SUN-077 Immune Checkpoint Inhibitor-induced Hypophysitis In Adults: A Systematic Review Of Clinical Patterns And Hormonal Recovery

Abstract Disclosure: A.C. Bocato: None. L. Dotto: None. D.M. Santos: None. J.N. Silva Neto: None. F.G. Ecamila: None. A.L. Barbosa: None. A.C. Beatricci: None. B.R. Vieira: None. G.B. Soares: None. J.G. Alciati: None. Introduction: Immune checkpoint inhibitor-induced hypophysitis (ICI-H) is a significant endocrine toxicity related to oncologic immunotherapy, characterized by inflammation of the anterior pituitary and persistent hormonal dysfunction. This study aims to review the clinical manifestations of ICI-H in adults, focusing on the frequency of hormonal deficits, disease progression, and factors associated with either recovery or persistence of endocrine dysfunction. Methods: A systematic review was conducted in the PubMed, SciELO, and BVS databases, using MeSH descriptors and free terms related to immune checkpoint inhibitors, hypophysitis, and cancer. Primary clinical studies involving adult patients with clinical, hormonal, and/or imaging data related to ICI-H were included. Pediatric studies, studies without relevant clinical data, and those that addressed hypophysitis only as a secondary adverse event were excluded. Study quality was assessed using the Jadad and Newcastle-Ottawa Scales. Results: Nine studies were included. Most patients presented with adrenal axis deficiency as the main dysfunction, often without recovery during follow-up. Thyroid and gonadal axis dysfunctions were also observed, with partial recovery in a few cases. High-dose glucocorticoid therapy, evaluated in a clinical trial, did not improve pituitary function recovery and was associated with adverse metabolic effects. Patients receiving combined immunotherapy regimens (anti-CTLA-4 + anti-PD-1) showed a higher frequency and severity of hypophysitis. Some studies identified potential predictive markers, including hematologic and genetic alterations, as well as characteristic findings on imaging. Nevertheless, diagnostic criteria remain variable, and there is no consensus on optimal treatment strategies. Conclusion: ICI-H is a clinically relevant condition, often marked by abrupt hormonal dysfunction with incomplete recovery. Adrenal axis deficiency is predominant, and high-dose glucocorticoid therapy has not shown functional benefit. Identifying risk markers and standardizing diagnostic criteria are key priorities for the appropriate management of affected patients. Presentation: Sunday, July 13, 2025