That was the study without a control; for the placebo controlled study, they don't give the numbers, just say "statistically significant improvements" on several metrics.

(Without a control group, you have questions about how people of that age generally progress, and what other treatment/therapies they receive over those 2 years. The phase 1 trial was with children whose parents presumably sought ever possible way to help them, while the placebo controlled phase 2 was adults who may have plateaued.)