Altesa BioSciences Presents Positive Phase 2 Challenge Study Results for Vapendavir at American Thoracic Society International Conference 2026

Randomized, placebo-controlled challenge study demonstrated reduced viral load, reduced inflammation, maintained lung function and improved patient-reported outcomes in COPD patients treated with vapendavir following rhinovirus infection

Phase 2B CARDINAL study, which recently enrolled its first patient, aims to demonstrate that treatment of rhinovirus infections with vapendavir may improve upper and lower airway symptoms, reduce illness duration, and better maintain small airway lung function compared to placebo

ORLANDO, Fla., May 19, 2026 /PRNewswire/ -- Altesa BioSciences, a clinical-stage pharmaceutical company dedicated to improving the lives of people with chronic lung diseases including COPD and asthma, demonstrated positive results from its randomized, placebo-controlled Phase 2 rhinovirus challenge trial evaluating oral vapendavir in patients with GOLD Stage 2 chronic obstructive pulmonary disease (COPD) infected with rhinovirus.

In an oral presentation at the American Thoracic Society International Conference (ATS) 2026, Professor Sebastian Johnston shared detailed results from the study, which met its objectives, demonstrating clinical benefit and antiviral activity when treatment with vapendavir was initiated after the onset of symptoms caused by rhinovirus— a treatment regimen consistent with real-world clinical use. Altesa recently announced that the first patient enrolled in the Phase 2b CARDINAL multinational clinical trial evaluating vapendavir in patients with COPD impacted by rhinovirus.

Rhinovirus infection is the leading cause of exacerbations in COPD, the primary driver of associated morbidity and mortality. There are currently no approved antiviral treatments or vaccines for rhinovirus, leaving a significant unmet need for the millions of patients living with chronic lung disease worldwide. Vapendavir has the potential to shift the treatment paradigm from reactive symptom management to preemptive targeting of rhinovirus before the inflammatory cascade that causes significant respiratory distress is triggered.

"This first of its kind study offers a novel treatment strategy for COPD exacerbations," said Professor Sebastian Johnston, MBBS, PhD, Professor of Respiratory Medicine and Allergy at the National Heart and Lung Institute, Imperial College London, and Chairman and Chief Medical Officer of VirTus Respiratory Research Ltd and the Principal Investigator for the challenge study and global Principal Investigator for Altesa's ongoing Phase 2b CARDINAL study. "This rhinovirus challenge model in COPD was developed precisely for vapendavir, early positive clinical testing signals that justify substantial investment and additional clinical exploration in the Phase 2b CARDINAL study," added Professor Johnston.

Key Challenge Study Phase 2 Results

In the challenge study, vapendavir-treated patients showed:

• Reduced viral load, consistent with previous clinical trials in patients with asthma
• Reduced inflammation reduced several clinically relevant chemokines measured
• Improved median time to symptom resolution, a recommended pivotal trial outcome measure by FDA Division of Antivirals, was 5 days with vapendavir and 8.5 days with placebo– as measured by E-RS
• Improved patient-reported outcomes, including a decrease in the number of subjects with a clinically meaningful worsening in St. George's Respiratory Questionnaire (SGRQ)
• Maintained small airway function as measured by oscillometry
• No safety or tolerability issues identified

The study was carried out at VirTus and Imperial College Healthcare NHS Trust using the only COPD rhinovirus challenge model in operation globally – a model designed to reproduce the upper and lower airway symptoms characteristic of community-acquired illness in COPD patients. Notably, the RV-16 strain used in the challenge was less sensitive to vapendavir than approximately 85% of naturally circulating strains, suggesting the observed clinical benefit should not overrepresent vapendavir's activity against typical real-world infections.

Safety and tolerability of vapendavir have been established in approximately 700 healthy volunteers and patients with asthma or COPD across the development program to date.

Altesa Advancing the Development of Vapendavir in Phase 2b CARDINAL Study

Building on these positive results, Altesa recently initiated its Phase 2b CARDINAL study that will run through Q4 2027. The multi-center, randomized, double-blind, placebo-controlled study will evaluate the safety and efficacy of two doses of oral vapendavir compared with placebo in participants with COPD and confirmed rhinovirus infection. The trial will enroll 900 participants with GOLD Stage 2-4 COPD across 49 sites in the United States and United Kingdom and is event-driven to achieve 180 RV-positive participants randomized to a 7-day, once-daily treatment regimen.

The primary outcome measure is the area under the curve for mean change from baseline of the EXACT-Respiratory Symptoms (E-RS) score, a standardized, daily respiratory symptom diary for COPD. Principal secondary endpoints include time to resolution of upper and lower airway symptoms, need for medical interventions (steroids, beta agonists, antibiotics, hospitalizations, and deaths), quality of life as measured by the SGRQ, pulmonary function, and a comprehensive virology analysis.

"For too long, rhinovirus exacerbations in COPD have been accepted as inevitable – managed after the fact, with no preemptive treatment to interrupt the cascade before it begins," said Dr. Katharine Knobil, Chief Medical Officer of Altesa and former CMO of GSK. "The data shared today at ATS combined with enrollment of the first patient in the CARDINAL trial demonstrate both the potential and the progress we are making with vapendavir to change that. We are energized by these results and committed to moving quickly to deliver a meaningful new option for patients who desperately need it."

About Vapendavir
Vapendavir, taken orally in pill form, is a broad-spectrum, antiviral, investigational drug – preventing the virus from both entering human cells as well as reproducing. It exhibits potent clinical activity across all three types of rhinoviruses, including RV-C, and other respiratory enteroviruses. While the immediate focus is on evaluating vapendavir as a treatment for patients with COPD, vapendavir has potential for broader application in other high-risk respiratory populations, including people with asthma and other chronic lung diseases.

About the CARDINAL Study
The CARDINAL clinical trial is a Phase 2b, multinational, randomized, placebo-controlled study in COPD patients experiencing rhinovirus infections that will enroll 900 people with COPD in the US and UK. The trial was designed to reflect real-world care models, proactively identifying and supporting those at greatest risk. Participants will be closely monitored over time and, upon development of rhinovirus infection, will be randomized to receive one of two doses of vapendavir or placebo. The trial's primary objective is to assess improvement in respiratory symptoms using established patient-reported outcomes, with additional endpoints evaluating time to symptom resolution, quality of life, healthcare resource utilization, and lung function. To learn more, visit www.COPDCardinalStudy.com/join/.

About Altesa BioSciences, Inc.
Altesa BioSciences is a clinical-stage pharmaceutical company led by global experts in respiratory medicine and infectious diseases. Altesa is dedicated to improving the lives of people with chronic lung diseases like COPD and asthma, by treating the principal cause of exacerbations and pathological inflammation–viral respiratory infections. www.altesa.com

About VirTus Respiratory Research Ltd.

VirTus Respiratory Research Ltd is a CRO co-led by Professor Sebastian Johnston and Dr. Michael Edwards, both of Imperial College London, United Kingdom. VirTus is dedicated to accelerating the development of novel therapies for the treatment and prevention of respiratory virus infections, which are the leading cause of acute attacks (exacerbations) in chronic respiratory diseases such as asthma, COPD and bronchiectasis.

Media Contact: Peg Rusconi
Email: [email protected]

SOURCE Altesa Biosciences Inc.