Reanalysis of urothelial cancer chemoimmunotherapy trial with differential censoring

Three similar phase 3 randomized clinical trials have investigated PD-1/PD-L1 inhibitors in combination with platinum-based chemotherapy versus chemotherapy alone as first-line treatment for advanced urothelial carcinoma (IMvigor130, atezolizumab; KEYNOTE-361, pembrolizumab; and CheckMate 901, nivolumab). Only CheckMate 901 reported overall survival benefit for the combination. The reason for these inconsistent results is unclear. A comparative effectiveness reanalysis of the studies investigated whether differential censoring could explain this inconsistency. The analysis found that differential censoring with increased censoring in the chemotherapy-alone group was present for overall survival only in CheckMate 901. After adjusting for it, the significance for the overall survival benefit reported for CheckMate 901 was lost. The authors conclude that these findings suggest that differential censoring could explain inconsistent results between trhee similar trials.