one word for 'by leaps and bounds'
Welcome to the forum, rrbbmc.
A more meaningful title for this thread would be "Leaps and bounds."
As for your question, some context would be helpful. If you wanted to say that "he grew by leaps and bounds," you could substitute "rapidly."
"Skyrocket" is another. As in "Under my cap and trade system, electricity prices will necessarily skyrocket."