The FDA approved pembrolizumab (Keytruda, Merck) as monotherapy for certain patients with recurrent locally advanced or metastatic squamous cell carcinoma of the oesophagus (ESCC).
The approval indicates the usage of pembrolizumab for patients whose tumours express PD-L1, with a combined positive score of 10 or higher, as determined by an FDA-approved test, and who experienced disease progression after one or more previous lines of systemic therapy.
The approval was based on data from KEYNOTE-181, a multicentre, randomized trial involving 628 patients with recurrent locally advanced or metastatic oesophageal cancer who progressed on or after one prior line of systemic treatment for advanced disease.
All patients were required to have tumour specimens for PD-L1 testing at a central laboratory, where PD-L1 status was determined using the PD-L1 IHC 22C3 pharmDx kit (Agilent).
An improvement in overall survival was found in patients whose ESCC tumours expressed PD-L1 who were randomly assigned to receive pembrolizumab versus chemotherapy.
In ESCC patients with PD-L1 expression, the median overall survival was 10.3 months in patients receiving pembrolizumab (95% CI, 7-13.5 months) and 6.7 months in the chemotherapy arm (95% CI, 4.8-8.6 months) (HR, 0.64; 95% CI, 0.46-0.90).
The median progression-free survival was 3.2 months (range, 2.1-4.4 months) in patients receiving pembrolizumab and 2.3 months (range, 2.1-3.4 months) in those receiving chemotherapy (HR, 0.66; 95% CI, 0.48-0.92).
A higher percentage of pembrolizumab-treated patients achieved response (22% vs. 7%), complete response (5% vs. 1%) and partial response (18% vs. 6%). Median duration of response was 9.3 months in the pembrolizumab group and 7.7 months in the chemotherapy group.
“Historically, patients with advanced oesophageal cancer have had limited treatment options, particularly after their disease has progressed,”said Jonathan Cheng, MD, vice president for oncology clinical research at Merck Research Laboratories, in a press statement.