What happened, in summary

A 73-year-old Japanese man with advanced lung adenocarcinoma began first-line pembrolizumab, cisplatin, and pemetrexed. He was not taking another medicine considered directly nephrotoxic. Seven days after the first treatment, laboratory testing showed that his creatinine had increased from 1.17 to 1.68 mg/dL.

His kidney function continued to decline, prompting a renal biopsy on day 16. The biopsy showed mild acute tubular injury rather than severe interstitial inflammation. Because the injury was considered limited, he received a shorter corticosteroid course than some of the other patients in the case series. Prednisone was started at 30 mg daily and continued for one month.

The treatment improved the acute kidney injury, although creatinine remained mildly elevated at approximately 1.4–1.5 mg/dL during follow-up. His lung-cancer regimen was subsequently changed, and he began carboplatin with nab-paclitaxel.

His experience illustrates that kidney injury can appear within days of combined immunotherapy and chemotherapy. Biopsy helped distinguish the relatively mild tubular injury and supported a shorter prednisone course, while the oncology team selected a different systemic regimen so cancer treatment could continue.