Adrienne Skinner awoke from cancer surgery to stunning news. “I came to, and he told me we couldn’t do it. ”Skinner says of her surgeon, who had planned to remove a tumor from the end of her bile duct. He said cancer has invaded your liver, it’s stage 4. Its systemic. She was diagnosed with ampullary cancer, a form so rare that no standard treatments existed. Until now.

After some pretty nasty chemotherapy, skinner, 60, of New York became part of a clinical trail for pembroli-zumab, marketed by Merck as Keytruda. The drug helps the body immune system fight the disease.

Skinner started infusion treatments in April 2014. In July her surgeon took another biopsy. “he said, ‘If somebody hadn’t told me you had cancer, I would never have known’” she notes. The tumor was gone.

The FDA has since approved further uses of Keytruda, such as for patients with a genetic mutation called mismatch repair deficiency. The drug continues to be tested for use by patients without mutation. It is approved for some head and neck, lung, bladder and metastatic melanoma cancers as well as Hodgkin lymphoma.

During clinical trials, the medication was famously used to treat former President Jimmy Carter, who two years ago announced he had cancer in his brain and liver and said his fate was “in the hands of God, whom I worship”. Four months later, his cancer was gone.

Skinner has seen similar results. She’s back at work and makes a point of swimming and playing tennis. “I’m running around like a maniac. I’m out gardening right now” she says. “I know what a gift is and I know the gift of life”