April 21, 2025
Dear Rett syndrome community
A little over a year ago, DAYBUE® (trofinetide) was approved by the FDA as the first and only treatment for Rett syndrome in adults and children 2 years of age and older. Over the past year, it has been a privilege to introduce DAYBUE to the Rett community in the United States, and to meet so many families and clinicians treating Rett. On behalf of the entire Acadia team, thank you!
We are writing to share a series of updates to address some of the common questions that we have received from the community. We hope you will find these updates helpful, whether your loved one is currently on DAYBUE, has had experience with DAYBUE, or if you are now considering treatment.
How many people have been prescribed DAYBUE since approval?
Over 1500 people living with Rett syndrome have started DAYBUE. The people who have been prescribed DAYBUE are representative of the Rett population and have a variety of Rett symptoms and disease severities. Girls and boys as young as 2 have been prescribed DAYBUE. Approximately 25% of people prescribed DAYBUE are older than 21 years and as old as 67 years.
What types of improvements have families observed in their child with DAYBUE treatment over the past year? How consistent are they with the clinical trial?
Caregivers have reported seeing meaningful improvements in areas such as mood, eye gaze, vocalizations, and other Rett behaviors, which is consistent with the results seen in the LAVENDER™ study. Caregivers have shared that the impact of these changes has ranged from improved communication of choices and needs to more positive family outings.
Because every person living with Rett syndrome has unique symptoms and needs, the types of improvements and what they can mean for your child are going to be unique too. It’s important to make a baseline assessment of your loved one’s symptoms and involve the entire care team in tracking changes and improvements over time.
Learn more about the meaningful benefits caregivers have reported with DAYBUE in their loved one by watching “Our story with DAYBUE” videos and visiting the DAYBUE Sparkle Gallery.
Can you tell us more about the patient journey to date?
Approximately 7 out of 10 people who have started DAYBUE remain on treatment after 6 months. Many caregivers and doctors partner together to put a plan in place that allows them to remain on therapy for the long-term to observe improvements over time with continued treatment with DAYBUE.
We also understand that some caregivers have had to discontinue therapy because of difficulty managing side effects. It is important to understand that just as every person living with Rett syndrome is different, so is their response to treatment. The only way to know how your loved one will respond to DAYBUE is by actively engaging with your physician to effectively manage the benefits and risks of treatment for the long-term. Before starting DAYBUE, it is important to work with your doctor to put a plan in place so you can manage the overall treatment experience for your loved one.
What are the most common side effects with DAYBUE?
We understand that many of you have questions about both the benefits and possible side effects of DAYBUE and want to learn more.
Diarrhea and vomiting are the most common side effects of DAYBUE that can sometimes be severe. DAYBUE can also cause weight loss. Other possible side effects include fever, seizure, anxiety, decreased appetite, tiredness, and the common cold.
Because every person living with Rett syndrome is different, your child may have a different response to treatment. Before starting DAYBUE, it is important to work with your child’s doctor to put a plan in place so you are ready for any side effects that your child may experience. Many caregivers are able to work with their doctor to effectively manage side effects, while others need more support.
See below for additional Important Safety Information of DAYBUE. You can also schedule time with a Patient and Community Educator to learn more.
If I am concerned about diarrhea, what should I discuss with my child’s doctor before starting DAYBUE?
It is important to discuss your concerns and work with your doctor to determine what is right for your child. Before starting DAYBUE, your doctor will consider your child’s medical history, gastrointestinal issues, and how his or her body may tolerate DAYBUE, to determine the right dose for your child. Always follow your doctor’s instructions.
If diarrhea is a concern, your child’s doctor will use their clinical judgment and experience, and may decide to start with a lower dose and increase to the FDA-recommended dose over time.
It is important to note that improvements may not occur until your child reaches the recommended dose and continues treatment. The impact of this approach on diarrhea was not studied in LAVENDER. The LAVENDER study findings were based on starting patients at the FDA-recommended dose, which is based on weight, and continuing treatment for 12 weeks. Individual patient response may vary.
If my child starts DAYBUE, will they still be able to participate in future gene therapy clinical trials?
There are no limitations in the DAYBUE product label regarding participation in future Rett syndrome gene therapy clinical trials. However, in some instances, there may be a requirement to stop treatment with DAYBUE prior to a new trial. This is to ensure that the safety and preliminary efficacy of the trial medication can be evaluated appropriately.
For further information about clinical trials for Rett syndrome, please contact the sponsor of the study, review study information on clinicaltrials.gov, or discuss with your doctor.
Does Acadia provide insurance coverage support and financial assistance?
Once your child is prescribed DAYBUE, you’ll have access to Acadia Connect®, a patient and family support program that connects you and your family with educational support and resources throughout your DAYBUE treatment journey. Acadia Connect will help you with:
Understanding and verifying insurance coverage
Information on financial assistance options
Support and education throughout the DAYBUE treatment journey
With support from Acadia Connect, approximately 99% of families pay less than $10 for DAYBUE*.
*~99% represents a combination of Medicare, Commercial, Medicaid, Managed Medicaid, and other policies. Around 1% of patients may pay more than $10 for their prescription as reported by the specialty pharmacy authorized to distribute and dispense DAYBUE. Q2 to Q4 2023 data.
How can I learn more about DAYBUE?
Please join us at an upcoming Discovering DAYBUE event. The Discovering DAYBUE Caregiver Series features educational sessions, presented by Acadia Pharmaceuticals Inc. Sign up to learn about DAYBUE, and to hear from doctors and caregivers with DAYBUE experience.
Missed an event? Don’t worry! Our events are recorded and saved to fit into your schedule and can be accessed on our Past Events page.
When will DAYBUE be available outside of the United States?
We are assessing potential regulatory pathways, market dynamics and are evaluating a variety of pathways to make our rare disease portfolio available to patients. Acadia has initially prioritized the regulatory activities in Canada, Europe, and Japan.
How can I learn more about DAYBUE and speak to someone from Acadia?
Our Patient and Community Educators are available to help answer your questions about DAYBUE or understanding a Rett syndrome diagnosis. Connect one-on-one with a Patient and Community Educator for a partner in navigating your family’s Rett syndrome journey.
Acadia Medical Information team contact:
Caregivers can reach the Acadia Medical Information team here.
Follow us on social media at the following channels:
As always, we remain grateful to the Rett community and the patients and their families who are at the center of all we do at Acadia, and the healthcare professionals who care for them.
Please review Important Safety Information below and discuss it with your loved one’s doctor if you have any questions or concerns.
Warm regards,
Acadia Rett Syndrome Team
