INTRODUCTION: American Society of Clinical Oncology (ASCO) has developed guidelines on the management of immune-related adverse events (irAEs) associated with immune checkpoint inhibitors (ICPIs). However, many irAEs are under-reported and the studies to investigate predictive factors are limited with variable results.
METHODS: A total of 66 patients who received ICPIs at Stratton VAMC Albany between January 2015 to December 2018 were studied. Computerized Patient Record System (CPRS) was used to do a retrospective chart review to identify irAEs and related parameters. IRB approval was obtained.
RESULTS: Sixty-three patients received PD-1 inhibitors (62 males). Our study included 39 patients with lung, 10 renal, 6 head and neck, 4 skin (melanoma), and 2 bladder cancers, and 1 metastatic cancer with unknown primary. Median age of patients with irAEs was 69.5 years versus 66.7 years for patients without irAEs. 23 (36.5%) patients experienced 28 irAEs. 45 patients received nivolumab, 18 (40%) of which had 21 irAEs. 17 got pembrolizumab and 5 (35.2%) had 7 irAEs. Majority of the irAEs were grade I (n=10, 35.7%) or grade II (n=11, 39.2%), while 6 (21.4%) grade III and only 1 (3.5%) grade IV irAE was observed. Median time to appearance of irAEs was 2 cycles. Immunotherapy was continued in 12, temporarily held in 7 and permanently discontinued only in 4 patients. No death was attributed to irAEs. Six patients developed diarrhea, 4 hepatitis, 6 skin rash, 5 thyroid issues and 3 pneumonitis. Rare irAEs included cardiac tamponade (grade IV), uveitis (grade II), central adrenal insufficiency and mild neutropenia in one patient each. 2 patients had pre-existing autoimmune conditions (rheumatoid arthritis and chronic dermatitis), both had transient flares though immunotherapy was continued. Of note, only 3 patients received PDL-1 inhibitors and 1 developed grade II polymyalgia rheumatica and hypothyroidism.
Using multivariate logistic regression, we found no significant association between irAEs and age, body mass index, derived neutrophil to lymphocyte ratio, chronic kidney disease or environmental/medical allergies.
CONCLUSIONS: ICPIs were generally well tolerated in our population, though prompt recognition of rare and severe irAEs is essential. Larger studies are needed to investigate the predictive risk factors for irAEs.