MO221ONLY A SIMPLE CASE OF AKI IN AN ONCOLOGIC PATIENT?
Authors: Giuliana Sofia , Ranieri Roberta , Ruosi Carolina , Cervesato Angela , Guerrera Luigi Pio , Troiani Teresa , Perna Alessandra , Capasso Giovambattista , Simeoni Mariadelina 
Published: May 2021

Abstract

Background
Nivolumab is a drug belonging to the class of Immune Checkpoint Inhibitors (ICPI), the use of which has improved the prognosis for patients with various advanced malignancies. These agents are associated with several "immune-mediated" adverse effects, although the literature on Nivolumab renal toxicity is poor and anecdotal. A rare immune-mediated renal adverse event is acute interstitial nephritis (AIN) that often imposes Nivolumab suspension.

Case report
We present the case of a 75-year-old woman with stage IV melanoma (inguinal and external iliac lymph node metastases without localization of the primitive lesion). At diagnosis, renal function was normal by age (Creatinine 0.89 mg/dl; CKD EPI eGFR 71 ml/min/1.73 m2). After lymphadenectomy, an adjuvant treatment with Nivolumab was initiated.
At 4-month follow-up, the patient was hospitalized for AKI (creatinine 2.6 mg/dl; eGFR 17,3 ml/min/1.73 m2). Although, renal function decline was not accompanied by signs of systemic immunoactivation, Nivolumab was suspended. In the following weeks, only a partial renal function recovery was observed, still limiting immunotherapy reintroduction. Thus, the patient was referred to our Onconephrology Outpatient Unit for a multidisciplinary approach. We performed a urinalysis with microscopy study of the sediment and observed rare dysmorphic red blood cells and leukocytes. To exclude a glomerulopathy, a comprehensive screening for autoimmune diseases and 24 hours proteinuria were also measured and found not significant (Table 1). Renal ultrasound did not show any relevant alteration.
Based on our original suspicion of AIN, although in absence of an history of fever, rush or eosinophilia, we introduced Prednisone 25 mg/day. In the following weeks, blood and urine tests showed a significant improvement in renal function (serum creatinine 1.06 mg/dL, eGFR CKD-EPI 51 mL/min/1.73m2) and the absence of red blood cells, leukocytes and proteinuria in the urinalysis.
Based on nephrologist advice, the patient was then able to resume the cancer treatment with a maintenance dose of prednisone equal to 5 mg/day.

Conclusion
AIN is a rare adverse effect of ICPIs that mandates the close monitoring of renal function in patients under immunotherapy with these agents.
AKI occurrence in patients treated with ICPIs should always lead to investigate a possible AIN, even in the absence of the classic symptom set of fever, rush and eosinophilia and with minimal changes in urinalysis. Based on our single observation, and after an accurate literature review, we suggest the initiation of a corticosteroid treatment in oncologic patients on an ICPI complicated with AKI and with suspicion of AIN at urinalysis.
Moreover, this case report thickens the importance of a multidisciplinary approach to oncologic patients not only when a conventional nephrotoxic chemotherapy has to be started, but also in case of ICIPs use. The nephrologist advice, in fact, could be useful in both preventing and treating severe renal complications such as AIN, also allowing the oncologic therapy maintenance.