ALT · Altimmune, Inc.

Altimmune, Inc. entered into an underwriting agreement on April 22, 2026, with Leerink Partners LLC and Barclays Capital Inc. as representatives, culminating in the closing of a significant public offering on April 24, 2026. The transaction involved the sale of 64,250,000 shares of common stock (par value $0.0001) at a public offering price of $3.00 per share, or pre-funded warrants at $2.999 per warrant for certain investors, each bundled with a common stock warrant exercisable for one share at $3.00. The pre-funded warrants, exercisable at a nominal $0.001 per share with no expiration, provide flexibility for investors facing ownership restrictions. Aggregate warrants cover up to 75,000,000 shares, reflecting a 1:1 ratio for shares/pre-funded warrants plus additional warrants. These warrants feature a milestone-based termination—earlier of five years from issuance or 45 days post public announcement of successful Phase 3 data for pemvidutide in MASH—aligning investor interests with clinical progress. Beneficial ownership caps at 4.99% or 9.99% (holder-elected), adjustable up to 19.99% with 61-day notice, mitigating dilution risks. Net proceeds of $211.2 million, post discounts and expenses, substantially bolster the balance sheet. Allocation prioritizes advancing pemvidutide's global Phase 3 MASH trial, initiating pre-commercialization for this lead asset in metabolic dysfunction-associated steatohepatitis, and general purposes, extending runway amid biotech funding challenges. The offering utilized effective S-3 registrations, with legal opinion from Goodwin Procter LLP confirming validity. Warrants will not be listed on Nasdaq, traded OTC. This capital raise positions Altimmune to execute on high-value clinical milestones without immediate dilution pressure from warrant exercises.