A New Drug Application (NDA) for trofinetide has been submitted to the Food and Drug Administration (FDA) for the treatment of Rett syndrome in patients 2 years of age and older.

Trofinetide is a novel synthetic analogue of the amino-terminal tripeptide of IGF-1 designed to treat the core symptoms of Rett syndrome by reducing neuroinflammation and supporting synaptic function. The NDA is supported by data from the randomized, double-blind, placebo-controlled phase 3 Lavender study (ClinicalTrials.gov Identifier: NCT04181723), which evaluated the efficacy and safety of trofinetide in 187 females 5 to 20 years of age with Rett syndrome.

Patients were randomly assigned to receive trofinetide or placebo orally or via gastrostomy tube twice daily for 12 weeks. The coprimary endpoints were the change from baseline to week 12 in the Rett Syndrome Behaviour Questionnaire (RSBQ) total score (a caregiver assessment) and the Clinical Global Impression-Improvement (CGI-I) score (a physician assessment). 

Findings from the study showed that treatment with trofinetide demonstrated a statistically significant improvement over placebo on the coprimary endpoints. Trofinetide also met a key secondary endpoint demonstrating a statistically significant improvement from baseline to week 12 in the Communication and Symbolic Behavior Scales Developmental Profile Infant-Toddler Checklist–Social composite score compared with placebo.

The FDA previously granted Fast Track, Orphan Drug, and Rare Pediatric Disease designations to trofinetide for this indication. 


  1. Acadia Pharmaceuticals submits New Drug Application to the US FDA for trofinetide for the treatment of Rett syndrome. News release. Acadia Pharmaceuticals Inc. Accessed July 18, 2022. https://www.businesswire.com/news/home/20220718005745/en/Acadia-Pharmaceuticals-Submits-New-Drug-Application-to-the-U.S.-FDA-for-Trofinetide-for-the-Treatment-of-Rett-Syndrome
  2. Acadia Pharmaceuticals announces positive top-line results from the pivotal phase 3 Lavender trial of trofinetide in Rett syndrome. News release. Acadia Pharmaceuticals Inc. December 7, 2021. Accessed July 18, 2022. https://www.businesswire.com/news/home/20211206005778/en/Acadia-Pharmaceuticals-Announces-Positive-Top-line-Results-from-the-Pivotal-Phase-3-Lavender-Trial-of-Trofinetide-in-Rett-Syndrome