Are you talking about the European trial, referring to “358 patients with SP-MS were allocated placebo and 360 were allocated interferon beta-1b; 57 patients (31 placebo, 26 interferon beta-1b) were lost to follow-up.”?
If so, your interpretation isn’t quite right. It’s not saying they stopped 57 patients short, it’s saying those 57 people didn’t participate at all, but that’s irrelevant to the early ending. The trial stopped short of it’s intended completion time, not short of a number of patients. The blog post indicates it was stopped 2 years early, out of a planned 2-3 year study period.