Moderna Therapeutics, the drug company that has become a domestic leading contender in the race for a vaccine, has also attracted unwanted attention for its executive trading. The company's stock shares rose as much as 21% in April after the company announced a deal with the federal government that would pay as much as $483 million for the development of a vaccine. Executive trading activity ahead of Moderna announcements about the promise of its vaccine candidate drew scrutiny, even as the company explained that its executives who had traded had followed SEC guidelines by filing documents laying out a schedule of stock sales in advance -- to avoid any potential suspicion that they were trading based on inside information.