Eseba-vec Plus Pembrolizumab Shows Promise in HPV16-Positive Head and Neck Cancer

Key Insights

• A phase II trial evaluated eseba-vec, an HPV16-targeted immunotherapeutic agent, combined with pembrolizumab as a first-line treatment for HPV16-positive relapsed or metastatic head and neck squamous cell carcinoma.
• The combination therapy demonstrated an overall response rate of 52% in patients with PD-L1 CPS ≥ 20, with a disease control rate of 80% as of the September 2024 data cutoff.
• Preliminary median progression-free survival exceeded 16 months, and the 12-month overall survival rate was 83%, with 66.7% of confirmed responses ongoing.

A novel combination of eseba-vec and pembrolizumab is showing promising results in patients with HPV16-positive relapsed or metastatic head and neck squamous cell carcinoma. The phase II trial results, presented at the 2024 Society for Immunotherapy in Cancer (SITC) Annual Meeting, indicate a clinically meaningful response rate and encouraging progression-free and overall survival data.

The study focused on a subset of 27 patients with PD-L1 combined positive score (CPS) ≥ 20, with 25 patients evaluable for response. The data revealed an overall response rate of 52% for all eseba-vec doses tested, and a disease control rate of 80%, as of the September 2024 data cutoff. Preliminary median progression-free survival is more than 16 months, with a 12-month overall survival rate of 83%. Furthermore, 66.7% of confirmed responses are ongoing.

Durable T-Cell Response

Investigators reported that the observed clinical activity is supported by a rapid and durable tumor antigen–specific T-cell response. Data are generally consistent for the selected phase III dose level, including a 55% overall response rate, which is an approximately twofold increase compared with historical pembrolizumab monotherapy data. Serious treatment-related adverse events occurred in 7.6% of patients.

Expert Commentary

"As a medical oncologist who specializes in head and neck cancers, I am inspired by the results of the expanded eseba-vec/pembrolizumab phase II study because of the potentially clinically meaningful response rate and encouraging [progression-free survival and overall survival] data," said Alan Ho, MD, PhD, Chief of the Head and Neck Oncology Service at Memorial Sloan Kettering Cancer Center. "In addition, the regimen has a manageable safety profile that ensures most patients can maintain treatment."

The study suggests that the combination of eseba-vec and pembrolizumab could offer a significant improvement in outcomes for patients with HPV16-positive relapsed or metastatic head and neck squamous cell carcinoma, particularly those with high PD-L1 expression.