WESTWOOD, Kan. — New drugs are unleashing the body’s immune system to fight cancer. A new study finds immunotherapy helps some people with advanced melanoma survive at least five years.

It appears that Peg Hardy is getting chemotherapy at K.U. Cancer Center. Far from it. The drip is immunotherapy. The 89-year-old great-grandmother has had no hair loss or nausea.

“I’ve had no reaction. It hasn’t stopped me. I’ve traveled,” said Hardy.

She’s remained active while fighting advanced melanoma, a skin cancer that usually shows up as an irregular mole. In Hardy’s case, melanoma was only found after it got into breast tissue.

The drug, Keytruda, causes her immune system to recognize cancer cells as foreign invaders.

“It trains the immune system to go and kill cancer cells, so it’s a different way to look at cancer treatment,” said Dr. Prakash Neupane, an oncologist at K.U. Cancer Center.

A new study looked at a similar drug, Opdivo. More than a third of advanced melanoma patients on the drug survived at least five years. That’s twice the overall survival rate with advanced melanoma.

“These drugs have a very lasting response when we get a response. That’s why the five-year survival looks really exciting,” said Dr. Neupane.

He cautioned that more research is needed to figure out why many patients don’t respond and what will help them.

Former President Jimmy Carter is among those benefiting from immunotherapy for advanced melanoma. So is Hardy. Four of the five tumors found in her body last summer have disappeared, and the other is shrinking.

“It is a miracle drug. I felt very, very fortunate,” said Hardy.

She’s able to continue her active lifestyle and, perhaps, live longer because of immunotherapy.

The findings on Opdivo were presented at the American Association for Cancer Research meeting.

Dr. Neupane says the same drugs are being used for non-small cell lung cancer and also kidney, bladder and head and neck cancers.