Background: Cancer immunotherapy, such as anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and anti-programmed death 1 (PD-1), has revolutionized the treatment of malignancies by engaging the patient's own immune system against the tumor rather than targeting the cancer directly. These therapies have demonstrated a significant benefit in the treatment of melanomas and other cancers. Summary: In order to provide an extensive overview of the renal toxicities induced by these agents, a Medline search was conducted of published literature related to ipilimumab-, pembrolizumab-, and nivolumab-induced kidney toxicity. In addition, primary data from the initial clinical trials of these agents and the FDA adverse reporting system database were also reviewed to determine renal adverse events. Acute interstitial nephritis (AIN), podocytopathy, and hyponatremia were toxicities caused by ipilimumab. The main adverse effect associated with both the PD-1 inhibitors was AIN. The onset of kidney injury seen with PD-1 inhibitors is usually late (3-10 months) compared to CTLA-4 antagonists related renal injury, which happens earlier (2-3 months). PD-1 as opposed to CTLA-4 inhibitors has been associated with kidney rejection in transplantation. Steroids appear to be effective in treating the immune-related adverse effects noted with these agents. Key Message: Although initially thought to be rare, the incidence rates of renal toxicities might be higher (9.9-29%) as identified by recent studies. As a result, obtaining knowledge about renal toxicities of immune checkpoint inhibitors is extremely important.

Immune checkpoint inhibitors (ICIs) are increasingly used to treat cancers. Kidney immune-related adverse events (IRAEs) are now well recognized, with the incidence of IRAEs ranging from 2% to 5%. Most of the initial data related to kidney IRAEs have focused on acute interstitial nephritis (AIN). There are minimal data on the types and relative frequencies of glomerular diseases associated with ICIs, their treatment, and outcomes. We performed a systematic review and meta-analysis of all biopsy-proven published cases/series of glomerular pathology associated with ICIs. We searched the MEDLINE, EMBASE, and Cochrane databases from inception to February 2020. We abstracted patient-level data, including demographics, cancer and ICI therapy details, and characteristics of kidney injury. After screening, 27 articles with 45 cases of biopsy-confirmed ICI-associated glomerular disease were identified. Several lesion types were observed, with the most frequent being pauci-immune glomerulonephritis (GN) and renal vasculitis (27%), podocytopathies (24%), and complement 3 GN (C3GN; 11%). Concomitant AIN was reported in 41%. Most patients had ICIs discontinued (88%), and nearly all received corticosteroid treatment (98%). Renal replacement therapy (RRT) was required in 25%. Most patients had full (31%) or partial (42%) recovery from acute kidney injury (AKI), although 19% remained dialysis-dependent, and approximately one-third died. Complete or partial remission of proteinuria was achieved in 45% and 38%, respectively. Multiple forms of ICI-associated glomerular disease have been described. Pauci-immune GN, podocytopathies, and C3GN are the most frequently reported lesions. ICI-associated glomerular disease may be associated with poor kidney and mortality outcomes. Oncologists and nephrologists must be aware of glomerular pathologies associated with ICIs and consider obtaining a kidney biopsy specimen when features atypical for AIN are present.