Case Series of the Use of Infliximab in the Treatment of Immune Checkpoint Inhibitor-Associated Acute Interstitial Nephritis

Introduction: Immune checkpoint inhibitors (ICIs) have become a widely utilized therapy for various malignancies. However, their use is associated with immune-related adverse events, including acute kidney injury (AKI), often secondary to acute interstitial nephritis (AIN). ICI-associated AIN is typically managed with glucocorticoids (GCs) and discontinuation of the offending agent. However, some patients exhibit only a partial response to GCs or experience relapses, resulting in steroid dependence. Infliximab, a tumor necrosis factor-alpha (TNF-α) inhibitor, has been effectively used to manage other ICI-related toxicities such as colitis and arthritis. A 2021 case series suggested infliximab may be beneficial as an adjunct to GCs in patients with relapsing ICI-AIN; however, data on its use for this indication remains limited. Case Description: We describe six patients who developed AKI while undergoing ICI therapy, attributed to AIN either by biopsy confirmation or based on clinical criteria (e.g., temporal association with ICI use and absence of alternative etiology of AKI). All patients received GCs as initial therapy, followed by adjunctive treatment with infliximab. Five of the six patients tolerated infliximab without significant adverse effects, demonstrated improvement in renal function, and were successfully weaned off steroids, maintaining stable kidney function during follow-up. One patient did not respond to GCs or infliximab and experienced adverse effects from infliximab, leading to its discontinuation. Details of individual cases are displayed in the attached table. Discussion: Although the data is currently limited to case series, these findings support that infliximab may be a promising adjunctive therapy for ICI-associated AIN, particularly in patients with GC-refractory or relapsing disease. It may facilitate durable renal recovery while reducing prolonged GC exposure.