FDA
New trofinetide formulation OK’d for Rett syndrome
Brand name: Daybue Stix
Generic name: trofinetide
Manufacturer: Acadia Pharmaceuticals
Approval date: December 12, 2025
FDA has approved Daybue Stix (trofinetide) for oral solution, a dye- and preservative-free powder formulation of trofinetide for the treatment of Rett syndrome in adult and pediatric patients ≥2 years of age.
According to the manufacturer, the new formulation is expected to deliver the same efficacy and safety profile of Daybue oral solution, while offering individuals with Rett syndrome new flexibility and choice regarding dose volume and taste.
Efficacy and safety
The efficacy and safety of Daybue Stix is based on the results of the phase 3 LAVENDER study (NCT04181723) that evaluated Daybue oral solution in patients with Rett syndrome. Approval of the new formulation was based on results of a bioequivalence study, which demonstrated that both original Daybue oral solution and the new Daybue Stix for oral solution powder formulation provide comparable exposure.
The most common adverse reactions (≥10% of Daybue-treated patients and ≥2% greater than with placebo) were diarrhea and vomiting.
Sources:
Acadia Pharmaceuticals announces FDA approval of Daybue® Stix (trofinetide) for oral solution, a new powder formulation of trofinetide for the treatment of Rett syndrome. [News release]. 2025. https://acadia.com/en-us/media/news-releases/acadia-pharmaceuticals-announces-fda-approval-daybuer-stix
Daybue Stix (trofinetide) [package insert]. Acadia Pharmaceuticals. https://acadia.com/en-us/pdf/our-medicines/daybue-prescribing-information.pdf Revised December 2025. Accessed December 16, 2025.