Purpose: To determine the incidence and types of irAEs seen in the ED at VA San Diego Healthcare System (VASDHS).
Background: ICPIs activate T-cells against many tumor types, but they also cause irAEs, which can lead to organ dysfunction. With the increasing use of ICPIs, more patients are visiting the ED due to irAEs. ED providers should be familiar with irAEs to prevent misdiagnosis and further complications.
Methods: This was a retrospective study that included patients who received at least one dose of ipilimumab, nivolumab, pembrolizumab, atezolizumab, durvalumab, or any ICPI combination. The primary outcome was the incidence/types of irAEs seen in the ED. Secondary outcomes included: percent of irAEs leading to hospital admission, percent of ED providers aware of ICPI therapy, and rate of ICPI discontinuation due to irAEs. Patients who experienced severe irAEs (irAEs that warranted an ED visit or ICPI discontinuation) were compared against those who didn’t to identify risk factors. Chi-square and Mann-Whitney U tests were used to compare categorical and continuous data, respectively.
Results: Out of 151 patients who received ICPIs, 22 experienced severe irAEs. Patient characteristics were similar except: more patients in the irAE group were diagnosed with melanoma and had received ipilimumab or >1 ICPI. A total of 246 ED visits were documented: 14 patients made 16 ED visits (6.5%) due to irAEs including colitis, hypophysitis, and hypothyroidism; 15 visits (93.8%) led to hospital admission, and 14 ED providers (87.5%) were aware of ICPI therapy. Ipilimumab and ipilimumab/nivolumab were the most recent ICPIs administered before an irAE. ICPIs were discontinued in 15 patients due to irAEs, 7 of which stopped after an ED visit.
Conclusion: The rate of irAE-related ED visits at VASDHS was lower than published literature (6.5% vs. 25%) which may have been due to small sample size. Most irAEs were associated with ipilimumab and combination ICPIs, similar to previous studies. Most ED providers were aware of ICPI therapy leading to appropriate diagnosis of irAEs. Risk factors for severe irAEs may include treatment with ipilimumab or >1 ICPI. Continuous education of ED staff regarding ICPIs and irAEs is recommended to ensure appropriate diagnosis and treatment.
