Interesting, page-5173

Officially they have to nominate a number in the app,ovation and that's what you see there.
Previous company announcements have mentioned 20-30 and also 15-30.
They can call it a day anytime they want with the risk being that stage 2 trials with much larger numbers needed will be harder with a successful first trial of only a handful.
The phase2 trials will almost certainly be done in the US and with over 300 million people it should be a much simpler task.
I hope we can get at least 15-20, with the number of sites we'll have soon it's really hard to see that not happening.