Keytruda shows benefit in head and neck cancer

EFS and mortality risk improved; efficacy demonstrated in the perioperative setting

Potential to close treatment gaps in locally advanced disease

The immunotherapy Keytruda has opened the era of early treatment for head and neck cancer by gaining approval as a perioperative therapy.

On December 2, MSD Korea held a media session to outline the clinical value of ‘Keytruda (pembrolizumab)’.

Last month, Keytruda received expanded approval for use as a perioperative therapy—both neoadjuvant and adjuvant—for patients with resectable, locally advanced head and neck squamous cell carcinoma (HNSCC). Keytruda was previously approved in 2020 as a first-line treatment for metastatic or recurrent HNSCC.

Professors Hye Ryun Kim, Hyun Jun Hong, Yonsei Cancer Center

This expanded approval is significant as it broadens the treatment paradigm, previously centered on traditional palliative approaches (first- and second-line treatment for recurrent/metastatic head and neck cancer), to include the preoperative stage. With its confirmed efficacy as adjuvant therapy in the highly recurrent and high-mortality locally advanced patient group, Keytruda’s expanded approval is expected to reshape treatment strategies.

The approval is based on results from the Phase III KEYNOTE-689 study in patients with Stage III or IVA HNSCC.

In the study, patients received Keytruda monotherapy (2 cycles) before surgery, followed by Keytruda plus radiotherapy (with cisplatin for high-risk patients) for 3 cycles after surgery, and then Keytruda monotherapy for up to 12 cycles.

Median follow-up of 38.3 months showed a 30% reduction in the risk of disease progression, recurrence, or death in the PD-L1-positive (CPS ≥1) patient group. The median event-free survival (EFS) was 59.7 months, more than double the control group's 29.6 months. The 3-year EFS also showed a gap of over 10 percentage points, with 58.2% in the Keytruda group versus 44.9% in the control group.

Although the median overall survival (OS) has not yet been reached, the risk of death was reduced by 28%, confirming the potential for extending survival.

Professors Hye Ryun Kim of the Department of Medical Oncology at Yonsei Cancer Hospital emphasized, “Head and neck cancer has a high recurrence rate, no matter how well surgery and radiation therapy are performed. Major immune checkpoint inhibitors, including Keytruda, can now be used preoperatively, leading to an increase in patients achieving long-term survival. Their greatest strength is their ability to prevent distant metastasis and recurrence.”

"The need for perioperative therapy options is emerging... “Use of Keytruda will increase.”

Head and neck cancer refers to cancers occurring in the oral cavity, pharynx (nasopharynx, oropharynx, hypopharynx), larynx, nasal cavity (sinuses), neck, salivary glands, and thyroid, excluding the brain and eyes. It can develop in over 30 sites in the head and neck region, with tumors originating in the squamous epithelial cells lining mucous membranes—such as the pharynx and salivary glands—accounting for 90% of all cases.

Roughly half of HNSCC patients present with resectable disease, but the complex anatomical structures and vital functions around the face limit the extent of surgery, and achieving adequate resection margins is challenging when major organs are nearby.

The standard treatment regimen, postoperative radiotherapy, has limited efficacy in improving survival, and even after surgery, it is difficult to completely remove microscopic residual disease.

Even in resectable stages, the standard postoperative radiotherapy alone offers limited survival improvement, with 15-50% of patients relapsing within 5 years. Over half of these patients ultimately die, highlighting a substantial unmet need.

This has led to continuous demand for neoadjuvant and adjuvant immunotherapy to reduce the risk of head and neck cancer recurrence. Preoperative adjuvant therapy can reduce tumor size and eliminate micrometastases, facilitating resection. Postoperative adjuvant therapy can remove micrometastases and contribute to preventing recurrence.

Professor Hyun Jun Hong, Department of Otolaryngology at Yonsei Cancer Center, emphasized, “Head and neck cancer surgery can lead to major functional and cosmetic burdens. From an otolaryngology perspective, minimizing recurrence is a priority. When Keytruda was used perioperatively, we saw real benefit. It holds high potential to improve long-term prognosis of patients through synergistic effects with existing treatments.”