Yes. PI's are optimistic about the work they do, and are often misquoted by journalists optimistic about the subjects they report on. And investors are optimistic about the companies they invest in. It's all very natural, and you just have to be aware of the bias and keep your perspective and context. This means "Would they extend the trial if it didn't work????" is a foolish question. The blunt answer is: yes, they would. And not because they are fools or because this is a scam. It's because medicine is tricky.