After she had receiving confirmation Flory's fortnightly treatment would continue, Phoebe said: "Families will see our children living longer with a better quality of life, while being completely hopeless."
She said getting the drug on the NHS had been "absolutely monumental" for Flory, and she believed her daughter was still walking, climbing and eating thanks to it.
"To know that she's going to have access to this indefinitely… is everything," she said.
"This treatment completely changes the trajectory of her life. Before, her entire life was uncertain."
But while it is a massive relief for her family, she is determined to keep advocating for others.
Phoebe urged decision makers to do the right thing, adding they were "halfway there".
"Every child should be able to access this treatment," she said.
"It is is life-changing. To offer it some and not others seems brutally unfair."
NICE said it would keep working with NHSE and BioMarin towards a long-term deal for all patients after a managed access agreement ended in December.
"We know this is not entirely the news people in the Batten Disease community were hoping for," said NICE director of medicines evaluation Helen Knight.
"However, this is not the end of the story. We will continue to work with all parties towards a solution."
The Batten Disease Family Association said it was pleased with the agreement, but would continue to push for Brineura to be accessible for all children.
