Nivolumab was clinically active and well-tolerated among patients with treatment-refractory metastatic squamous cell carcinoma of the anal canal (SCCA), according to a study published in The Lancet Oncology.1
Intratumoral human papillomavirus oncoproteins upregulate immune checkpoint proteins to evade tumor-infiltrating lymphocytes. For this study, researchers evaluated the efficacy and tolerability of nivolumab, an anti-PD-1 antibody, in patients with metastatic SCCA.
For the multicenter, single-arm, phase 2 trial (ClinicalTrials.gov Identifier: NCT02314169), investigators enrolled 37 patients with metastatic SCCA who were treated with at least 1 prior systemic treatment for incurable, advanced, or metastatic SCCA. Of those, 86% received a platinum-based regimen for metastatic disease and 84% previously received radiation to the primary tumor.
At a median follow-up of 10.1 months, 24% (95% CI, 15-33) of patients achieved a response, including 2 complete responses and 7 partial responses. Investigators observed durable responses in 78% of responding patients, with a median duration of response of 5.8 months.
Median progression-free survival was 4.1 months (95% CI, 3.0-7.9); 38% (95% CI, 24-60) of patients were progression-free at 6 months. Median overall survival was 11.5 months (95% CI, 7.1-not estimable). Investigators estimated that 48% (95% CI, 32-74) of patients would be alive at 1 year.
The most common adverse events were anemia, fatigue, and rash. Five patients had grade 3 adverse events, including anemia in 2 patients and fatigue, rash, and hypothyroidism each in 1 patient.
These findings suggest that PD-1 blockade with nivolumab may be an effective and safe strategy in this patient population.
- Morris VK, Salem ME, Nimeiri H, et al. Nivolumab for previously treated unresectable metastatic anal cancer (NCI9673): a multicentre, single-arm, phase 2 study. Lancet Oncol. doi: 10.1016/S1470-2045(17)30104-3 [Epub ahead of print]