The final 25,000 pounds required for the treatment was donated by the Championship side's (second tier) Spanish midfielder Samuel Saiz this week.
"We talk about family and togetherness a lot at our club, it's a culture we have been determined to reinstate across everyone involved with Leeds and raising this money has truly been a team effort," Leeds managing director Angus Kinnear said.
"Staff, players, corporate partners and our supporters have united together to give Toby the best opportunity with further treatment and I am incredibly proud of everyone concerned."
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The club have invited Toby to attend Saturday's game with Millwall at Elland Road.
Sunderland fan Bradley Lowery, who died aged six last July, also suffered from the rare form of cancer which spreads rapidly across the body. He became known nationally as he accompanied the team in taking to the pitch before matches.
He was often in the arms of England international striker Jermain Defoe, who described the child as his best friend.
(Reporting by Shrivathsa Sridhar in Bengaluru, editing by Pritha Sarkar)
