FDA Approves Daybue (Trofinetide) for Rett Syndrome


An estimated 6,000-10,000 people within the United States are living with Rett syndrome. Prior to this month, these individuals have not had access to targeted treatment options. But this all changed when the U.S. Food and Drug Administration (FDA) approved Daybue (trofinetide) for Rett syndrome in March 2023. Daybue is an orally-administered trofinetide formulation that patients will take every day.

According to an article published in FreeThink, the drug’s approval hinged, at least in part, on data from the Phase 3 LAVENDER study. 187 patients between ages 5-20 with a confirmed Rett syndrome diagnosis enrolled in this trial. During the course of this study, researchers evaluated the safety, efficacy, and tolerability of Daybue as compared to a placebo. The study found that Daybue helped to reduce negative or limiting Rett syndrome symptoms while simultaneously improving measures such as eye gaze and hand use/communication. 

Ultimately, this treatment shows promise in improving overall function and quality-of-life for those with this condition.

Learn more about Daybue in this informative video series from the International Rett Syndrome Foundation. 

Rett Syndrome: What is this Condition? 

Resulting from MECP2 gene mutations on the X chromosome, Rett syndrome is a rare neurodevelopmental disorder that almost exclusively affects females. Most children with Rett syndrome seem to develop normally for the first six months of their lives, but between then and eighteen months, children often undergo developmental regression. Symptoms and severity vary from child to child. Potential symptoms may include:

  • Slowed brain growth that leads to microcephaly (an abnormally small head)
  • Uncoordinated breathing
  • Gait ataxia
  • Bruxism (teeth grinding) 
  • Unusual hand movements such as flapping, wringing, or rubbing  
  • Hypotonia (low muscle tone)
  • Scoliosis
  • Difficulty feeding
  • Impaired language skills
  • Irritability
  • Social anxiety
  • Seizures 

This is not an exhaustive list of symptoms. Until now, treatments for Rett syndrome have been supportive and symptomatic: physical therapy, anti-epileptic medications, behavioral therapy, speech therapy, and occupational therapy. 

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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