Immune checkpoint inhibitor-associated new-onset primary adrenal insufficiency: a retrospective analysis using the FAERS

BACKGROUND: Our study aimed to investigate the prevalence and demographic characteristics of immune checkpoint inhibitor-associated primary adrenal insufficiency (ICI-PAI) and to explore the risk factors of its clinical outcome using data from the US FDA Adverse Event Reporting System (FAERS). METHODS: This was a retrospective study. All cases of new-onset or newly diagnosed primary adrenal insufficiency associated with FDA-approved ICIs from 1 January 2007 to 31 December 2020 were identified and collected using FAERS. Data on age, sex category, body weight of the participating individuals, the reporting year and the prognosis of cases, and other accompanying endocrinopathies related to ICIs, were analysed. RESULTS: The incidence of ICI-PAI was 1.03% (1180/114121). Of the 1180 cases of PAI, 46 were “confirmed PAI”, and 1134 were “suspected PAI”. Combination therapy with anti-CTLA-4 and anti-PD-1 was related to a higher risk of PAI compared with the anti-PD-1-only group (χ(2) = 92.88, p < 0.001). Male and elderly individuals showed a higher risk of ICI-PAI (male vs. female, 1.17% vs. 0.94%, χ(2) = 12.55, p < 0.001; age < 65 vs. ≥ 65, 1.20 vs. 1.41%, χ(2) = 6.89, p = 0.009). The co-occurrence rate of endocrinopathies other than PAI was 24.3%, which showed a higher trend in patients on nivolumab-ipilimumab treatment than in those on PD-1 inhibitors (χ(2) = 3.227, p = 0.072). Body weight was negatively associated with the risk of death in the study population [p = 0.033 for the regression model; B = – 0.017, OR 0.984, 95% CI (0.969–0.998), p = 0.029]. CONCLUSION: ICI-associated PAI is a rare but important irAE. Male and elderly patients have a higher risk of ICI-PAI. Awareness among clinicians is critical when patients with a lower body weight develop PAI, which indicates a higher risk of a poor clinical outcome.