Patterns of discontinuation in the long-term RECAP study of pirfenidone (PFD) in patients with idiopathic pulmonary fibrosis (IPF)

Introduction: RECAP (NCT00662038) was a single-arm, open-label safety study of PFD that enrolled 1058 patients who received PFD or placebo in the pivotal Phase 3 ASCEND and CAPACITY studies. Median duration of PFD use was 122.4 (0–349) wks. We examined patterns of premature discontinuation to further characterise these patients. Methods: Discontinuation reasons were summarised by prior treatment group and time to discontinuation. Results: 626 (59.2%) patients discontinued PFD due to: adverse event (AE) other than IPF (n=243; 23.0%), AE related to IPF progression (n=115; 10.9%), death (n=95; 9.0%), lung transplant (n=44; 4.2%) or other reason (e.g. withdrawn consent; n=129; 12.2%). For each category, discontinuation rates were similar in patients regardless of prior treatment group, except for AEs other than IPF, which were more frequent in newly initiated patients (25.3% vs 20.8%). Discontinuation was most frequent in Year 1 for all reasons and generally reduced over time. This trend was most pronounced for AEs other than IPF: 44.0% (n=107) in Year 1 vs 24.7% (n=60) in Year 2 (Figure). Conclusions: In RECAP, the majority of discontinuations due to AEs were unrelated to IPF progression. AEs were most frequent in patients initiating PFD and in the first year of treatment, suggesting that close monitoring of patients during this time is important to reduce the risk of discontinuation.