Trial results for a Phase 2 study (NCT04454489) investigating pembrolizumab in combination with quad-shot palliative radiotherapy for advanced head and neck squamous cell carcinoma were posted on ClinicalTrials.gov on 2025-11-19. The single-arm study reported an overall response rate of 40.0% in participants receiving the combination therapy.
Background
The study investigated pembrolizumab in combination with quad-shot palliative radiotherapy for various forms of head and neck squamous cell carcinoma, including advanced, recurrent, metastatic, Stage III cutaneous, and locally advanced presentations.
Trial design
The Phase 2 study (NCT04454489) was a single-arm, non-randomized pilot study that enrolled 21 participants. It evaluated the efficacy and tolerability of combination quad-shot palliative radiotherapy with pembrolizumab for advanced, recurrent, or metastatic head and neck cancer. The conditions studied included Advanced Head and Neck Squamous Cell Carcinoma, Recurrent Head and Neck Squamous Cell Carcinoma, Metastatic Head-and-neck Squamous-cell Carcinoma, Stage III Cutaneous Squamous Cell Carcinoma of the Head and Neck, and Locally Advanced Head and Neck Squamous Cell Carcinoma.
Key results
The trial results for the combination of quad-shot palliative radiotherapy and pembrolizumab reported the following outcomes:
- The Overall Response was 40.0 percentage of participants.
- The Response Rate in the Target Lesions was 40.0 percentage of evaluable patients.
- The Response Rate in the Non-Target Lesions was 10 percentage of evaluable patients.
- The mean Duration of Response at the Target Lesions was 11.6 months.
- The median Duration of Response at the Target Lesions was 9.44 months.
- The median Progression-Free Survival was 9.2 months.
- The median Overall Survival was 14.9 months.
- Adverse Events, assessed using PRO-CTCAE Version 5.0, were reported in 7 percentage of evaluable patients.
What this means
The findings from this Phase 2 pilot study suggest that the combination of quad-shot palliative radiotherapy with pembrolizumab may offer a meaningful overall response and disease control in patients with advanced, recurrent, or metastatic head and neck squamous cell carcinoma. The observed median progression-free survival of 9.2 months and overall survival of 14.9 months, alongside a 40.0% overall response rate, indicate potential clinical benefit. The tolerability profile, with 7% of evaluable patients experiencing adverse events as assessed by PRO-CTCAE, provides initial insights into the safety of this combination therapy in this patient population.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04454489, titled "Quad Shot Radiotherapy in Combination With Immune Checkpoint Inhibition," were posted on 2025-11-19 on clinicaltrials.gov.