If you have a lot of it, beware. A significant portion of people hate italics, and a book stuffed full of them in place of non-intrusive punctuation will be a no-go for them. I would likely be one of those people. Italics are much more difficult to read and disrupt my immersion unless used sparingly.
Some other authors have used alternate punctuation for telepathy (as well as normal quote marks). _hello_ :hello: <hello> «hello» That last one is actually normal quote marks in some languages; they're called angle quotes. Also, personally, I have no problem with quotes once telepathy is established. I don't need beat over the head with the fact they are telepathic, I just want to read the story. John sent, "Hello." is clearly not speech, and I'm sure you could come with a couple more verbs.