Current status of first-line treatment with pembrolizumab for non-small-cell lung cancer with high PD-L1 expression.

It is not clear whether pembrolizumab monotherapy (MONO) or pembrolizumab plus platinum-based chemotherapy (COMB) should be selected for patients with advanced non-small-cell lung cancer (NSCLC) exhibiting high PD-L1 expression (tumor proportion score ≥ 50%). We performed a retrospective, multicenter study of 300 patients with NSCLC exhibiting high PD-L1 expression who received MONO or COMB as first-line treatment between December 2018 and January 2020. We reviewed the medical records of all consecutive patients with no driver mutations, and assessed the patient characteristics, therapeutic regimens, treatment periods, and adverse events. In total, 166 (55%; median age: 74 years) and 134 (45%; median age: 68 years) patients received MONO and COMB, respectively. Patients were younger and had better performance status (0-1) in the COMB group (p < 0.01). With a median follow-up time of 10.6 (range: 0.1-20.6) months, the median progression-free survival was 7.1 months with MONO and 13.1 months with COMB. The objective response rate was 42.2% with MONO and 67.9% with COMB. With respect to treatment discontinuation, 36 out of 166 (21.7%) and 28 out of 134 (20.1%) patients discontinued MONO and COMB, respectively. In conclusion, COMB may be a promising option for first-line treatment for NSCLC with high PD-L1 expression and good performance status.