Pneumonitis in Patients Treated With Anti–Programmed Death-1/Programmed Death Ligand 1 Therapy

PurposePneumonitis is an uncommon but potentially fatal toxicity of anti–programmed death-1 (PD-1)/programmed death ligand 1 (PD-L1) monoclonal antibodies (mAbs). Clinical, radiologic, and pathologic features are poorly described.MethodsPatients who received anti–PD-1/PD-L1 monotherapy or in combination with anti–cytotoxic T-cell lymphocyte-4 mAb were identified at two institutions (Memorial Sloan Kettering Cancer Center: advanced solid cancers, 2009 to 2014, and Melanoma Institute of Australia: melanomas only, 2013 to 2015). Pneumonitis was diagnosed by the treating investigator; cases with confirmed malignant lung infiltration or infection were excluded. Clinical, radiologic, and pathologic features of pneumonitis were collected. Associations among pneumonitis incidence, therapy received, and underlying malignancy were examined with Fisher’s exact test as were associations between pneumonitis features and outcomes.ResultsOf 915 patients who received anti–PD-1/PD-L1 mAbs, pneumonitis developed in 43 (5%;...