Patients with idiopathic pulmonary fibrosis (IPF) who received pirfenidone showed reduced progression of disease, and patients with greater disease severity had a more prominent reduction response, according to recent research from the American Thoracic Society meeting in Dallas.

“The effect of reducing disease progression [with] pirfenidone persisted even with continual lower dose of pirfenidone and was more prominent in advanced IPF patients,” Jong Sun Park, MD, PhD, from the Seoul National University Bundang Hospital in Seongnam, Republic of Korea, and colleagues wrote in their abstract. “Adverse events were similar regardless of dose but more prevalent in advanced IPF patients.”

Lung illustration. Source: Getty

Although it has been established that pirfenidone reduces disease progression in IPF patients, the researchers sought to examine the efficacy and rate of adverse events based on dose and disease severity in a practice setting. They performed a multi-center retrospective cohort study of 338 IPF patients from 3 referral centers in Korea between July 2012 and March 2018. Patients received pirfenidone at a standard dose of 1,800 mg or a non-standard dose below 1,200 mg (80% of patients).

The standard pirfenidone dose was administered for a minimum of 6 months, and patients had a mean treatment duration of 16.1 months. The annual rate of forced vital capacity (FVC) decline and diffusing capacity of the lungs for carbon monoxide (DLCO) were used to determine treatment efficacy, and researchers used a linear mixed effects model to analyze the change over time.

Prior to pirfenidone treatment, the researchers found the annual decline in FVC was –5.34% (95% CI, –6.56 to –4.12), which improved to –2.89% (95% CI, –3.64 to –2.14) per year after pirfenidone treatment. While there were significant reductions in FVC and DLCO after treatment with pirfenidone (P < .001), patients who received pirfenidone at a dose < 1,800 mg showed a similar reduced rate of IPF disease progression, researchers said. This effect was also “more prominent” among IPF patients with more severe disease, categorized by a Gender-Age-Physiology (GAP) Index between stage II and stage II.

With regard to adverse events, 36.4% of patients reported anorexia, 28.7% reported a skin rash and 26.3% reported dyspepsia. The researchers noted the rate of adverse events were similar among all pirfenidone dose groups, but IPF patients classified between GAP stage II and stage II had a higher rate of adverse events.