The final analysis of the HN9 trial shows that new immunotherapy treatment did not improve event free survival

Final results from the CCTG HN.9 (EORTC 1740-HNCG) were presented at ASCO 2026, highlighting the challenges of reducing treatment intensity while maintaining outcomes for patients with human papillomavirus (HPV)-positive oropharyngeal cancer. The study evaluated a cisplatin-free treatment approach combining immunotherapy (durvalumab) with radiation therapy in patients with intermediate-risk, HPV-positive, locally advanced oropharyngeal squamous cell carcinoma. Researchers investigated whether replacing the standard chemotherapy drug cisplatin with immunotherapy could reduce severe long-term side effects while maintaining the same event free survival benefit.

“HN9 was a unique and innovative study that looked at a novel approach of treatment de-escalation in HPV positive head and neck cancer replacing cytotoxic chemotherapy with immunotherapy, a significant contribution to our knowledge of the integration of immunotherapy in the primary management of head and neck cancer," says study co-chair Dr. Khalil Sultanem, Radiation Oncologist at Jewish General Hospital. 

The study found that the chemotherapy-sparing combination did not improve event-free survival compared to standard treatment. No new safety signals were identified. While specific toxicities differed between treatment arms, overall quality-of-life outcomes — including swallowing function — were similar between groups and consistent with findings from previous trials.

Researchers noted that future treatment de-escalation strategies must carefully balance efficacy, toxicity, and patient-reported outcomes. Biomarker analyses are ongoing to identify whether certain subgroups of patients may benefit from this approach and to better predict treatment responsiveness.

"Academically led trials like HN.9 are essential to define not only whether new therapies work, but for whom they work,” study co-chair Dr. Anna Spreafico, Princess Margaret, University Health Network who presented the results. “By integrating detailed clinical, quality-of-life, and biomarker analyses, this study provides a foundation for more precise patient selection in future trials.”