Limitations
tumor
TUMOR
Some limitations of this analysis include the small number of Japanese patients, especially for the analysis of patients with tumor PD-L1 expression of 1% or more. Furthermore, there was an imbalance in the number of patients randomized to nivolumab and placebo in Japan because the stratification factors did not include Japanese. A consequence of this is that some differences in prognostic characteristics between the two groups, including the stratification factors used for randomization, may confound the results.