on phase 3 design for MASH patients with moderate to advanced fibrosis and biopsy-driven endpoints.

• FDA is open to incorporating AIM-MASH AI pathology tool to standardize biopsy readings and potentially reduce trial size.

• Phase 3 will evaluate both 1.8 mg and 2.4 mg doses, with simple titration strategies to maintain tolerability.

• Phase 3 sample size expected to be 1,000–1,500 patients, with long-term follow-up for clinical outcomes; trial initiation targeted for 2026.

• FDA granted Fast Track designation for pemvidutide in MASH and alcohol use disorder.