Introduction Pirfenidone has NICE approval and is recommended for patients with IPF if the FVC is 50–80%. We hypothesised that this would disadvantage a significant cohort of IPF patients who have moderate reduction in transfer factor despite preserved FVC.
Methods We present longitudinal data capturing 38 IPF patients who had FVC greater than 80% and not eligible for pirfenidone treatment.
Results Since NICE approval in July 2013, 43 patients were eligible for pirfenidone as per the NICE criteria and 38 (47%) patients were outside the NICE criteria. Of those outside the NICE criteria, the average FVC was 98% (81–145) and average DLCO was 58% (21–88). Sixteen (42%) patients had a DLCO <55%, nine (24%) had DLCO of 56–70% and nine (24%) with DLCO above 70%. Only nine (24%) had CT evidence of emphysema. We had one or more serial lung function results for 17 (49%) patients. A total of 9/38 (24%) patients demonstrated an absolute decline in FVC of over 10% and one patient had an absolute DLCO decline of over 15%. Only one of these patients became eligible for pirfenidone treatment.
This retrospective data demonstrates that the sole use of FVC in the NICE criteria for treating IPF disadvantages patients who demonstrate a significant reduction in transfer factor despite FVC greater than 80%. In this study this reduced transfer factor and preserved FVC can only be attributed to the presence of coexisting emphysema in 9/38 (24%) of patients. Ten (26%) IPF patients not treated with pirfenidone because they did not meet the NICE criteria demonstrate a clinically significant decline in their lung function. Despite this the majority are still not eligible for treatment with pirfenidone.
We would therefore advocate following our European partner countries and using both FVC and DLCO as per the CAPACITY criteria when assessing patient suitability for pirfenidone treatment for IPF, as the use of FVC alone with an upper limit of 80% excludes a substantial cohort of IPF patients who have preserved FVC, moderately reduced DLCO with or without the presence of coexisting emphysema and over time a quarter of these patients demonstrate lung function decline.
CAPACITY Study Group. Pirfenidone in patients with idiopathic pulmonary fibrosis (CAPACITY): two randomised trials. Lancet 2011;377:1760–69