I do not have any evidence of what this "treatment" might be, based on the news stories. The name given makes no sense from a scientific view. Furthermore, we have no idea where the parents were intending to take the child, or whom they found to "treat" him.
Several people have speculated about what the "treatment" might be, but there is no evidence that any of the speculations are true. There is also no evidence to link the doctors and hospitals that have spoken up in the news to this case. It seems they are people found by the journalists to say something related to the story.
With all of that said, the only potential treatments that actually do exist and are described in the medical literature are in very early stages, years from human testing. There is no FDA approved treatment and no treatment in clinical trials. The children who have been reported as receiving treatment for a mitochondrial disease in fact have a different disease than Charlie. There is no scientific reason to think their particular treatment would work for the disease that Charlie has.
You must have missed the testimony of the dr who said the treatment had a 10-56% chance of helping Charlie. This dr has agreed to fly from NY to London to evaluate Charlie firsthand.