[Correspondence] CheckMate 8HW and the future of dual immunotherapy

The phase 3 CheckMate 8HW trial, in patients with microsatellite instability-high or mismatch repair-deficient metastatic colorectal cancer, showed superior progression-free survival with nivolumab–ipilimumab versus nivolumab monotherapy across all treatment lines (hazard ratio [HR] 0·62, 95% CI 0·48–0·81, p=0·0003).1 However, it is unclear if patients with PD-L1-positive tumours benefit from the addition of ipilimumab. Figure 3 suggests lower benefit in the PD-L1 expression of 1% or higher subgroup (HR 0·77) compared with the PD-L1 expression of less than 1% subgroup (HR 0·57).