Immune checkpoint inhibitor (ICI)-related pneumonitis among patients with lung cancer admitted to an Oncology Hospitalist Service: Treatment patterns and hospitalization outcomes.
Authors: Sahar Hadeel Neamat , Aldrich Jeffrey , Peterson Christine B. , Brito-Dellan Norman , Lu Maggie , Shoukier Mahran , Dickson Kodwo , Koom-Dadzie Kwame , Kheder Ed , Franco-Vega Maria , Mohammed Alyssa , Muthu Mayoora , Simbaqueba Cesar , Sibille Michelle , Manzano Joanna-Grace Mayo 
Published: June 2021

e21054

Background: Immune checkpoint inhibitors (ICI) have gained success in the treatment of multiple malignancies including lung cancer. However, immune-related adverse events (irAE) are common with pneumonitis being one of the most fatal having a 10% mortality rate. As such, early identification and treatment of irAEs are important. We describe the treatment patterns and hospitalization outcomes of patients with lung cancer with grade ≥3 ICI-related pneumonitis (ICI-P) admitted to an oncology hospitalist service at a comprehensive cancer center. Methods: We performed a retrospective review of patients with lung cancer admitted to our oncology hospitalist service with a suspicion of ICI-P between January 1, 2019 and November 30, 2019. ICI-P was confirmed if the patient received irAE-specific management, or if there was multidisciplinary consensus among treating providers. Descriptive statistics were utilized. Here we present the demographic and clinical characteristics of the study population as well as hospitalization outcomes. Results: We identified 49 patients with lung cancer who received at least one dose of ICI before being admitted with a suspicion of ICI-P. The mean age was 67y, with 63% being male and 86% having a diagnosis of non-small cell lung cancer. The most common ICI received by patients was pembrolizumab (67%). 84% were on active ICI treatment at the time of hospitalization and the median time from the 1st ICI dose to hospitalization was 3.5 months. Pulmonology was consulted in 88% of patients. Only 63% (n=31) of those admitted with a suspicion of ICI-P were confirmed to have ICI-P. The mean time to first ICI-P directed treatment was 2.2 days from admission with all 31 patients receiving corticosteroids. 23% required infliximab and 10% required IVIG. Patients with confirmed ICI-P had a median length of stay of 8 days, with 19% requiring ICU stay. The ICI-P inpatient mortality rate was 32%. Of those discharged alive (n=21), 90% were discharged on oral corticosteroids. GI and PJP prophylaxis were prescribed for 95% and 81% of the discharged patients, respectively. The 30-day readmission rate for this subgroup was 29%. 86% were seen by their oncologist within a median time of 8 days from discharge. Conclusions: Studies have shown that patients with grade ≥3 ICI-related pneumonitis (i.e. requiring hospitalization) have high mortality rates and this was consistent with our findings. Treatment for ICI-related pneumonitis was started >2 days from admission in our study population. A high index of suspicion is necessary to expedite work-up, and a multidisciplinary approach is key to confirm diagnosis and promptly initiate treatment. Readmission rate was high. Care coordination and strategies for safe transitions of care at discharge should be ensured to improve the overall outcome.