Trial results for atezolizumab in combination with tiragolumab for the first-line treatment of recurrent/metastatic PD-L1-positive squamous cell carcinoma of the head and neck were posted on ClinicalTrials.gov on 2026-05-05. The combination therapy showed a numerically higher objective response rate of 21.3% compared to 15.4% for atezolizumab plus placebo. Median progression-free survival was 4.14 months versus 2.99 months, and median overall survival was 16.23 months versus 13.57 months, respectively.
Background
Atezolizumab is an immunotherapy approved for various cancers. This study investigated its use in combination with tiragolumab, another investigational immunotherapy, for recurrent/metastatic PD-L1-positive squamous cell carcinoma of the head and neck (SCCHN). SCCHN is a challenging cancer to treat, especially in its recurrent or metastatic forms.
Trial design
The completed Phase 2 trial (NCT04665843) enrolled 123 participants with recurrent/metastatic PD-L1-positive squamous cell carcinoma of the head and neck. The study evaluated atezolizumab plus tiragolumab against atezolizumab plus placebo as first-line treatment. The primary objective was to assess efficacy based on confirmed objective response rate, as determined by the investigator using Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1).
Key results
Key efficacy results from the trial include:
- Objective Response Rate (ORR): The percentage of participants with confirmed objective response was 21.3% in the Tira + Atezo group compared to 15.4% in the Pbo + Atezo group. The Odds Ratio (OR) was 1.57 (95% CI: 0.56, 4.41) with a p-value of 0.3886.
- Duration of Response (DOR): Median DOR was 14.75 months for Tira + Atezo. DOR for Pbo + Atezo was not available.
- Progression-free Survival (PFS): Median PFS was 4.14 months for Tira + Atezo versus 2.99 months for Pbo + Atezo. The Hazard Ratio (HR) was 0.89 (95% CI: 0.58, 1.37) with a p-value of 0.5983.
- Overall Survival (OS): Median OS was 16.23 months for Tira + Atezo versus 13.57 months for Pbo + Atezo. The HR was 0.83 (95% CI: 0.51, 1.35) with a p-value of 0.4457.
- PFS Rate at 6 Months: The rate was 42.10% for Tira + Atezo versus 35.90% for Pbo + Atezo. The difference in event-free rate was 6.2% (95% CI: -12.46, 24.86) with a p-value of 0.515.
- OS Rate at 6 Months: The rate was 83.37% for Tira + Atezo versus 76.92% for Pbo + Atezo. The difference in event-free rate was 6.45% (95% CI: -9.14, 22.04) with a p-value of 0.4176.
- OS Rate at 12 Months: The difference in event-free rate was 11.79% (95% CI: -7.32, 30.91) with a p-value of 0.2266.
What this means
The results indicate that the combination of atezolizumab and tiragolumab numerically improved objective response rate, progression-free survival, and overall survival compared to atezolizumab plus placebo in this Phase 2 study. While these numerical improvements were observed, the statistical analyses for objective response rate, progression-free survival, and overall survival did not reach statistical significance (p-values > 0.05). These findings suggest a potential signal of activity for the combination, warranting further investigation in larger clinical trials to determine its definitive efficacy and role in the treatment of recurrent/metastatic PD-L1-positive squamous cell carcinoma of the head and neck.
Source
The information for these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04665843, titled 'A Study of Atezolizumab Plus Tiragolumab and Atezolizumab Plus Placebo as First-Line Treatment in Participants With Recurrent/Metastatic PD-L1 Positive Squamous Cell Carcinoma of the Head and Neck,' were posted on 2026-05-05 on clinicaltrials.gov.