Patients with idiopathic pulmonary fibrosis may benefit from continued treatment with the anti-fibrotic pirfenidone even if their disease has progressed, new evidence suggests.

The exploratory analysis involved 1247 patients with IPF from the CAPACITY and ASCEND phase III studies who were randomised to treatment with pirfenidone (Esbriet) or placebo.

Results showed that patients with IPF who had a ≥10% absolute decline in FVC during the first six months of treatment with pirfenidone and continued treatment reduced the risk of a second ≥10% decline in FVC or death compared with placebo (5.9% vs 27.9%; relative difference, 78.9%).

One death occurred in the pirfenidone group compared to 14 deaths in the placebo group (relative difference, 85.7%) reported the research team that included Ian Glaspole from the Alfred Hospital and Monash University in Melbourne in Thorax.

According to the research team their analysis revealed two important observations that had clinical implications for the management of patients.

Firstly, the rate of decline in patients was ‘highly variable’ and could not be predicted.

“Analysis of longitudinal FVC data showed a weak inverse correlation between changes in FVC during two consecutive 6-month intervals, highlighting the variability in both the magnitude and direction of change in this prospective, clinical trial population,” they wrote.

Secondly, the findings showed that continued treatment with pirfenidone might reduce the risk of a subsequent ≥10% decline in FVC or death.

This observation was particularly relevant to clinicians given the lack of data on second-line treatment in these patients, they said.

“Until such data are available, our findings provide the first available evidence to suggest that continuing treatment with pirfenidone despite evidence of disease progression confers a meaningful benefit,” they concluded.

The study was sponsored by InterMune Inc. (Brisbane, California, USA).