which is what it must be? >> that's part of the frustration, that it is ongoing and tedious. and you don't know from one day to the next what you're going to get. and there are exacerbations. a couple months ago, richard was in a bad place. and i think we were both very low about it and depressed. and then he had a steroid treatment, and came back to where he had been prior to that. but you never know whether those are going to work. or we're going to see yet another -- problem developing. >> you have to learn to live with ambiguity. >> but this could be, meredith, a hugely significant moment in the treatment of ms. >> absolutely. >> if in a year's time we're back here doing another interview and you've made significant progress suddenly, this could be the one breakthrough everyone has been waiting for. because 3 to 500,000 people in america have a form of ms. >> and when you have secondary progressive like richard, as he said, there is nothing out there. so this would be huge for people in that position.