Pembrolizumab provides benefit over ipilimumab in patients with advanced melanoma, regardless of tumor PD-L1 expression status or number of prior therapies, a study presented at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting has shown.1

The KEYNOTE-006 trial demonstrated that pembrolizumab provides superior overall and progression-free survival with a lower rate of grade 3 to 5 adverse events compared with ipilimumab in patients with advanced melanoma who have received no more than 1 prior therapy. Investigators sought to conduct an analysis of KEYNOTE-006 evaluating the impact of PD-L1 expression and prior therapy on outcomes.

The KEYNOTE-006 study enrolled 834 patients, of which 80% were PD-L1-positive and 18% were PD-L1-negative. Approximately two-thirds were treatment-naïve and the other one-third had previously received 1 line of therapy.

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Participants were randomly assigned to receive pembrolizumab 10 mg/kg IV every 2 or 3 weeks, or ipilimumab 3 mg/kg IV every 3 weeks. Pembrolizumab was given for 24 months or until disease progression or unacceptable toxicity, while ipilimumab was given for 4 cycles or until progression or intolerable toxicity.

Results showed that overall survival was improved with pembrolizumab in all subgroups expect those who were PD-L1-negative; however, the sample size in that group was small.

Researchers found that patients who were treatment-naïve and had PD-L1-positive tumors benefitted the most from pembrolizumab therapy.

The study further demonstrated that increasing PD-L1 expression was associated with improved outcomes with pembrolizumab vs ipilimumab when PD-L1 was scored as immunohistochemistry (IHC) 0 (0% staining), 1 ( < 1%), 2 (1%-9%), 3 (10%-32%), 4 (33%-65%), and 5 ( ≥ 66%).


1. Daud A, Blank CU, Robert C, et al. KEYNOTE-006 study of pembrolizumab (pembro) versus ipilimumab (ipi) for advanced melanoma: Efficacy by PD-L1 expression and line of therapy. J Clin Oncol. 2016; 34(suppl):Abstr 9513.