Effectiveness and safety of pirfenidone for idiopathic pulmonary fibrosis

Objectives To assess the long-term effectiveness of pirfenidone in idiopathic pulmonary fibrosis (IPF) treatment and to establish its adverse effects profile. Methods Retrospective observational study in patients with IPF who initiated treatment with pirfenidone between 2011 and 2016. We collected demographic variables (age, sex); date of first and last treatment; reason for discontinuation; pulmonary function measures (forced vital capacity (FVC), carbon monoxide diffusion capacity (DLCO), and 6 min walk test (6MWT)) at treatment initiation (baseline) and at 1, 2 and 3 year follow-up; adherence to pirfenidone treatment; recorded adverse effects; and mortality. Results Thirty-one patients treated with pirfenidone were included; mean +/- SD age was 69 +/- 8 years, 74% were men, and 59% had a smoking history. Mean baseline values were: FVC 2.43 +/- 0.66 L (61.8 +/- 12.1%); DLCO 46.1 +/- 19.4%; and 6MWT 334 +/- 125 m. Median duration of treatment was 14 +/- 13 months, and treatment was discontinued in 58% of patients. The most frequently observed adverse effects were gastrointestinal disturbances and photosensitivity. Twenty (65%) patients were evaluated at 1 year, when mean FVC was 2.41 +/- 0.86 L (64.7 +/- 20.3%); DLCO 50.8 +/- 26.8%; and 6MWT 341 +/- 139 m. At 2 years' follow-up, 11 patients (36%) who were still taking pirfenidone were evaluated. Mean FVC was 2.34 +/- 0.79 L (66.2 +/- 14.7%); DLCO 50.0 +/- 28.3%; and 6MWT 265 +/- 121 m. At 3 years, five patients were still taking the treatment. Mean FVC was 2.71 +/- 0.84 L (71.0 +/- 24.7%); DLCO 52.6 +/- 26.7%; and 6MWT 286 +/- 139 m. Nineteen per cent of patients were non-adherent to treatment. Conclusions Pirfenidone seems to be effective for long-term control of IPF despite substantial variability in response among individual patients. The most frequent adverse effects were digestive and cutaneous, prompting in some cases a reduction in dose or even discontinuation of the treatment.