Clinical insights on outcomes of corticosteroid administration in immune checkpoint inhibitor-induced pneumonitis by retrospective case series analysis

Abstract

Background For the management of immune checkpoint inhibitor (ICI)-induced pneumonitis (ICI-pneumonitis), discontinuation of ICIs and high dose corticosteroid based on grade are generally recommended. The purpose of this study is to describe management and outcome of ICI-pneumonitis and explore what to consider when managing ICI-pneumonitis with or without corticosteroids in addition to grade. Methods We reviewed data of 706 cancer patients who were treated with ICIs and identified radiographically proven pneumonitis. The diagnosis of ICI-pneumonitis was established after excluding alternative aetiologies either by a bronchoscopy or a thorough examination of clinical features. The evaluation of the management and outcome of pneumonitis were evaluated according to the time of corticosteroid administration. Results ICI-pneumonitis developed in 16 patients (2.3%); nine grade 1, four grade 2 and three grade 3. Initially, 10 patients were spared from corticosteroid administration; fourpatients eventually received corticosteroid after 4 weeks of pneumonitis diagnosis due to clinical, radiographical aggravation and/or clinicians' decision. The other sixpatients never received corticosteroid and improved or remained stable radiographically. When the four and sixpatients were compared, pneumonitis grade was similar, while the latter sixpatients had a later onset from initiation of ICIs (mean 37.48 weeksvs25.45 weeks), more prior lines of chemotherapy (median 2.5 vs 1.0 lines), higher proportion of current/ex-smokers (83.3% vs 50.0%), and fewer other accompanying immune-related adverse events (50% vs 75%). Time to improvement of pneumonitis was similar between the fourpatients who received delayed corticosteroid and fivepatients who received corticosteroid within 4 weeks(3.6 vs 2.5 weeks). Conclusions Our analyses provide clinical insights that stratification of the patients is important in managing ICI-pneumonitis. Along with ICI-pneumonitis grade, more factors associated with the outcome need to be unravelled in the future.