In a single-center phase II trial reported in the Journal of Clinical Oncology, McBride et al found that use of stereotactic body radiotherapy (SBRT) for a potential abscopal effect together with nivolumab did not improve objective response rate vs nivolumab alone in patients with metastatic head and neck squamous cell carcinoma.
Study Details
In the open-label trial, 62 patients at Memorial Sloan Kettering Cancer Center were randomly assigned between March 2016 and June 2018 to receive nivolumab at 3 mg/kg every 2 weeks with (n = 32) or without (n = 30) SBRT at 9 Gy x 3 to 1 lesion. Patients had at least two metastatic lesions, including one that could be safely irradiated and one measurable by Response Evaluation Criteria in Solid Tumors version 1.1. The primary endpoint was objective response rate in nonirradiated lesions.
Treatment Outcomes
Objective response rates in nonirradiated lesions were 34.5% in the nivolumab group vs 29.0% in the nivolumab plus SBRT group (P = .86). Median duration of response was not reached (95% confidence interval [CI] = 10.7 months–not reached) in the nivolumab group vs 9.4 months (95% CI = 9.3 months–not reached) in the nivolumab plus SBRT group. There was no significant interaction between treatment group and PD-L1 status (P =.76). Among 56 patients with known PD-L1 status, objective response rates were 50.0% in patients with PD-L1–positive tumors (tumor proportion score ≥ 1%) vs 23.5% in those with PD-L1–negative tumors (P = .08).
KEY POINTS
- The addition of SBRT to nivolumab did not improve objective response rate in nonirradiated lesions.
- No differences in progression-free or overall survival were observed.
Median follow-up in surviving patients was 20.2 months. Median progression-free survival was 1.9 months (95% CI = 1.8–16.7 months) in the nivolumab group vs 2.6 months (95% CI = 2.1–9.2 months) in the nivolumab plus SBRT group (P = .79). Median overall survival was 14.2 months (95% CI = 8.15 months–not reached) vs 13.9 months (95% CI = 7.79 months–not reached; P = .75).
Toxicity
Adverse events of any grade occurred in 70% of patients in the nivolumab group vs 87.1% of the nivolumab plus SBRT group (P = .12). Grade ≥ 3 adverse events occurred in 13.3% vs 9.7% (P = .70).
The investigators concluded, “We found no improvement in response and no evidence of an abscopal effect with the addition of SBRT to nivolumab in unselected patients with metastatic head and neck squamous cell carcinoma.”
Nancy Lee, MD, of Memorial Sloan Kettering Cancer Center, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported in part by a grant from the National Cancer Institute. For full disclosures of the study authors, visit ascopubs.org.
