Inhaled Treprostinil Slows decline of Lung Function in IPF: NEJM

A new research published in The New England Journal of Medicine found that among patients with idiopathic pulmonary fibrosis (IPF), inhaled treprostinil reduced the decline in forced vital capacity (FVC) and lowered the number of clinical worsening events when compared to placebo over 52 weeks.

IPF is a chronic condition characterized by irreversible scarring of lung tissue, which leads to worsening breathing difficulties, reduced oxygen exchange, and eventual respiratory failure. Current treatment options remain limited, and many patients continue to experience disease progression despite antifibrotic therapy.

The findings come from the TETON-1 phase 3 trial, along with pooled analyses from both TETON-1 and the previously completed TETON-2 study. This trial investigated whether inhaled treprostinil could provide antifibrotic benefits in IPF based on earlier laboratory and clinical evidence.

This study enrolled 598 patients with IPF, who received either inhaled treprostinil or placebo over 52 weeks. Most participants were already receiving standard antifibrotic medications, reflecting real-world treatment conditions. The primary endpoint was change in forced vital capacity (FVC) which tracks disease progression in IPF.

A substantially smaller decline in lung capacity among patients receiving treprostinil was observed. After one year, the median reduction in FVC was approximately 43 milliliters in the treatment group when compared to 196 milliliters in the placebo group. This was statistically significant and clinically meaningful because slowing FVC decline is associated with delayed disease progression and potentially improved outcomes in IPF.

Clinical worsening including death, respiratory hospitalization, or a significant decline in predicted lung function, occurred in 31.8% of treprostinil-treated patients compared with 44.5% of placebo recipients. This translated into a 33% relative reduction in the risk of clinical worsening over the study period.

The safety profile was generally consistent with prior treprostinil studies. Cough was the most commonly reported side effect, which occurs in more than half of patients receiving the inhaled therapy. Treatment discontinuation rates were somewhat higher in the treprostinil group, largely due to adverse events.

Overall, the findings suggest that inhaled treprostinil may emerge as a valuable addition to current IPF management strategies, particularly along with existing antifibrotic medications. Further long-term studies are imperative to evaluate survival outcomes, durability of benefit from therapy.

Source:

Nathan, S. D., Smith, P., Deng, C., King, C. S., De Salvo, M., Weigt, S. S., Pandya, S., Bandyopadhyay, D., Lasky, J. A., Krishna, R., Hambly, N., Ramaswamy, M., Kebbe, J., Ettinger, N., Gao, J., Rao, Y., Breytenbach, N., Peterson, L., Bell, H., … TETON-1 Trial Investigators. (2026). Phase 3 trials of inhaled treprostinil for idiopathic pulmonary fibrosis. The New England Journal of Medicine, NEJMoa2501488. https://doi.org/10.1056/NEJMoa2501488