Daybue, 1st approved Rett treatment, now available to patients in the US

Support program also available to provide education and resources

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

Share this article:

Share article via email
A person speaks into a microphone with the words

Daybue (trofinetide) is now available in the U.S. to treat Rett syndrome in patients 2 and older, according to the therapy’s developer Acadia Pharmaceuticals.

The announcement comes about a month after Daybue became the first therapy to be approved for Rett syndrome by the U.S. Food and Drug Administration (FDA), offering a new era of hope to the community.

“The Rett syndrome community has been waiting a long time for a drug to treat this debilitating disorder,” Steve Davis, CEO of Acadia, said in a company press release. “We have worked hard to make DAYBUE available as quickly as possible following FDA approval.”

Recommended Reading
main graphic for column titled

FDA approval of Daybue gives the Rett community hope for the future

Support program available to help patients starting or continuing on Daybue

Acadia is offering a support program called Acadia Connect to provide assistance and offer resources to Rett patients who are starting or continuing treatment with Daybue. Information about the program is available online at, or by phone at 1-844-737-2223 weekdays from 8 a.m. to 8 p.m. ET.

Daybue is a liquid solution that can be taken by mouth or a feeding tube. Its active ingredient is an analogue of glypromate, a protein fragment that naturally occurs in the brain and is thought to have anti-inflammatory effects and help promote the development of connections between nerve cells, which is impaired in Rett syndrome.

FDA approval of the therapy was based on findings from the Phase 3 LAVENDER clinical trial (NCT04181723), which enrolled 187 girls and women with Rett syndrome, ages 5 to 20. Participants were randomly assigned to take Daybue or a placebo twice daily for about three months.

Results showed the treatment outperformed the placebo at improving caregiver- and clinician-rated assessments of symptom severity, especially with regard to anxiety/fear, body rocking, and blank facial expressions.

“Having a therapy that has been shown to address multiple symptoms of Rett syndrome provides a promising treatment option that may lead to meaningful impact for patients and their families,” said Alan Percy, MD, an investigator on the LAVENDER trial and professor at the University of Alabama at Birmingham.

“Following my experience as an investigator in the Lavender Phase 3 study I have already initiated the process of prescribing DAYBUE for my patients,” Percy said. “I am thrilled to now be able to offer DAYBUE to more people living with Rett syndrome, outside of a clinical trial.”

Most participants who finished the LAVENDER study are continuing on Daybue and being monitored for long-term outcomes in the open-label extension trial LILAC (NCT04279314). Acadia is also running a study called DAFFODIL (NCT04988867), testing the therapy in 15 Rett girls ages 2 to 5.