There's no defense against someone who can claim to have illegal advance knowledge of clinical trial results, tweets a lie that it failed, kills the stock and then, when at least a dozen shareholders reported this obvious violation of securities laws to the SEC, the SEC not only declined to investigate but did not even acknowledge receipt of the complaint from most of us -- as the law states they have to do.
So, if you are Martha Stewart and someone tells you to sell $74k worth of stock, and you do it, you go to the slammer. If you are Feuerstein and destroy a company, and the investment of small investors, you don't even get investigated.
By the way, he deleted the tweet, so don't expect to find it if you are able to go back and look at tweets from years ago.