Treatment to help a five-year-old football mascot with cancer "is not working", his heartbroken family have announced.
A post on Bradley Lowery's Facebook support page said hospital tests had revealed that a "last option" treatment was unsuccessful.
The post read: "We have just got back from the hospital with news no parent should ever have to hear.
"Scan results show treatment that Bradley has been receiving is not working.
"This means we will not get him cancer free as this was our last option."
The family said Bradley would take part in a trial in London, but the treatment had no previous success for their son's type of cancer.
"We are understandably heartbroken about the recent news - hearing this type of thing never gets easier," the family said.
"We don't know how long it will be before the cancer wins, but what we do know is that we will continue to make memories and enjoy our superhero every second of the day.
"Thank you to everyone for all your support."
Bradley, from Blackhall, was diagnosed with cancer when he was 18 months old and went into remission two years later.
But in July 2016 he relapsed, and his family raised thousands of pounds for specialist treatment in the US.
His battle with cancer has hit the headlines around the world after appearances with his football heroes in hospital and at matches.
He appeared as a mascot for Sunderland and Everton and was selected to lead England out in their World Cup qualifier against Lithuania.
Earlier this season Everton shocked his family by pledging £200,000 towards his ground-breaking treatment in America.
And he was visited at a Newcastle hospital by Sunderland players and fell asleep in the arms of star striker Jermain Defoe.