Acadia Pharmaceuticals will be conducting DAFFODILTM, a clinical study of trofinetide in approximately 10 girls with diagnosed Rett syndrome, aged 2 to 5 years. DAFFODIL will be a 12-week, multicenter, open-label safety, tolerability and pharmacokinetics study in this younger age group, followed by a possible open-label extension for up to an additional 21 months.