What happened, in summary

A 68-year-old Japanese man had non-small cell lung cancer associated with paraneoplastic arthritis. His cancer treatment began with radiotherapy and combination chemotherapy using carboplatin and paclitaxel, followed by durvalumab immunotherapy. Five months before a later hospital admission, he developed organizing pneumonia that was considered an immune-related side effect of durvalumab. Durvalumab was temporarily stopped and prednisolone improved the lung inflammation, but the pneumonia later recurred.

One month before admission, he developed marked protein loss in the urine and swelling of both legs. A kidney biopsy showed extensive inflammation and injury affecting the kidney filters and surrounding tissue. The findings were considered consistent with nephrotic syndrome caused by an immune-related reaction to durvalumab. Because of the kidney problem, durvalumab was discontinued. Supportive kidney medicines were tried, with losartan stopped after it caused low blood pressure and finerenone later used.

His proteinuria and low albumin gradually improved without a major increase in steroid treatment. At the latest follow-up, he remained alive at 200 weeks, and the improvement in his kidney findings had been sustained.