Trofinetide

Trofinetide is a synthetic analog of glycine-proline-glutamate (GPE), the three-amino-acid fragment released from IGF-1 in the brain. Originated by Neuren Pharmaceuticals, it is administered orally. DAYBUE and DAYBUE Stix are the product names in the published account.

Rett syndrome is a rare genetic neurodevelopmental disorder affecting predominantly girls, with loss of previously acquired skills, movement difficulties and impaired communication. US approval in 2023 made trofinetide the first medicine specifically approved for the condition. Its prior Fragile X and traumatic-brain-injury studies did not create approved indications.

The label does not establish a precise mechanism for clinical benefit in Rett syndrome. Preclinical hypotheses include less neuroinflammation through microglial/astrocyte modulation, support for dendritic and synaptic maturation, and normalization of IGF-1-related central signaling. These mechanisms aim to improve circuits affected by MECP2 loss; they are not proof of benefit across all neurodevelopmental conditions.

LAVENDER randomized 187 females with Rett syndrome for 12 weeks. Because the condition lacks a single response biomarker, outcomes included the caregiver-rated Rett Syndrome Behaviour Questionnaire and clinician global impression. Both measures improved significantly versus placebo; the questionnaire comparison had P = 0.0175.

The most frequent treatment effects were gastrointestinal. These results concern Rett syndrome and should not be extended to the earlier exploratory programs.

DAYBUE was FDA-approved in 2023 for Rett syndrome in adults and children aged two years and older. The prescribing information revised in December 2025 also includes DAYBUE Stix powder, which is mixed into a solution. Medicines that worsen diarrhea or dehydration need particular care during treatment.

A double-blind, placebo-controlled Phase 2 study in adolescent and adult males with Fragile X syndrome lasted 28 days. The higher dose met prespecified exploratory efficacy criteria on several Fragile X measures. The authors treated this as an initial signal, not confirmatory evidence.

No successful registration study established that use. Earlier traumatic-brain-injury work likewise failed to produce an approved indication. The limited predecessor-program findings must remain distinct from the positive Rett syndrome registration evidence.

Common label-listed effects include diarrhea, vomiting, fever, reduced appetite, fatigue, anxiety, seizure and cold symptoms. Most patients experience diarrhea. Fluid management and adjustment of other medicines may be needed when diarrhea threatens hydration.

Severe vomiting can lead to aspiration of stomach contents. Significant weight loss is another concern, so body weight is monitored. These risks are part of the product-specific treatment context rather than a general safety profile for every IGF-1-related peptide.