Appropriate Analysis of Duration of Response Data in Cancer Trials

To the Editor We read with interest the recent Original Investigation by Reardon et al¹ reporting results of the CheckMate 143 randomized clinical trial, which compared nivolumab with bevacizumab among patients with recurrent glioblastoma. For the end points of overall survival, progression-free survival, and objective response rate, nivolumab was either inferior or neutral to bevacizumab. The only signal potentially favoring nivolumab was from the duration of response (DOR),¹ as underscored in the accompanying Editorial.² The reported median DORs were 11.1 and 5.3 months for nivolumab and bevacizumab, respectively. However, this comparison might not be appropriate because these 2 medians were based on the DORs among responders only, and the objective response rates of the 2 treatment groups differed substantially: 7.8% for nivolumab vs 23.1% for bevacizumab.¹