Trial results for a Phase 2 study evaluating adjuvant pembrolizumab in high-risk head and neck cancers were posted on ClinicalTrials.gov on 2026-05-13. The study, known as the PATHWay Study, showed that pembrolizumab improved progression-free survival (PFS) to 49.7% compared to 35.3% for placebo.
Background
The PATHWay Study investigated pembrolizumab as an adjuvant treatment for patients with squamous cell carcinoma of the head and neck who were at high risk for recurrence. The trial aimed to assess if one year of adjuvant pembrolizumab could improve progression-free survival in this specific patient population.
Trial design
The randomized, double-blind Phase 2 PATHWay Study (NCT02841748) enrolled 100 participants with head and neck cancer, specifically squamous cell carcinoma of the head and neck, who were at high risk for recurrence. The study compared adjuvant pembrolizumab against placebo, with the primary objective of improving progression-free survival.
Key results
The trial results showed the following for progression-free survival (PFS):
- Overall, 49.7 percentage of participants in the pembrolizumab group achieved PFS, compared to 35.3 percentage of participants in the placebo group.
- An analysis using the Log Rank method reported a Hazard Ratio (HR) of 0.7 (80% Confidence Interval: 0.5 to 0.98) with a p-value of 0.067, favoring pembrolizumab.
- In patients with PD-L1 >=10% positive status, 57.1 percentage of participants in the pembrolizumab group achieved PFS, compared to 40.9 percentage of participants in the placebo group.
For overall survival (OS), the results were:
- Overall, 82.8 percentage of participants in the pembrolizumab group achieved OS, compared to 82.0 percentage of participants in the placebo group.
- An analysis using the Log Rank method reported a Hazard Ratio (HR) of 0.94 (80% Confidence Interval: 0.53 to 1.69) with a p-value of 0.34.
- In patients with PD-L1 >=10% positive status, 85.7 percentage of participants in the pembrolizumab group achieved OS, compared to 95.4 percentage of participants in the placebo group.
- An analysis using the Log Rank method reported a Hazard Ratio (HR) of 2.54 (80% Confidence Interval: 0.95 to 6.77) with a p-value of 0.14 for OS in PD-L1 >=10% positive patients.
What this means
The results from the Phase 2 PATHWay Study indicate a numerical improvement in progression-free survival for patients with high-risk head and neck cancer receiving adjuvant pembrolizumab compared to placebo. While the p-value of 0.067 for the overall PFS analysis did not meet a conventional threshold for statistical significance, the Hazard Ratio of 0.7 suggests a potential reduction in the risk of progression or death. The benefit in PFS was also observed in the PD-L1 >=10% positive subgroup. However, overall survival rates were very similar between the two groups, and in the PD-L1 >=10% positive subgroup, the placebo arm showed a higher overall survival rate. These findings suggest a potential role for pembrolizumab in improving PFS in this high-risk population, warranting further investigation in larger studies.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for the study NCT02841748, titled "A Randomized, Double-Blind Phase II Study of Adjuvant Pembrolizumab Versus Placebo in Head and Neck Cancers at High Risk for Recurrence- the PATHWay Study", were posted on 2026-05-13 on clinicaltrials.gov.