| Study 004 | Study 006 | Pooled data | ||||||||||
| Pirfenidone 2403 mg·day−1 | Placebo | Absolute difference (95% CI) | p-value# | Pirfenidone 2403 mg·day−1 | Placebo | Absolute difference (95% CI) | p-value# | Pirfenidone 2403 mg·day−1 | Placebo | Absolute difference (95% CI) | p-value# | |
| Categorical change in FVC ≥10% | 35 (20) | 60 (35) | 14.4 (7.4–21.3) | 0.001ƒ | 39 (23) | 46 (27) | 3.8 (-2.7–10.2) | 0.440ƒ | 74 (21) | 106 (31) | 9.1 (4.3–13.9) | 0.003ƒ |
| PFS time¶ | 0.64 (0.44–0.95) | 0.023## | 0.84 (0.58–1.22) | 0.355## | 0.74 (0.57–0.96) | 0.025## | ||||||
| Mean change in 6MWT distance m | -60.4 | -76.8 | 16.4 (-10.9–43.7) | 0.171 | -45.1 | -76.9 | 31.8 (3.2–60.4) | 0.0009 | -52.8 | -76.8 | 24.0 (4.3–43.7) | 0.0009 |
| Mean change in DL,CO % pred | -7.9 | -9.9 | 2.0 (-0.4–4.4) | 0.145 | -9.8 | -9.2 | -0.5 (-3.2–2.2) | 0.996 | -8.8 | -9.6 | 0.7 (-1.1–2.5) | 0.301 |
| Mean change in dyspnoea score+ | 12.1 | 15.2 | -3.1 (-8.5–2.3) | 0.509 | 11.9 | 13.9 | -2.0 (-7.6–3.6) | 0.604 | 12.0 | 14.5 | -2.5 (-6.4–1.4) | 0.405 |
| Mean change in worst Sp,O2 during 6MWT % | -1.5 | -2.3 | 0.8 (-0.2–1.8) | 0.087 | -1.9 | -1.3 | -0.5 (-1.7–0.7) | 0.893 | -1.7 | -1.8 | 0.1 (-0.7–0.9) | 0.261 |
| Time to worsening in IPF¶ | 0.84 (0.50–1.42) | 0.515## | 0.73 (0.43–1.24) | 0.248## | 0.78 (0.54–1.14) | 0.201## | ||||||
| Categorical change in HRCT diagnosed fibrosis§ | NA | NA | NA | NA | NA | NA | NA | 0.894 | NA | NA | NA | NA |
Data are presented as n (%), unless otherwise stated. FVC: forced vital capacity; PFS: progression-free survival; 6MWT: 6-min walk test; DL,CO: diffusing capacity of the lung for carbon dioxide; % pred: % predicted; Sp,O2: arterial oxygen saturation measured by pulse oximetry; IPF: idiopathic pulmonary fibrosis; HRCT: high-resolution computed tomography; NA: not applicable. #: rank ANCOVA (pirfenidone versus placebo), unless otherwise stated; ¶: hazard ratio (95% confidence interval) based on the Cox proportional hazard model with geographic region (USA versus non-USA) as a stratum; +: based on the University of California San Diego Shortness of Breath questionnaire, total score ranges from 0 to 120 with larger score indicating greater shortness of breath; §: Cochran–Mantel–Haenszel row mean score test (pirfenidone versus placebo) based on five categories (much better, better, same, worse or much worse), assessed in study 006 only; ƒ: Cochran–Mantel–Haenszel row mean score test (pirfenidone versus placebo) based on five categories (severe decline, ≥20%; moderate decline, <20% but ≥10%; mild decline, <10% but ≥0; mild improvement, >0 but <10%; moderate improvement ≥10%); ##: log-rank test (pirfenidone versus placebo). Reproduced from [38] with permission from the publisher.