A case of biopsy-proven acute interstitial nephritis following atezolizumab-bevacizumab treatment of advanced unresectable hepatocellular carcinoma.

backgroundThe advent of immune checkpoint inhibitors (ICIs) represented a significant breakthrough in cancer therapy. Recently, the combined use of atezolizumab and bevacizumab was approved as first-line treatment for unresectable hepatocellular carcinoma (HCC). Exposure to a novel and diverse spectrum of immune-related adverse events (irAEs) has increased with the growing utilization of ICIs, however, a comprehensive understanding surrounding newer agents is still lacking. The incidence of kidney toxicities is rare but rising, often underreported due to the lack of confirmatory biopsies. Here, we present a rare case of biopsy-proven acute interstitial nephritis (AIN) following atezolizumab-bevacizumab treatment of advanced unresectable HCC. CASE: An 84-year-old male with T4N0M0 hepatocellular carcinoma was admitted after cycle 5 of atezolizumab due to decreased urine output and dysuria with a serum creatine of 4.7 mg/dL compared to a baseline of 1.3 mg/dL. To confirm the diagnosis of possible intrinsic renal injury, an ultrasound-guided non-focal biopsy of the left kidney was performed, revealing AIN. Potential exacerbatory medications, such as proton-pump inhibitors, were discontinued. The patient was discharged on oral steroids with improvement in serum creatinine. Before completing the steroid taper, the patient developed pneumocystis pneumonia and eventually transitioned to hospice care.

conclusionThis case highlights the valuable role renal biopsy can play in accurately capturing irAEs and guiding appropriate management in the setting of ICI-induced AKI. It also exemplifies important considerations for steroid treatment of irAEs in the setting of comorbidities, such as diabetes.