Immune Checkpoint Inhibitor-Associated Acute Kidney Injury: A Single-Centre Study.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have improved cancer outcomes but can cause immune-related adverse effects (irAEs), including acute kidney injury (AKI). Limited Australian data exists regarding ICI-associated AKI (ICI-AKI). This observational study is aimed to describe the incidence, risk factors, and outcomes of ICI-AKI at Southern Adelaide Local Health Network (SALHN), South Australia. METHODS: Adult patients receiving ICI therapy at SALHN between January 2020 and December 2023 were included. Clinical and laboratory data were collected from electronic medical records. ICI-AKI was defined as AKI that led to the delay or discontinuation of ICI therapy due to clinical concern, biopsy-proven ICI-related tubulointerstitial nephritis, or corticosteroid-treated suspected ICI-AKI. Data on kidney biopsy findings, corticosteroid use, ICI rechallenge, AKI recurrence, and renal recovery were assessed. RESULTS: Among 507 patients, 58 (11.4%) developed AKI, with 11 cases (2.2%) attributed to ICIs. Ipilimumab use and lower baseline eGFR were associated with higher AKI and ICI-AKI risk, while durvalumab was associated with lower AKI risk. Median time to AKI onset was 83 days post-first ICI cycle. Corticosteroids were initiated in eight patients for a median of 154 days. Four patients underwent kidney biopsy (median 106 days post-AKI), all showing tubulointerstitial nephritis. Four patients were rechallenged with ICIs; one had recurrent AKI. One patient required dialysis, and two achieved complete renal recovery. CONCLUSIONS: In this first Australian study examining all forms of cancer, ICI-AKI occurred infrequently, but had a significant clinical impact. Ipilimumab exposure and impaired baseline kidney function were key risk factors.