Arthur Beisang, MD, Department of Pediatrics at Gillette Children’s Specialty Healthcare in Saint Paul, Minnesota, discusses Daybue (trofinetide) Stix, a new formulation of the treatment for Rett syndrome.
Rett syndrome is a neurodevelopmental condition that primarily affects girls. People with the disease appear to have normal psychomotor development during the first 6 to 18 months of life, followed by a developmental “plateau,” and then rapid regression in language and motor skills. Additional signs and symptoms may include repetitive, stereotypic hand movements, fits of screaming and inconsolable crying, autistic features, panic-like attacks, teeth grinding, episodic apnea and/or hyperpnea, gait ataxia and apraxia, tremors, seizures, and slowed head growth. Classic Rett syndrome is most commonly caused by genetic changes in the MECP2 gene.
Trofinetide is a synthetic analog of the N-terminal tripeptide of insulin-like growth factor-1, approved for treatment of Rett syndrome in 2023. Daybue Stix is an oral, dye- and preservative-free powder formulation of the treatment approved in December 2025 and now available in the US for patients 2 years of age and older.
The new formulation has the same efficacy and safety profile of the original formulation, based on results from the phase 3 LAVENDER (NCT04181723) study, while also giving patients flexibility and choice in dose volume and taste of treatment. The approval of this new formulation was informed by the results of a bioequivalence study, which demonstrated that both the original Daybue oral solution and the new Daybue Stix formulation provide comparable exposure.
Daybue Stix comes as a powder that can be mixed with a variety of water-based liquids to customize to a patient’s preference of taste. The product comes in individual packets that are easily portable and do not have to be refrigerated unlike the original formulation.
A recent publication of expert recommendations for real-world use of trofinetide in Rett syndrome emphasized the importance of patient-centered approaches. Experts from International Rett Syndrome Foundation-designated centers of excellence agreed that treatment options that allow for individualized decision making help optimize outcomes for patients, families, and caregivers.
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To learn more about Rett syndrome, visit https://checkrare.com/rett-syndrome/
