Analyzing immunotherapy adverse events in elderly cancer patients.

Abstract

e24009 Background: Immunotherapy (IT) has cemented itself as a mainstay in cancer treatment, especially in those with late stage malignancies. Generally, these agents are well tolerated, but there is a known association with immune-related adverse events (iRAE). Due to an underrepresentation of elderly patients in clinical trial data, it is valuable to understand the tolerance of these agents. The primary objective of our study was to evaluate for an association between older age, defined as age 75 and above, and increased risk for iRAE in a real-world population. Methods: We performed a retrospective study utilizing data from elderly patients (pts) who had first received IT (specifically Pembrolizumab, Nivolumab, Atezolizumab, Avelumab, and Durvalumab) from 01/01/2015 through 12/31/2019. This subset of pts were followed until 12/31/2021. Descriptive analyses were performed to identify iRAE patterns. A chi-square test or a Fisher’s exact test was used to test for associations in bivariate comparisons while a two-sample t-test was used to test for differences in continuous variables between age groups > 75 to 79 years (Group 1) and > 80 years (Group 2). Statistical significance was determined by p < 0.05 unless otherwise noted. Results: 103 pts qualified for assessment over the study period. Group 1 had a total of 48 pts with a median age of 77. Group 2 had a total of 55 pts with a median age of 84. The study had 57 males and 46 females. 96 pts were Stage IV and 7 pts were Stage III. The most prevalent malignancies in the study were lung, skin, and renal cancer. Treatment intent was palliative for 96 pts, adjuvant for 6 pts, and neo-adjuvant for 1 pt. Overall, there were 72 pts with reported iRAE and 31 pts without reported iRAE. Of the pts with iRAE: 7 pts required outpatient observation without intervention, 38 pts required outpatient intervention(s), 19 pts were hospitalized, and 8 pts required ICU level of care. There was one death due to complications from encephalitis associated with hypophysitis and hyperthyroidism. Regarding discontinuation of IT for pts: 42 pts transitioned to hospice, 35 pts had progression of disease, 8 pts finished their treatment regimen, 5 pts developed an alternative diagnosis, and 9 pts discontinued due to iRAE. Nine pts in the study required corticosteroids for their iRAE. There was no statistically significant difference in incidence of any iRAE (regardless of type) between the two age groups 75-79 and over 80 years (p-value = 0.3703). Similarly, there was no difference for sub-categories including stage of cancer, type of cancer, treatment intent, and severity of iRAE. Conclusions: Elderly pts over age 75 that received the aforementioned IT were shown to have relatively tolerable safety profiles regardless of their age group and the majority continued with IT despite iRAE. This study reinforces the notion that IT could be used in geriatric pts without fear of exposing this vulnerable age group to substantial rates of negative outcomes.