Characteristics and clinical outcomes of checkpoint inhibitor-associated pneumonia in cancer patients: a retrospective analysis of 1 084 cases

Abstract

Objective To investigate the incidence, risk factors, treatment outcomes, and other clinical outcomes of checkpoint inhibitor-related pneumonitis (CIP) in cancer patients treated with PD-1/PD-L1 inhibitors. Methods Clinical data of 1 084 cancer patients who received treatment with PD-1/PD-L1 inhibitors from 2019 to 2021 in Department of Oncology of the Second Affiliated Hospital of Army Medical University were collected and then retrospectively analyzed. The patients were divided into a non-CIP group (998 cases) and a CIP group (86 cases), and those from the latter group were further divided into G1~G4 grades, of which G1~G2 grades were classified as low-grade CIP subgroup (69 cases) and G3~G4 grades as high-grade CIP subgroup (17 cases). Chi-square test, binary logistic regression and Kaplan-Meier survival analysis were used to summarize the incidence, risk factors, treatment outcome of CIP and its relationship with immune efficacy and progression-free survival (PFS). Results The incidence of CIP was 7.93% (86/1 084) in the cohort, the rate of high-grade CIP was 1.57% (17/1 084), and the rate of mortality was 0.09% (1/1 084). Binary logistic regression analysis showed that history of chronic obstructive pulmonary disease (COPD, OR=3.018, P=0.036) and history of chest radiotherapy (OR=2.605, P < 0.001) were independent risk factors for CIP. The patients with an age of ≥65 years had an obviously higher incidence of high-grade CIP than those with younger age (P=0.021). There were no statistical differences in objective remission rate (ORR), disease control rate (DCR) and PFS between the non-CIP group and the CIP group. Out of the 86 CIP patients, 50(58.14%) stopped immunotherapy, the other 36 (41.86%) continued or restarted immunotherapy. One (1.16%) patient died of respiratory failure, and the remaining patients were relieved after drug withdrawal, hormone therapy, immunosuppressive therapy, etc. Conclusion The cancer patients with history of COPD or chest radiotherapy have a higher incidence of CIP after PD-1/PD-L1 treatment. Patients with advanced age are prone to high-grade CIP. Most CIP patients can achieve good outcomes after active treatment, and some with low-grade CIP can restart immunotherapy.

Keywords

• immune checkpoint inhibitor
• programmed death receptor-1/programmed death ligand-1 inhibitors
• checkpoint inhibitor-related pneumonitis
• cancer