(CBS News) PHILIPSBURG, Penn. - An experimental cancer treatment that generated a lot of excitement last year when it was shown to work in adults, is showing equal promise in children.
The treatment uses a patient's own immune cells to kill cancer. It's being tested now in 12 patients with advanced leukemia: 10 adults, and two children. Researchers say nine of the patients have responded to the therapy, including both pediatric patients.
Two years ago, Emily Whitehead was just five when her mother, Kari, felt something was wrong.
"I noticed one evening when I was giving her a bath that she had a lot of black and blue marks all over her body," Kari said.
Emily had "ALL," acute lymphoblastic leukemia. It's curable in 85 percent of children who undergo chemotherapy.
But for Emily, chemo didn't work. She thinks her dog Lucy knew it first when her cancer came back.
"She wouldn't like play with me or anything. She would just sit," Emily said.
Emily was too sick for more chemo, so her family turned to an experimental therapy at the Children's Hospital of Philadelphia.
"This is a whole new way of treating cancer, and the idea is that we're redirecting the cells of the immune system against the cancer," said Dr. Stephan Grupp, who is leading the study.
Scientists use the patient's own immune cells called "T-cells" - white blood cells that help fight infections. Scientists remove the T-cells, genetically engineer them to attack leukemia cells, and inject them back into the patient.
"The cells actually grow within the patient and can attack a large amount of cancer cells," Grupp said.
Emily received an infusion of her engineered T-cells last April. She suffered life-threatening complications. Her father, Tom, remembers it clearly.
"They took us out in the hall and said there is no room to get sicker. She is as sick as she can get. You should call your family in. There's a good chance she won't be here in the morning," Tom said.
Doctors managed the toxic effect, and 10 days later, she showed dramatic improvement.
"We can't find any leukemia in her body, using the most sensitive tests we have," Grupp said.
Emily has been cancer-free for eight months. If it doesn't come back for two years, her doctors can declare her cured.