CHICAGO – The PD-1 inhibitor, pembrolizumab, is superior to docetaxel in prolonging overall and progression-free survival in patients with non–small cell lung cancer (NSCLC), according to the results of the phase III KEYNOTE-010 trial.
Furthermore, increasing PD-L1 expression was associated with more favorable outcomes with pembrolizumab while level of PD-L1 expression had no effect on outcomes in docetaxel.
Dr. Paul Baas
Results of the KEYNOTE-010 study were published earlier this year in the Lancet, but the results reported at the annual meeting of the American Society of Clinical Oncology further categorized study participants by tumor proportion score, a measure of viable tumor cells showing partial or complete membrane staining for PD-L1.
This finding verifies PD-L1 as a “predictive biomarker for ‘pembro’ in NSCLC,” lead study author Dr. Paul Baas of the Netherlands Cancer Institute, Amsterdam, said.
Out of 690 patients receiving pembrolizumab, 184 had a tumor proportion score (TPS) of 75% or more. For those 184 patients, median overall survival was 16.6 months and median progression-free survival was 6.2 months. The overall response rate was 33.7% for patients receiving pembrolizumab with TPS greater than 75%.
These survival and response rates were significantly higher, compared with the 8.2 month median overall survival, 4.0 month progression-free survival, and 7% overall response rate observed in 100 patients with the same TPS score who instead received docetaxel (overall survival: hazard ratio, 0.51; 95% confidence interval, 0.36-0.73; P less than .0001; progression-free survival: HR, 0.52; 95% CI, 0.38-0.69; P less than .0001; overall response rate: P less than .0001).
For the 106 patients receiving pembrolizumab who had a TPS between 50% and 74%, median OS was 15.8 months, PFS was 4.3 months, and the ORR was 22.6%. Median overall survival was significantly higher for pembrolizumab than docetaxel which was 8.2 months (HR, 0.58; 95% CI, 0.36-0.95; P = .01). ORR was also significantly higher for pembrolizumab than for docetaxel, which was 9.6% (P = .01).
The KEYNOTE-010 study was funded by Merck Sharp & Dohme. Dr. Baas reported having a consulting or advisory role and receiving honoraria and financial compensation from multiple companies including Merck Sharp & Dohme.