Endocrine adverse events related to immune-oncology agents: retrospective experience of a single institution.

Background: Immune-oncology agents (IOA) represent a turning point in the treatment of several solid tumors (ST). Although their toxicity compares favorably with other treatments, IOA associate immune-related adverse events (IR-AE), among which endocrine-related AE stand out. We retrospectively evaluated the occurrence of endocrine (E) IR-AE in a cohort of patients with several ST treated with IOA. In addition, we assessed the correlation between likelihood of survival and the occurrence of IR-AE.

Methods: We collected data on clinical and molecular characteristics, efficacy and AE of 260 patients with ST treated with IOA from 2013 to 2017. We excluded patients with prior conditions or treatments potentially affecting thyroid test results.

Results: Lung cancer was the most prevalent diagnosis (70.2%). EIR-AE appeared in 18.1% of patients (total of 38 EIR-AE) and consisted of hypothyroidism, hyperthyroidism, pituitary disorders and type 1 diabetes mellitus in 60.5%, 21.1%, 15.8% and 2.6% of patients, respectively. EIR-AE were associated mainly to nivolumab, nivolumab plus ipilimumab (41.2% and 26.5%) and appeared after a median of 4.2 cycles of treatment. Specific therapy was required in 65.8% patients. There were significant differences in both progression-free survival (PFS) and overall survival (OS) for patients who experienced EIR-AE compared to those who did not [PFS: 56.7 (NC-NC) 27.7 (14.3-41.3) months, P=0.008; OS: NC (NC-NC) 31.4 (20.7-42.1) months, P=0.001].

Conclusions: The incidence of EIR-AE in our study is similar to other series. Patients who develop EIR-AE might have a better prognosis compared to those who do not experience them.