Vast Therapeutics Completes First Milestone in Phase 1 Clinical Program

Inhaled ALX1 Safely Delivered at All Dose Levels of Single Ascending Dose (SAD) Study

Unlocks Targeted Delivery of Water-Soluble Nitric Oxide in Chronic Respiratory Diseases

MORRISVILLE, N.C., Nov. 18, 2025 /PRNewswire/ -- Vast Therapeutics, a clinical-stage life science company, today announced that it has successfully completed the Single Ascending Dosing (SAD) portion of the Phase 1 program for the company's ALX1 drug candidate which evaluated safety, tolerability and pharmacokinetics in thirty-two healthy adults. 

ALX1 was well tolerated, and dose-escalation occurred to all four of the pre-specified exposure levels. No severe or serious adverse events were observed. "The impressive tolerability in healthy volunteers is the first step in generating valuable safety data for doses of nitric oxide that we believe can lead to meaningful changes for patients in our upcoming Phase 2 program," stated Paul Bruinenberg MD, MBA, Chief Medical Officer at Vast Therapeutics.

ALX1, is a first-in-class small molecule prodrug designed to efficiently deliver localized nitric oxide to targeted areas within the lung. The drug product is nebulized daily as a fine mist using a hand-held, portable inhalation device. The Phase 1 single and multiple ascending dose studies are being conducted in San Antonio, TX under an open Investigational New Drug application with the U.S. Food and Drug Administration. 

"Vast's targeted approach can be transformational," says James Chalmers, MBChB, PhD, Professor and Consultant Respiratory Physician at the School of Medicine, University of Dundee, UK. "The ability to deliver nitric oxide in liquid form has the potential to overcome previous limitations with inhaled gas and thus provides a novel mechanism to address the underlying pathology of bronchiectasis, cystic fibrosis, and other chronic respiratory diseases."

The company has initiated the Multiple Ascending Dosing (MAD) portion of the program and intends to announce complete results from the Phase 1 program in 1Q 2026. The Phase 2 program in patients with bronchiectasis is targeted to begin 1H 2026.

About Bronchiectasis 
Bronchiectasis is a chronic lung disease that affects approximately 400,000 adults in the United States and several million worldwide. People with bronchiectasis have severe and progressive lung disease characterized by irreversibly damaged dilated bronchial airways associated with increased mucous production, reduced mucus clearance, recurrent infection, persistent airway inflammation, and related lung damage. The condition is marked by frequent pulmonary exacerbations requiring antibiotic therapy and/or hospitalizations.

About Vast Therapeutics
Vast is a clinical-stage life science company committed to creating transformative medicines for patients with serious lung diseases. The debilitating cycle of chronic infection and inflammation affects lungs across the entire spectrum of human life, ranging from children with rare orphan diseases like cystic fibrosis (CF) to adults with the highly prevalent chronic obstructive pulmonary disease (COPD). Our drug candidates target the nitric oxide insufficiency in these diseases to provide both meaningful patient benefits as well as address underlying causality.

Contact:
Nathan Stasko
Chief Executive Officer
Vast Therapeutics, Inc.
[email protected]

SOURCE Vast Therapeutics, Inc.