"A rare malignancy known as squamous cell carcinoma of the anal canal SCCA is on the increase and now researchers have reported results of the firstever phase II clinical trial results for treatment with the immunotherapy drug nivolumab. The phase II study for which findings are being presented at this weeks American Association for Cancer Researchs annual meeting in New Orleans was designed and led by researchers at The University of Texas MD Anderson Cancer Centers Human PapillomavirusRelated HPV Cancers Moon Shot Program. MD Anderson enrolled  patients who volunteered to provide both pre and posttreatment tissue samples. The study revealed encouraging correlations between immunologic biomarkers and responses to treatment. There have been no standardized treatment options for metastatic SCCA patients said Van Morris M.D. assistant professor of Gastrointestinal Medical Oncology. This study demonstrated responses in five of  patients treated at MD Anderson and many of the patients had significant reductions in their tumor size. In this first prospective phase II trial for refractory metastatic SCCA our exploratory analysis of pre and ontreatment tissues samples revealed potential correlations between immunologic biomarkers and clinical outcomes to nivolumab said Cathy Eng M.D. professor of Gastrointestinal Medical Oncology and national study principal investigator. Metastatic SCCA a cancer often associated with human papillomavirus HPV infection is normally treated with chemotherapy although no trials have established a standard of care. The study employed the monoclonal antibody nivolumab one of the drugs represented among the growing arsenal of immunotherapy therapies. The drug frees the immune system to attack cancer by disrupting a brake that halts immune response. This the first formal clinical trial completed with patients with previously treated metastatic SCCA said Morris. In this trial patients received a biopsy just before being treated with nivolumab and then a second paired biopsy after two doses. Study results showed a decrease in frequency of CD Tcells in posttreatment tumor samples among responderpatients. Immune monitoring of pretreatment samples showed a significantly higher percentage of CD and CD Tcells as well as other indicators all which point to correlations between immunologic biomarkers and responses to treatment. Five other markers did not demonstrate significant differences. Of note patients who scored as responders had higher frequency of CD Tcells and PDL CD immune cells in pretreatment samples.  The study was funded by MD Andersons HPV Moon Shots Program and the HPV Anal Cancer Foundation the E.B. Anal Cancer Fund and a philanthropic donation. The Moon Shots Program aims to accelerate the conversion of scientific discoveries into clinical advances and significantly reduce cancer deaths. Study team members for the correlative analysis included Armeen Mahvash M.D. Interventional Radiology Luis Vence Ph.D. Jorge Blando D.V.M. and James Allison Ph.D. all of Immunology Robert Wolff Cancer Medicine Aki Ohinata GI Medical Oncology Chimela Ohaji Investigational Cancer Therapeutics and Padmanee Sharma M.D. Ph.D. Genitourinary Medical Oncology. Final clinical results for the study will be reported at the American Society of Clinical Oncologys  annual meeting in Chicago by Eng on behalf of the National Cancer Institutes Experimental Therapeutics Clinical Trials Network ETCTN and its collaborators."