Phase 1b ATLAS study results indicate that AP01, a pirfenidone solution for inhalation, may have a favorable safety profile and a potential to improve the lung function of patients with idiopathic pulmonary fibrosis (IPF) after 24 and 48 weeks of treatment, Avalyn Pharma announced.

The article detailing the study results has been published in Thorax, an official journal of the British Thoracic Society.

“Although the ATLAS study’s primary endpoint was safety, secondary measures of efficacy showed a trend towards disease stabilization in participants with IPF who administered high-dose AP01,” Lyn Baranowski, Avalyn’s CEO noted. ”Based on this data, we believe AP01 has the potential to meet or exceed the efficacy of oral pirfenidone without the systemic toxicities that limit its adoption. We are eager to explore this hypothesis in a larger, controlled efficacy trial that we plan to begin later this year.” 

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The open-label ATLAS study recruited 91 patients with IPF intolerant of or ineligible for oral pirfenidone or nintedanib. The participants inhaled 50 mg of pirfenidone daily or 100 mg of pirfenidone twice daily through the eFlow Nebulizer System. The primary goal was to assess the safety, tolerability, and efficacy of the 2 pirfenidone dosing regimens.

Read more about IPF therapies

Of the 91 participants who enrolled, 77 (85%) completed 24 weeks of treatment and proceeded with a higher dose of the medication through week 72. Five participants transitioned to the higher dose before week 48 and 16 more transitioned by week 72.

Of the 54 patients who completed 72 weeks of treatment, 41 (76%) proceeded to the open-label extension study, of which results will be presented at upcoming medical meetings.

At baseline, the mean forced vital capacity (FVC) of the patients receiving the lower dose of inhaled pirfenidone daily was 2.5 L, while the FVC of participants receiving the higher medication dose was 2.6 L.

According to the results, most participants receiving 100 mg of inhaled pirfenidone twice daily had FVC improvement with a mean change of 0.6% at week 24 and −0.4% at week 48. Furthermore, these patients also experienced positive changes in quantitative lung fibrosis scores measured by high-resolution computed tomography.

Read more about IPF complications

Both doses of inhaled pirfenidone were well tolerated with no adverse effects on respiratory rate, spirometry, or oxygenation during or following administration. The adverse events reported after 48 weeks for at least 10% of patients in either dose group included cough, rash, dyspnea, nausea, fatigue, lower respiratory tract infection, and upper respiratory tract infection. 

Aside from a grade 3 parainfluenza virus infection, all other treatment-related adverse events were mild or moderate. The study authors reported on 1 treatment-related liver enzyme increase that was resolved upon dose interruption.

Although oral pirfenidone may successfully reduce the fibrosis rate and improve lung function, it also has a poor tolerability profile and a high incidence of adverse events, including elevated liver enzymes, diarrhea, vomiting, and nausea. 


Avalyn Pharma publishes phase 1b ATLAS results demonstrating stabilization of lung function at 24 and 48 weeks with AP01 and favorable safety profile. News release. Avalyn Pharma; March 23, 2023.