KANSAS CITY, Mo. -- An eight-year-old boy from Madison, Kan. has stage-four cancer. His latest treatment is part of a revolution in cancer therapy -- using the immune system to attack the disease.
When FOX 4 first shared Braysen Butter's story last November, he was getting an infusion of an experimental cancer drug.
"I do TPI. There's a secret number to do it and it's 15," Braysen said about the infusion rate.
TPI-287 was Braysen's secret weapon against neuroblastoma, a nerve cell cancer that had spread to his spine. His tumors disappeared.
Fast forward to July. Braysen threw out the first pitch at the celebrity game at Kauffman Stadium.
"Awesome," he said of the experience.
But the news the family received just weeks before wasn't.
"We were very devastated. We didn't know..." said Jess Butter, Braysen's mother.
The cancer was back. This time, it was in Braysen's pancreas. Dr. Doug Myers of Children's Mercy Hospital proposed a different attack that many believe is the future of cancer medicine.
"Going right after the tumor. Leaving other cells in the body alone, so decreasing toxicity and then only giving things that target that patient's tumor," said Dr. Myers.
The therapy uses the immune system to target the tumor. It's a two-pronged approach in Braysen's case that was designed by Dr. Myers and only being used at Children's Mercy.
In September, Braysen received a bone marrow transplant from his mom that had a vacuum created in it. T cells, which are immune cells, had been removed.
Then in October, he received a shot of T cells from his mom.
"Into that vacuum or that space, and hopefully that encourages those tumor-fighting cells to expand before the rest of the immune system comes back and kinda fills the space, so to speak," said Dr. Myers.
The T cells had a gene added to target Braysen's tumor. This week, Dr. Myers had news for the Butters. The tumor appears to be shrinking.
"It's hard to believe it's not significantly better," he told the family.
Braysen's mother said she has lots of hope.
"They're not giving up, and we're not giving up, so we're looking forward to more time," she said.
Braysen will likely get another shot of T cells on Monday.
One other child has had the therapy at Children's Mercy. Dr. Myers said it helped for six months before the tumor returned. He said the child had more tumor at the start than Braysen had, so the hope is for a better result.