Cost-effectiveness of pirfenidone for patients with cancer and grade 2 or grade 3 radiation-induced lung injury: A modeling study

Background: The cost-effective treatment strategy for radiation-induced lung injury (RILI) remains unclear. Our recent phase II randomized clinical trial has proved pirfenidone to be safe and effective for grade 2 or 3 RILI. Here, we aim to assess the cost-effectiveness of pirfenidone plus glucocorticoids versus glucocorticoids alone for the treatment of grade 2 or 3 RILI. Methods and findings: We constructed a Markov model based on the individual-level data from our trial (NCT03902509) to evaluate the cost-effectiveness of pirfenidone plus glucocorticoids. Outcomes were simulated in a 4-week cycle over a 24-week time horizon to model patients who had acute pulmonary exacerbation or RILI progression. Costs and utilities were discounted at 3% annually. Health outcomes were measured using incremental cost-effectiveness ratio (ICER), representing incremental costs per quality-adjusted life year (QALY) gained between the two treatment groups. One-way and probabilistic sensitivity analyses were conducted to evaluate the model uncertainties. The simulated RILI pattern in the Markov model closely matched the pattern in the trial cohort, indicating that the model accurately described the disease process of RILI. Compared with glucocorticoids alone, pirfenidone plus glucocorticoids yielded an additional 0.028 QALYs at an incremental cost of $590, with an ICER of $20,956 per QALY gained. The ICER was considerably below the commonly accepted willingness-to-pay (WTP) threshold of $100,000 per QALY. In one-way sensitivity analyses, the variables with the greatest influence on the ICER included the acute pulmonary exacerbation-free survival and the probability of non-response among patients with grade 2 or 3 RILI in glucocorticoid group. Moreover, the probabilistic sensitivity analysis demonstrated that pirfenidone plus glucocorticoids had a 99.98% probability of being cost-effective at the WTP threshold of $100,000/QALY. Limitations include the phase II trial data with limited sample size and follow-up. An ongoing phase III trial will provide further evidence. Conclusions: For grade 2 or 3 RILI, pirfenidone plus glucocorticoids is cost-effective compared with glucocorticoids alone. This strategy offers a practical and evidence-based option for RILI clinical management. Why was this study done?: What did the researchers do and find?: What do these findings mean?: In this modelling study, Qiu-Yi Pan and colleagues provide a cost-effectiveness analysis of pirfenidone plus glucocorticoids versus glucocorticoids alone for the treatment of Grade 2 and Grade 3 Radiation-Induced Lung Injury in patients with cancer.