US pharmaceutical company Merck & Co Inc (NYSE:MRK), known as MSD outside the US and Canada, announced on Friday that the US Food and Drug Administration has approved KEYTRUDA (pembrolizumab) as a perioperative treatment for adults with resectable locally advanced head and neck squamous cell carcinoma whose tumours express PD-L1 (CPS ≥1).

This marks the first approval of an anti-PD-1 therapy for use both before surgery as a neoadjuvant and after surgery as adjuvant treatment combined with radiotherapy, with or without cisplatin, followed by KEYTRUDA monotherapy.

The approval is based on results from the Phase 3 KEYNOTE-689 trial, which showed a 30% reduction in risk of recurrence, progression, or death compared to standard adjuvant care.

Median event-free survival in the PD-L1 positive population was nearly doubled in the KEYTRUDA arm -- 59.7 months versus 29.6 months.

The new indication was reviewed under Project Orbis, enabling parallel regulatory reviews in countries including Canada, Australia, and Brazil.

Marketing applications based on KEYNOTE-689 data are currently under review in several international markets, including Europe and Japan.

KEYTRUDA is already approved in the United States for multiple indications in recurrent or metastatic head and neck squamous cell carcinoma.

Merck emphasised the potential of this new regimen to significantly impact treatment strategies for eligible patients.