Immunological and clinical profiles of patients with advanced or metastatic melanoma receiving immune checkpoint inhibitors to investigate potential biomarkers for immune-related adverse events.
e14037 Background: Immune-related adverse events (irAEs) related to immune checkpoint inhibitors (ICIs) may target any organ and originate from autoreactive T cells injuring host tissues. There is a need to develop prognostic and predictive biomarkers to distinguish patients (pts) who will benefit from ICIs avoiding irAEs during treatment. We propose that irAEs are the result of many biological variables. We hypothesize that within each pts complex immunological profile, there may be patterns and associations which exist that represent a state of inflammation that is present prior to ICI therapy and hypothesize this could predict irAEs development. Methods: We created individual immunological profiles of 11 pts diagnosed with MM prior to receiving ICIs. Assays included: PBMC composition, circulating chemokines/cytokines, and IκB degradation status. CD4 and CD8 T cells were studied for their phenotype, activation status, proliferative capacity and cytolytic granules. Clinical data was collected on a larger MM pt cohort (n = 41) and descriptive statistics were utilized to characterize reported irAEs . Results: 110 input markers were utilized for immune signature analysis. 6 of the 11 pts reported grade 2+ irAEs after ICI therapy. The pro-inflammatory CCL13, CCL1, FLT-3, IL12p40, TRAIL, and granzyme b expressing CD4 T cells at steady state and after CD3 activation were significantly higher in pts with irAEs. Known inflammatory suspects (i.e., IL-2, IL-15, TNF-a or % CD8 T cells) were not associated with irAE development . A rank correlation test showed significant associations between the levels of these factors. irAEs were reported in 41% (n = 17) for our larger cohort, most frequently skin rash (7%), colitis (7%), hepatitis (7%) and thyroid dysfunction (4%). Conclusions: The immune signatures of pts with irAEs are highly heterogeneous and possess distinctive immunological patterns. Our results introduce possible molecular mechanisms that may aid understanding of irAE development, perhaps providing the basis for a new model prospectively testing these markers to risk stratify pts receiving ICIs.