Merck announced the first-time presentation of findings investigating the use of KEYTRUDA® (pembrolizumab), the company’s anti-PD-1 therapy, as a monotherapy in patients with advanced unresectable nasopharyngeal carcinoma (NPC) – a type of head and neck cancer – whose tumors express PD-L1 (≥1% of cells in tumor nests or PD-L1+ bands in stroma). Data were from a Phase 1b study (KEYNOTE-028) and showed an overall response rate (ORR) (confirmed and unconfirmed) of 22.2 percent (95% CI, 8.6-42.3) in evaluable patients (n=27) who were treated with KEYTRUDA.
Merck has initiated a comprehensive clinical development program evaluating KEYTRUDA in head and neck cancer across multiple lines of therapy as monotherapy and in combination with chemotherapy as well as other agents. In KEYNOTE-028, KEYTRUDA is being evaluated in patients with advanced unresectable NPC that is not responding to current therapy or for which current therapy is not appropriate. This is the second study to show early activity of KEYTRUDA in patients with head and neck cancer and the first study of an anti-PD-1 therapy to demonstrate clinical activity in patients with recurrent or metastatic NPC.
PD-L1, also called programmed death-ligand 1, is a protein expressed on many types of cells, including some cancer cells. Under normal conditions, the interaction of PD-L1 with another protein, called programmed death receptor-1 (PD-1), serves as an important immune system checkpoint, keeping the immune system in balance and preventing the body from attacking its own cells when inflammation or an infection is present. When cancerous tumors express PD-L1, however, they are able to escape detection and destruction by cytotoxic T-cells – a type of cancer-killing immune cell – allowing the tumor to survive and grow. Tumor PD-L1 expression has been observed at varying levels across many tumor types, including breast, lung, bladder cancer, and nasopharyngeal carcinoma. High levels of PD-L1 expression, called overexpression, are under investigation for potential use as a way to help identify patients with an enhanced likelihood to respond to certain immune-based treatment approaches.
