P0306ACUTE KIDNEY INJURY AFTER CHECKPOINT INHIBITOR TREATMENT: FACING THE FUTURE

Abstract

Abstract Background and Aims Checkpoint inhibitors (CPI) are used to treat solid organ metastatic malignancies. They act on by triggering a vigorous immune response against tumoral cells, preventing their proliferation. CPIs reinvigorate antitumor immune responses by interrupting co-inhibitory signaling pathways and promote immune-mediated elimination of tumor cells.This is not a selective response, deriving in immune related adverse events (irAEs). The kidney can potentially be damaged with an incidence of 13-29%. The most frequent type of toxicity is acute interstitial nephritis (AIN). Method We evaluated all the patients with solid organ metastatic malignancies treated with immunotherapy that developed acute renal injury (AKI) and underwent to kidney biopsy from March 2018 to November 2019 at Vall d’Hebron University Hospital. Results 11 patients with solid organ metastatic malignancies treated with immunotherapy developed AKI and underwent to kidney biopsy during the study period. The most frequent malignancy was lung cancer - in 6 patients-, followed by 3 patients with melanoma. 8 patients (72%) had already received previous oncological therapy, and for the remaining 3 patients (27%), CPI was the first line therapy. 8 patients (72%) were treated with anti-PD1 (programmed cell death protein 1), 4 patients (36 %) received anti PDL-1 (programmed death-ligand 1) 1 of these patients in combination with an anti CTLA-4 (cytotoxic T-lymphocyte antigen 4) and another patient received both anti PD1 and anti PDL-1. The time between the start of CPI and the onset of the AKI ranged between 2-11 months. The most frequent urine findings were subnephrotic range proteinuria with a mean protein/creatinine (mg/g creatinine) 503.6 ± 190.5 and leukocyturia in 9 of 11 patients. Mean creatinine (mg/dl) at diagnosis was 3.4 ± 1.3. 10 out of the 11 patients were diagnosed of AIN after performing a kidney biopsy. The remaining patient presented chronic changes (IFTA and glomerulosclerosis) in the biopsy, performed after receiving steroids for a month. 3 patients who presented AIN received pulses of methylprednisolone 250-500mg as induction treatment and 7 patients received prednisone 1mg/kg/day. Mean prednisone accumulated dose (mg) during the first month of treatment was 1387.5 ± 540. 9 patients experienced complete recovery of kidney function and two patients progressed to CKD. Conclusion We reported 11 patients who presented AKI associated to CPI treatment and underwent to kidney biopsy in the last 20 months at our center. 10 out of 11 presented biopsy confirmed CPI related AIN. In our experience, CPI related AIN is the most frequent renal lesion associated to the novel immunotherapy treatments. This entity seems to have good renal prognosis as long as steroid treatment is early started.