We present a case of pseudo acute kidney injury (AKI) following capmatinib therapy in an 84-year-old male with combined non-small cell (adenocarcinoma) and small cell lung cancer with MET Exon 14 skipping mutation. His past medical history was significant for chronic kidney disease (CKD) stage 3 with a baseline serum creatinine (SCr) of 1.6 mg/dl rising to 2.44 mg/dL [estimated glomerular filtration rate (eGFR) 24 mL/min/1.73m] while on capmatinib. SCr improved to 1.84 mg/dL with the cessation of capmatinib but rose again to 2.22 mg/dL upon resumption of therapy. Further investigation with Cystatin C and renal iothalamate clearance showed that despite fluctuation in SCr levels, there was not much variation in GFR calculated using these methods. Urinalysis and urine protein-to-creatinine ratio were unremarkable. Treatment with capmatinib was continued at reduced dose and a third instance of rise in SCr was observed followed by a spontaneous return to baseline. Thus, MET inhibitor therapy can result in an asymptomatic rise in SCr, and it must be distinguished from AKI with more accurate noncreatinine-based measures to evaluate GFR. This could spare such patients from invasive diagnostic tests, such as a kidney biopsy, and premature cessation of prognostically important cancer therapies.Copyright © 2021. Published by Elsevier Inc.
