Altesa Raises $75M Series B to Advance Rhinovirus Treatment for COPD Patients

Altesa BioSciences announced a $75 million oversubscribed Series B funding round led by Forbion, with participation from Sanofi and existing investors including Medicxi, Pitango, and Atlantic Partners. The proceeds will advance vapendavir, a first-in-class therapeutic for the treatment of rhinovirus, the predominant cause of respiratory exacerbations in millions with COPD and other chronic lung diseases.

The financing will support the CARDINAL study, a Phase 2b multinational randomized placebo-controlled trial that will enroll 900 COPD patients in the US and UK, following them and randomizing when they experience a rhinovirus infection. The trial is expected to commence in Q2 2026. 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.

Vapendavir is an oral capsid inhibitor that is active against more than 97% of rhinovirus strains. Altesa tested the candidate in a phase IIa trial that infected 40 COPD patients with RV-A16, a rhinovirus used to study respiratory infections. After the onset of clinical illness, participants were randomized to receive vapendavir or placebo for seven days. Altesa linked vapendavir to statistically significant improvements on measures of COPD exacerbations and upper respiratory symptoms. The median time to the resolution of infection also favored vapendavir. Vapendavir improved symptoms, reduced duration of illness and viral load, and maintained small airway function in COPD patients experimentally challenged with rhinovirus.

Altesa will present novel data regarding the mechanisms of action and anti-viral coverage of vapendavir and its newly discovered active metabolites at the 39th International Conference on Antiviral Research (ICAR2026), being held April 27–May 1 in Prague, Czech Republic. The data are the first of its kind documenting activity of vapendavir, a capsid inhibitor, against rhinovirus C both preclinically and clinically. Rhinovirus C was previously thought to be insensitive to capsid inhibitors. Both vapendavir and its major metabolite, designated as a New Chemical Entity (ALT-001), have direct activity against all three major rhinovirus species: RV-A, RV-B, and RV-C.

There are no directly targeted therapies for rhinovirus infections, leaving patients reliant on supportive care to manage viruses implicated in 45% of acute exacerbations of COPD. Exacerbations can hospitalize patients, drive declines in lung function and harm quality of life.

Altesa licensed vapendavir from Vaxart in 2021 in a deal worth up to $130 million in milestones. Vaxart acquired vapendavir in 2018 as part of its merger with Aviragen Therapeutics, which reported the failure of the drug candidate to improve outcomes in moderate-to-severe asthmatics with rhinovirus infections in 2017.

In connection with the financing, a partner from Forbion will join the board and a board member will transition to Chair of Altesa's Board of Directors. Altesa disclosed $4 million in seed funding and plans to develop antiviral drugs against common respiratory viruses in 2022. While the immediate focus is on COPD, vapendavir has potential for broader application in other high-risk respiratory populations, including people with asthma.