The first-ever phase 2 clinical trial results are promising for the use of nivolumab to treat squamous cell carcinoma of the anal canal (SCCA).1 The results were presented at American Association for Cancer Research Annual Meeting, held April 16-20, 2016, in New Orleans, Louisiana.
The phase 2 trial was conducted as part of the human papillomavirus (HPV)-related cancers Moon Shot Program at The University of Texas MD Anderson Cancer Center. A total of 18 patients volunteered to provide both pre- and post-treatment tissue samples, and these samples were used to find encouraging correlations between immunologic biomarkers and responses to treatment.
“There have been no standardized treatment options for metastatic SCCA patients,” said Van Morris, MD, assistant professor of Gastrointestinal Medical Oncology. “This study demonstrated responses in 5 of 18 patients treated at MD Anderson, and many of the patients had significant reductions in their tumor size.”
“In this first prospective phase 2 trial for refractory metastatic SCCA, our exploratory analysis of pre- and on-treatment tissues samples revealed potential correlations between immunologic biomarkers and clinical outcomes to nivolumab,” said Cathy Eng, MD, professor of Gastrointestinal Medical Oncology at MD Anderson and national study principal investigator.
Normally metastatic SCCA is treated with chemotherapy, though no clinical trials have established a standard of care. SCCA is often associated with infection with HPV.
Nivolumab, which this study used, is one of a growing number of immunotherapy drugs. The drug frees the immune system to attack cancer by disrupting a brake that halts immune response.
“This is the first formal clinical trial completed with patients with previously treated metastatic SCCA,” said Dr Morris. “In this trial, patients received a biopsy just before being treated with nivolumab and then a second paired biopsy after 2 doses.”
Among patients who responded to the nivolumab treatment, a decrease in the frequency of CD8 T-cells occurred. Also, these responder patients had pretreatment samples with a significantly higher percentage of CD3 and CD8 T cells, along with other indicators. These all point to correlations between immunologic biomarkers and responses to treatment.
Of note, patients who scored as responders had higher frequency of CD8 T-cells and PD-L1 CD45 immune cells in pretreatment samples.
1. First-ever nivolumab study to treat aggressive anal cancer appears promising [news release]. Houston, TX: University of Texas MD Anderson; April 15, 2016. https://www.mdanderson.org/newsroom/2016/04/first-ever-nivolumab.html. Accessed April 28, 2016.