---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-25-122724"
form_type: "8-K"
ticker: "ALT"
cik: "0001326190"
company_name: "Altimmune, Inc."
filed_at: "2025-12-19T23:59:59+00:00"
generated_at: "2026-05-16T12:32:18.420436+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.9
calibrated_materiality_score: 0.9
confidence: "high"
source: SEC EDGAR
---

# Altimmune reports positive 48-week IMPACT data; FDA agrees on Phase 3 path for pemvidutide

## Summary
- Pemvidutide 1.8 mg reduced ELF by -0.58 (p<0.0001) and LSM by -3.97 (p<0.001) vs placebo at 48 weeks.
- Weight loss of 7.5% (1.8 mg, p<0.0001) vs 0.2% placebo; no plateau at 48 weeks; AE discontinuation 1.2% vs 3.5%.
- Proportion achieving both ELF ≥0.5 reduction and LSM ≥30% reduction: 32.4% (1.8 mg) vs 3.2% placebo (p<0.0001).
- End-of-Phase 2 FDA meeting on Dec 11 aligned on Phase 3 design; FDA open to AIM-MASH AI tool; plan to evaluate 2.4 mg dose.
- Altimmune raised ~$54.6M net from ATM sales of 13.5M shares after Sep 30, 2025.

## SEC filing metadata
- accession: 0001104659-25-122724
- form_type: 8-K
- ticker: ALT
- cik: 0001326190
- company_name: Altimmune, Inc.
- filed_at: 2025-12-19T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.9
- calibrated_materiality_score: 0.9
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1326190/000110465925122724/0001104659-25-122724-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1326190/000110465925122724/tm2533869d1_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-25-122724
- JSON: https://secwatch.observer/filing/0001104659-25-122724.json
- Plain text: https://secwatch.observer/filing/0001104659-25-122724.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.