Newswise — SIOUX FALLS, S.D. – A clinical trial at Sanford Health is studying if an immunotherapy drug developed by Merck might be able to treat certain patients with advanced esophageal cancer. The Merck Keynote 181 trial is now open at Sanford.

The study is exploring the Merck drug pembrolizumab, an immune checkpoint inhibitor that allows the body to recognize the cancer and use its immune system to clear the disease. Keynote 181 is open for patients with advanced esophageal cancer who have received two previous therapies. Participants, who must be at least 18, are required to provide a tissue biopsy.

Sanford is also studying the application of pembrolizumab in other types of cancer under the Merck Investigator Studies Program, or MISP. The drug is FDA approved for melanoma and certain types of lung cancer.

Sioux Falls oncologist Jonathan Bleeker, M.D., and Fargo-based oncologist Amit Panwalkar, M.D., are co-principal investigators for the study.

“The immune system plays an important role in regulating the body, but those mechanisms become even more critical when the body needs to fight a disease like cancer,” said Bleeker. “Researchers, including our own at Sanford, have discovered that pembrolizumab can work in treating other types of cancer. Sanford and Merck recognized the need to study the potential of this drug in patients with esophageal cancer.”

Keynote 181 is available in both Sioux Falls and Fargo and is open for 100 participants. For more information or to enroll, call 87-SURVIVAL.

Sanford offers more than 20 clinical trials involving immunotherapy. For a complete list, visit

About Sanford HealthSanford Health is an integrated health system headquartered in the Dakotas. It is one of the largest health systems in the nation with 45 hospitals and nearly 300 clinics in nine states and four countries. Sanford Health’s 28,000 employees, including more than 1,300 physicians, make it the largest employer in the Dakotas. Nearly $1 billion in gifts from philanthropist Denny Sanford have allowed for several initiatives, including global children's clinics, genomic medicine and specialized centers researching cures for type 1 diabetes, breast cancer and other diseases. For more information, visit


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