Charlie's parents, Chris Gard and Connie Yates, have raised £1.3 million (US$ 1.7 million) to take the baby to the USA for nucleoside therapy.
Charlie, who is 11 months old, has infantile onset encephalomyopathic mitochondrial DNA depletion syndrome. He specializes in myopathies and other neuromuscular diseases.
Columbia University medical school specialist Michio Hurano on Monday examined Charlie Gard with British colleagues ahead of a High Court hearing on new experimental treatment and a possible move to the United States for the terminally ill 11-month-old British boy, whose Great Ormond Street doctors are poised to pull the plug after earlier British and European court rulings.
Hirano, who has been providing evidence to the High Court via video link, suggested that now, there is clinical data that were not available in April, and he thought the therapy was "worth trying".
Charlie suffers from the rare genetic condition, which causes progressive muscle weakness and brain damage. He said there was an "11% to 56% chance of clinically meaningful improvement" in muscular function with the proposed treatment.
Court denies bail to actor Dileep
On Friday, a huge crowd had gathered in front of the court premises and booed the actor just like they did on the previous days. The special prosecutor recalled the actor's statements and reactions before his arrest which apparently preyed on the victim.
The court battle continues.
"In my view my keeping Charlie on artificial ventilation will not cause significant harm because he does not seem to be in pain", he said.
Hirano will assess Charlie, meet his current immediate-care team and other specialists, including a doctor from the Vatican children's hospital. After much debate in court on Friday over whether Charlie's parents will be present for this, the Judge announced that Yates will be allowed to attend.
A U.S doctor offering experimental treatment to a critically ill British baby visited the London hospital where he is being treated on Monday as part of a last-ditch attempt to persuade a judge to keep the boy's life support switched on. An individual, who will remain anonymous by court order, will chair the meetings.
"It may be unconventional but this case is full of unconventional aspects", the judge said.