Interstitial lung disease — either associated with connective-tissue diseases, autoimmune, or metabolic conditions, or of unknown cause as in idiopathic pulmonary fibrosis (IPF) — involves irreversible fibrotic damage of the lungs. The anti-fibrotic drugs nintedanib and pirfenidone slow disease progression but since their approval ten years ago, no therapeutic alternatives have become available for patients with progressive pulmonary fibrosis (PFF), including patients with IPF. The results of the phase III FIBRONEER-IPF and FIBRONEER-ILD clinical trials now highlight the potential of the anti-fibrotic and anti-inflammatory agent nerandomilast to slow progression of IPF and PFF.

Nerandomilast is an orally administered inhibitor of phosphodiesterase 4B. Participants in the 52-week trials received nerandomilast 9 mg or 18 mg twice daily or placebo. Randomization of patients (n = 1177 in the IPF study and n = 1176 in the PFF study) was stratified on the basis of whether they had previously received antifibrotic treatment with nintedanib or pirfenidone.