Fifty-six patients with metastatic RCC were treated with nivolumab and included in the study. The investigators categorised the tumours into poorly proliferated (62.5%), moderately proliferative (30.4%), and highly proliferative (8.9%).
They found that the response rate was significantly lower among patients who had PD-L1 negative and poorly proliferated tumours (6.5%) than among those with PD-L1 negative and moderately proliferative tumours (30%).
The findings are preliminary because of the small number of patients included in the study. More research is needed to determine whether the 2 measures could be used as biomarkers in practice.