Trial results for a Phase 2 study (NCT03799445) investigating nivolumab, ipilimumab, and radiation therapy in patients with HPV positive advanced oropharyngeal squamous cell carcinoma were posted on ClinicalTrials.gov on 2026-03-17. The study reported a mean pathologic response with -67.3% change in viable tumor.
Background
The trial investigated the combination of ipilimumab, nivolumab, and radiation therapy for treating patients with advanced human papillomavirus (HPV) positive oropharyngeal squamous cell carcinoma. Ipilimumab and nivolumab are monoclonal antibodies that function as immunotherapies, aiming to stimulate the body's immune system to target cancer cells. Radiation therapy uses high-energy x-rays to reduce tumor size and eliminate cancer cells.
Trial design
The Phase 2 study (NCT03799445) was designed to evaluate the combination of ipilimumab, nivolumab, and radiation therapy. It enrolled 37 participants with conditions including Clinical Stage I HPV-Mediated (p16-Positive) Oropharyngeal Carcinoma AJCC v8, Clinical Stage II HPV-Mediated (p16-Positive) Oropharyngeal Carcinoma AJCC v8, Human Papillomavirus Positive Oropharyngeal Squamous Cell Carcinoma, Oropharyngeal Basaloid Carcinoma, and Pathologic Stage I HPV-Mediated (p16-Positive) Oropharyngeal Carcinoma AJCC v8. The trial was terminated.
Key results
The trial reported results for radiographic response, pathologic response, and toxicity in the experimental group receiving ipilimumab, nivolumab, and radiation therapy.
- For "Radiographic (RECIST) Response," 5 participants showed a response, 29 participants showed no response, and 1 participant had progressive disease.
- For "Pathologic Response -- Percent Viable Tumor Change," the mean change was -67.3% (Standard Deviation: 28.3) in viable tumor.
- Regarding "Toxicity (Number of Adverse Events)," the reported counts were 0, 0, 3, 0, 0, 19, 11, and 16 events across different categories.
What this means
The results from this Phase 2 study indicate that the combination of nivolumab, ipilimumab, and radiation therapy led to a substantial mean reduction in viable tumor of -67.3% in patients with HPV positive advanced oropharyngeal squamous cell carcinoma. While 5 participants showed a radiographic response, the majority did not, suggesting varied individual responses. The reported toxicity events provide initial safety data for this combination in this patient population, though further context on the severity and nature of these events would be necessary for a full safety profile assessment.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT03799445, titled "Ipilimumab, Nivolumab, and Radiation Therapy in Treating Patients With HPV Positive Advanced Oropharyngeal Squamous Cell Carcinoma," were posted on 2026-03-17 on clinicaltrials.gov.