The KEYNOTE-671 trial is a phase III trial in which patients with early-stage non-small cell lung cancer were randomised to receive perioperative pembrolizumab plus chemotherapy followed by surgery, or chemotherapy followed by surgery alone. The objective of this trial was to demonstrate the benefit of adding perioperative pembrolizumab in terms of efficacy, event free survival and overall survival and pathological complete response. This was a positive trial because those patients receiving perioperative pembrolizumab had a significant benefit in terms of event free survival, overall survival and pathological complete response.

What was the study design for this subgroup analysis?

Today we have presented the five-year update of patients with pathological complete response following treatment with induction pembrolizumab and chemotherapy or chemotherapy followed by surgery.  There was a previous exploratory analysis during the first interim analysis in which patients with pathological complete response seemed to have an increase in event free survival. Today what we have presented is that those patients with pathological complete response in the pembrolizumab arm had less progressive disease, less patients had to receive subsequent therapies and also the event free survival rate in those patients with pathological complete response was longer, with a five-year event free survival rate of 81% in the pembrolizumab arm versus 56% in the placebo arm.

What could be the clinical significance of these results?

The fact is that currently we don’t know which patients benefit from adjuvant treatment after induction treatment and surgery. We know that those patients with non-pathological response that are also being presented today by Dr Reck, those patients also benefit from receiving adjuvant pembrolizumab and also patients with pathological complete response have an increase in event free survival when they receive pembrolizumab. So this highlights the benefit of adjuvant treatment after induction but we still don’t know which patients benefit most from this strategy.

What’s next for this study?

These results highlight the importance of the perioperative strategy. To decide which are the patients that benefit most of this strategy, maybe we have to include molecular determinants that can help us. Also probably ctDNA will also be helpful. So to introduce these kinds of determinants will be also very useful for us.