Pirfenidone Helps Blunt Seasonal Peaks in Respiratory Hospitalizations in IPF Patients

When it comes to the general population, it is known that rates of certain respiratory infections as well as mortality associated with them, tend to increase in the colder winter months. Past research has found that those with a rare disease known as idiopathic pulmonary fibrosis (IPF) are also affected by a seasonal variation, with mortality greatest during the wintertime.

Now, new data presented by Brett Ley, MD, from the University of California San Francisco, at the American Thoracic Society (ATS) meeting held this year in San Diego California, suggests that an IPF treatment may be able to help blunt seasonal peaks in respiratory-related hospitalizations. The treatment in question? Genentech’s Esbriet, or pirfenidone.

Esbriet is a prescription medicine that is used to treat those with IPF, a disease that is known to affect about 5 million individuals worldwide and is characterized by a formation of scar tissue within the lungs without a known provocation.

To better assess whether season had any impact on hospitalization and mortality of patients with IPF, investigators pulled data from pivotal studies of pirfenidone. The analysis included over 1,200 patients who were randomized to pirfenidone 2,403 mg/day or placebo in the ASCEND or CAPACITY trials.

For the analysis, investigators looked at how season impacted respiratory-related hospitalization, hospitalization unrelated to respiratory issues, and “a composite outcome of respiratory-related hospitalization or death from any cause” over the course of 12 months by treatment arm.

For each hospitalization and death, researchers looked at the date and location to assign them to a corresponding season; this included Spring, Summer, Fall, Winter, and were defined as starting on the 22nd day of either March, June, September, or December, respectively. For each season, investigators used a Chi-squared test to compare patients with events between treatment groups. To test for trends in patients with events across all seasons, the investigators conducted a repeated-measures analysis for correlated binary data, within each treatment group.

In total, the investigators looked at 623 patients in the pirfenidone arm and 624 in the placebo arms. They found a trend across seasons in the proportion of patients with respiratory-related hospitalizations (p=0.035) and the composite endpoint of respiratory-related hospitalization or death (p=0.026). However, they did not detect a significant trend in those who received pirfenidone across seasons when it came to respiratory-related hospitalizations (p=0.484) or the composite endpoint (p=0.144). Furthermore, the investigators noted that there were a significantly higher proportion of patients in the placebo arm who had been hospitalized for respiratory-related issues (p=0.037) compared with those in the pirfenidone arm.

As for non-respiratory hospitalizations, season did not appear to affect either treatment arms; no significant difference in the proportion of those with non-respiratory hospitalizations between either arm for any season was detected.

“In patients with IPF who received placebo in the ASCEND and CAPACITY studies, more respiratory hospitalizations and respiratory-related hospitalizations or deaths from any cause were observed in Fall and Winter than in Spring and Summer,” the authors wrote. “Pirfenidone appears to blunt seasonal peaks in respiratory hospitalizations.”

They added that as there was not a seasonal trend detected for non-respiratory hospitalizations, this data further supports the specificity of seasonal effect on respiratory-related hospitalizations; however, more research is needed in this area.