Pembrolizumab (Keytruda) has been approved for use before and after surgery in adults with resectable, locally advanced head and neck squamous cell carcinoma (HNSCC) whose tumors express PD-L1 (CPS ≥1).
The treatment plan includes pembrolizumab alone before surgery, followed by pembrolizumab with standard radiation therapy (with or without cisplatin) after surgery, and continued pembrolizumab afterward.
Results from the phase 3 KEYNOTE-689 trial, which showed that pembrolizumab significantly improved event-free survival compared with standard treatment alone. Patients with PD-L1 CPS ≥1 had a median event-free survival of 59.7 months versus 29.6 months for the control group, representing a 30% reduction in risk of disease progression or death. Among those with higher PD-L1 expression (CPS ≥10), the benefit was even greater.
Side effects were similar between groups, with about 81% of patients experiencing some treatment-related effects. Severe side effects (grade 3 or higher) occurred at similar rates in both groups, though serious events and treatment discontinuations were slightly higher.
Overall, this marks an important step in expanding the role of immunotherapy for patients with locally advanced HNSCC.