Favorable results for pembrolizumab, a PD-1/PD-L1 inhibitor only recently approved for the treatment of non-small-cell lung cancer (NSCLC), were found in a trial comparing the drug’s effectiveness to that of the chemotherapy drug docetaxel, the current standard of care, in patients with NSCLC.
In the study, 1034 NSCLC patients with PD-L1 expression on at least 1% of tumor cells were randomly assigned into three treatment groups: a low-dose (2 mg/kg) pembrolizumab arm (n=345), a high-dose (10 mg/kg) pembrolizumab arm (n=346), and a docetaxel arm (n=343). Treatments were administered every 3 weeks during the 2-year study period.
Median overall survival of patients was 10.4 months with low-dose pembrolizumab, 12.7 months with high-dose pembrolizumab, and just 8.5 months with the current standard docetaxel. There were no significant differences in progression free survival between patients in each treatment group.
Further, an even greater improvement in overall survival was found in patients for whom at least 50% of their tumors expressed PD-L1 (14.9 months and 17.3 months with low-dose and high-dose pembrolizumab, respectively, versus 8.2 months with docetaxel), indicating that the drug is more highly effective in this patient population.
In addition, pembrolizumab was better tolerated than docetaxel. Grade 3–5 treatment-related adverse events were reported by 35% of patients treated with docetaxel and only 13% and 16% of patients treated with low-dose and high-dose pembrolizumab, respectively.
Top-line results from the study had been announced by Merck, the drug’s manufacturer, in October. The full study was published on December 19 in The Lancet.
Investigators concluded that there is a clear benefit of using pembrolizumab for NSCLC patients who express PD-L1 in at least 1% of their tumors. The findings confirm the importance of using biomarkers like PD-L1 to aid in the selection of the most appropriate treatments for patients.
