Sandrine Faivre, MD, PhD

Commenting on these study results, formal discussant Sandrine Faivre, MD, PhD, of Bichat-Beaujon University Hospitals Paris Nord Val de Seine, Paris, France, said: “It is a challenge to identify patients who we should allow to remain on immune checkpoint inhibitor treatment. In KEYNOTE-040, the highest benefit was observed in those with a programmed cell death ligand 1 (PD-L1) tumor proportion score > 50% in the tumor—only 26% of the population. In this group, the benefit in survival was strong, and the drug delayed disease progression.”

The U.S. Food and Drug Administration approval of pembrolizumab (Keytruda) for previously treated lung cancer required a PD-L1 tumor proportion score ≥ 1% and for previously untreated lung cancer, a tumor proportion score ≥ 50%, but pembrolizumab was approved for head and neck squamous cell carcinoma without the requirement for PD-L1 testing, she continued.

“The median time to response with pembrolizumab [in this trial] was 4.5 months. It is tricky, because patients need more time to reach an objective response, but once they respond, median duration of response of 18 months is remarkable. This is more frequent in the high PD-L1 expressors: the objective response rate of 26% vs 9.2% with the standard of care, compared with the intent-to-treat analysis of 14.6%. This subgroup [of PD-L1 high expressors] is exquisitely sensitive to pembrolizumab,” Dr. Faivre said. ■

DISCLOSURE: Dr. Faivre is a consultant for and has received clinical trial grants from Bristol-Myers Squibb, Bayer Pharma, Eli Lilly, Ipsen, MSD, Merck Serono, and Novartis.