Background and importance In naive treated populations with advanced non-small cell lung cancer (NSCLC), pembrolizumab monotherapy is the recommended option for patients whose tumours express PD-L1 with a tumour proportion score (TPS) ≥50%. In a population previously treated with platinum based chemotherapy double, pembrolizumab (PD-L1 1%) is a valid option in those who have not been treated with firstline immunotherapy.

Aim and objectives To analyse the effectiveness and safety of patients with NSCLC treated with pembrolizumab in clinical practice.

Material and methods This was a multicentre, observational, retrospective study carried out between January 2017 and June 2019. All patients with NSCLC undergoing treatment with pembrolizumab as monotherapy were included. Patient data were taken from the clinical records. Variables included were age, sex, stage, line of treatment, dose administered and functional status (PS) according to the ECOG scale. Efficacy endpoints was progression free survival (PFS) assessed by RECIST 1.1 criteria. Adverse events (AEs) were also assessed. Analysis of PFS was performed using the Kaplan–Meier curve.

Results Thirty-eight patients were included with NSCLC: 81.58% were men, mean age was 62.34±11.68 years, 97.36% (n=37) had ECOG PS 0–1 and 100% had NSCLC stage IV.

The percentage of patients who started pembrolizumab as firstline therapy was 50% and their tumours expressed PD-L1 ≥50% TPS, 42.10% had pembrolizumab as secondline therapy and 7.90% as thirdline therapy. The median administered dose was 160 mg (108–200); 8 patients (21.05%) are still receiving treatment. Causes of treatment suspension in the remaining patients were disease progression (60.53%) or death (18.42%). Median PFS of patients who started pembrolizumab as firstline therapy was 10 months (95% CI 7.1–12.92); in those treated as secondline and thirdline, median PFS was 4.2 months (95% CI 3.12–5.27).

AEs included asthenia grades 1–2 in 15.79%, arthralgia grades 1–2 in 13.16%, dermatitis in 7.89%, diarrhoea in 7.89%, hypothyroidism in 5.26%, pneumonitis in 5.26%, vomiting in 5.26%, anorexia in 5.26%, constipation in 5.26% and myalgia in 2.63%.

Conclusion and relevance Median PFS in our study was similar to the results of Keynote-024 (pembrolizumab as firstline treatment) 10 versus 10.3 months and Keynote-010 (pembrolizumab in previously treated patients) 4.2 versus 3.9 months. Pembrolizumab was safe and well tolerated; the safety profile was similar to that described in clinical trials.

References and/or acknowledgements 1. doi: 10.1016/S0140-6736(15)01281-7

2. doi: 10.1016/S1470-2045(17)30690-3.

No conflict of interest.