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 ( 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.

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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.

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These findings suggest that PD-1 blockade with nivolumab may be an effective and safe strategy in this patient population.


  1. 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]