A commentary discusses if it is time to embrace the routine use of immune checkpoint inhibitors in patients with advanced stage non-small-cell lung cancer? key questions related to the practical application of these agents remain, namely:
• Should they be given as second-line or third-line therapy?
• Is the biomarker of PD-L1 expression according to tumour proportion score reliable and should all patients be tested before starting treatment?
• What is the optimum dose of pembrolizumab in advanced stage non-small-cell lung cancer?
• Are they considered cost effective?
It is noted that before this study, the optimum dose of pembrolizumab for treatment of non-small-cell lung cancer was unclear. This study is the first and only study that shows a dose of 2mg/kg to be equally efficacious as 10mg/kg. The commentators wonder if treatment outcomes could be achieved with a dose lower than 2mg/kg, as a lower minimum effective dose could halve treatment costs for patients with low bodyweight if only one instead of two vials were needed per dose.
Pembrolizumab monotherapy was approved in the US in Oct 2015 for the treatment of patients with metastatic non-small cell lung cancer whose tumours express PD-L1 as determined by an FDA-approved test and who have disease progression on or after platinum-containing chemotherapy.
In the UK, pembrolizumab is currently only licensed as monotherapy for the treatment of advanced (unresectable or metastatic) melanoma in adults.