PD-L1 expression in locally advanced or metastatic non-small cell lung cancer

In August 2019, Lung Cancer published the results of a global, multicenter, retrospective observational study. From 45 centers in 18 countries, 2617 patients with age (> 18 years), stage IIIB/IV NSCLC, and cancer tissue mass (< 5 years) collected before treatment were tested using the PD-L1IHC22C3 pharmDx kit (Agilent, Santa Clara, CA, USA).

Of 2617 eligible patients, 2368 (90%) had PD-L1 data:

530 patients (22%) had PD-L1 TPS (> 50%).

1232 cases (52%) had PD-L1TPS (> 1%).

1136 cases (48%) had PD-L1TPS < 1%.

The most common reason for the absence of PD-L1 data (n = 249) was the insufficient number of tumor cells (< 100) (n = 170 [6%]).

PD-L1 expression in NSCLC patients in different regions:

The proportions of patients with PD-L1 TPS (> 50%) and TPS (> 1%) in Europe were 22%/52%, respectively.

The Asia-Pacific region is 22%/53%.

America is 21%/47%.

Other countries accounted for 24/55 per cent.

The incidence of EGFR mutation (19%) and ALK mutation (3%) is consistent with previous reports of metastatic NSCLC. In 1064 patients with negative EGFR and ALK mutations, the incidence of PD-L1TPS (> 50%) and TPS (> 1%) were 27% and 53%, respectively.

This is the largest real-world study to date to evaluate late NSCLC PD-L1 expression using the 22C3 pharmDx kit. The detection failure rate is low. The incidence of PD-L1 TPS (> 50%) and TPS (> 1%) in patients with stage IIIB/IV NSCLC is similar in different regions of the world, which is basically consistent with the central test results of screening population in clinical trials.

Dietel M, et al. Real-world prevalence of programmed death ligand 1 expression in locally advanced or metastatic non-small-cell lung cancer: The global, multicenter EXPRESS study. Lung Cancer. 2019 Aug; 134: 174-179