Fraud has other components beyond just lying. For example, I could tell you that I'm Santa Claus, and, due to the rising complexity of children's toys, I need more money to hire additional elves this year, would you please donate?
That wouldn't be fraud though, because, among other things, you aren't damaged by it. You might be damaged by it if you sent me your money, and I actually used it to buy myself sugar cookies, but you didn't.
What I'm trying to get at is "harm" or "damage" is typically a component of a fraud case. In this case, the defense of "My investors didn't lose money, but actually made back multiples of their initial investment" seems very strong to me.
Shkreli had a company which failed and lost investors money. Rather than break the bad news, he lied to them, started another company, made more money, and paid back his investors. I may have the details wrong, but from this article, that was my main takeaway.
The point about damage goes to intent. Did Shkreli lie to people to take their money and make himself rich? Or did he lie to people to get a working productive business and pay off his investors? The fact that he did the latter implies his intent was the latter.
If I were an investor, I'd be upset that the initial investment failed. I'd be litigious if I realized he had lied to me. If he lied to me and returned my money with profit, I'd just stop doing business with him in the future.