Clinical characteristics, prognostic factors, and feasibility of ICI continuation in immune checkpoint inhibitor-related pneumonitis.

[PURPOSE] Immune checkpoint inhibitor (ICI)-related pneumonitis (ICI-pneumonitis) is a serious complication, whose clinical course and optimal management strategies remain inadequately elucidated. This study clarified whether post-pneumonitis ICI continuation is safe and feasible, identified risk factors for fatal outcomes or successful continuation, and assessed whether findings from patients with lung cancer can be generalized to those with other malignancies.

[METHODS] This retrospective study analyzed data from 1,320 patients who received ICI therapy at Kyushu University Hospital between September 2014 and March 2023. Among these, 300 and 1,020 patients had lung and non-lung cancers, respectively. Clinical characteristics, treatment strategies, and outcomes were compared between the two groups. Predictors of fatal pneumonitis and successful ICI continuation were identified using univariable logistic regression.

[RESULTS] ICI-pneumonitis occurred in 96 (7.3%) patients, with a higher incidence in those with lung cancer (14.0%, [42/300]) than in those with non-lung cancers (5.3%, [54/1020]). Clinical characteristics remained similar across cancer types post-pneumonitis. Diffuse alveolar damage pattern, grade ≥ 3 pneumonitis at diagnosis, and elevated C-reactive protein level were significant predictors of fatal pneumonitis. Among 34 patients who attempted ICI continuation, 20 (58.8%) maintained ICI treatment until disease progression. Successful ICI continuation showed a trend toward association with normal baseline lung parenchyma.

[CONCLUSIONS] The similar characteristics of ICI-pneumonitis across malignancies support the generalizability of management strategies. Approximately one-fifth of patients successfully continued ICI therapy after pneumonitis. Systematic radiological surveillance and appropriate severity-based treatment may help optimize outcomes in patients receiving ICI therapy.