Switching antifibrotics in patients with idiopathic pulmonary fibrosis: a multi-center retrospective cohort study

Currently, there are two antifibrotics used to treat idiopathic pulmonary fibrosis (IPF): pirfenidone and nintedanib. Antifibrotics slow disease progression by reducing the annual decline of forced vital capacity (FVC), which possibly improves outcomes in IPF patients. During treatment, patients occasionally switch antifibrotic treatments. However, prognostic implication of changing antifibrotics has not yet been evaluated.

This multi-center retrospective cohort study examined 262 consecutive IPF patients who received antifibrotic therapy. Antifibrotic agents were switched in 37 patients (14.1%). The prognoses were compared between the patient cohort that switched antifibrotics (Switch-IPF) and those without (Non-Switch-IPF) using propensity-score matched analyses.

The median period between the initiation of antifibrotic therapy and the drug switch was 25.8 (12.7-35.3) months. The most common reasons for the switch were disease progression (n = 17) followed by gastrointestinal disorders (n = 12). Of the 37 patients that switched antifibrotics, only eight patients disrupted switched antifibrotics by their adverse reactions. The overall prognosis of the Switch-IPF cohort was significantly better than the Non-Switch-IPF cohort (median periods: 67.2 vs. 27.1 months, p < 0.0001). In propensity-score matched analyses that were adjusted to age, sex, FVC (%), history of acute exacerbation, and usage of long-term oxygen therapy, the Switch-IPF cohort had significantly longer survival times than the Non-Switch-IPF group (median 67.2 vs. 41.3 months, p = 0.0219). The second-line antifibrotic therapy showed similar survival probabilities than those in first-line antifibrotic therapy in multistate model analyses.

Switching antifibrotics is feasible and may improve prognosis in patients with IPF. A further prospective study will be required to confirm clinical implication of switching the antifibrotics.