Do you recommend retreatment with an immune checkpoint inhibitor in a patient with a history of immune checkpoint inhibitor-related AKI that resolved with holding the immune checkpoint inhibitor and a glucocorticoid taper?  

Yes. You can rechallenge. The risk of recurrent AIN will be around 16 percent based on the largest study on rechallange. The odds are second time there will be no AKI.

There are case series in which patients who were diagnosed to have CPI AKI were re-challenged without recurrent ATIN. Importantly, not all patients had biopsy-proven ATIN so there could have been other causes of AKI besides ATIN. This highlights the importance of obtaining a renal biopsy in these pa...

Have to use clinical judgment. On the one hand, was immunotherapy effective against the cancer? On the other hand, how severe was the AKI? If you decide to restart immunotherapy, then close monitoring is needed, regardless of what the case series say about rechallenge's safety (or not).