Disease progression is defined as an absolute decline of 10% or more in predicted FVC within any 12‑month period.
According to the Appraisal Committee, pirfenidone could not be considered a cost-effective use of NHS resources for the population specified in the marketing authorisation (adults with mild to moderate idiopathic pulmonary fibrosis) because the most plausible incremental cost-effectiveness ratio (ICER) for pirfenidone (including the stopping rule), of those presented, lay somewhere between about £25,700 and £28,900 per quality-adjusted life years (QALY) gained compared with best supportive care, and was associated with uncertainties that had the potential to substantially increase the ICER. For people with an FVC between 50% and 80% predicted, the most plausible ICER (including the stopping rule) was also above £20,000 per QALY gained, and associated with uncertainties that had the potential to substantially increase the ICER. However, the committee agreed that it had not seen any clinical evidence to contradict the evidence considered in NICE's previous technology appraisal on pirfenidone so continued to recommend pirfenidone for this population.