Update as of February 26, 2026

Cure Sanfilippo Foundation Chief Science Officer Cara O’Neill, MD, was among four expert witnesses testifying before the U.S. Senate Special Committee on Aging to explore how U.S. Food and Drug Administration processes and evolving standards unintentionally delay patient access to safe and effective therapies, particularly for individuals living with rare diseases.

“Congress has given FDA the tools of flexibility it needs to accelerate approvals for these devastating diseases. But sadly, flexibility and speed are not actually what most rare disease patients are witnessing. Transformative therapies are at FDA's doorstep. And so with great respect, families are pleading for FDA to unlock the door and move with urgency so that our children can have a chance at the life they deserve.”

- Dr. Cara O’Neill, Chief Science Officer and Co-Founder, Cure Sanfilippo Foundation, and mother of Eliza (age 16)

Watch the full testimonial here

Update as of February 12, 2026

Ultragenyx received an Incomplete Response Letter from the FDA which requested additional supportive documentation around the Chemistry, Manufacturing,and Controls (CMC) portion of the UX111 Sanfilippo A gene therapy submission. Ultragenyx plans to provide the additional documents to the FDA as quickly as possible and will then resubmit their BLA for accelerated approval.

"One year has passed since the original BLA submission. Our children with Sanfilippo syndrome have suffered an additional year of neurologic injury. Heartbreakingly, setbacks like these have real consequences for children and families," said Cure Sanfilippo Foundation President Glenn O'Neill. "We remain hopeful that the U.S. Food and Drug Administration will honor its commitment to accelerate approvals of treatments for rare, fatal pediatric diseases like Sanfilippo syndrome."

Read Ultragenyx's initial press release about the resubmission

What is happening?

A promising gene therapy for Sanfilippo syndrome—a relentless disease that robs children of speech, mobility, and independence—is stalled by FDA delays. Trials show UX111 can slow or preserve these abilities, offering hope where no treatments exist.

Yet despite strong data, approval was rejected over minor manufacturing issues, delaying access for at least 6–12 months. For children with Sanfilippo, every month means irreversible loss.

Our kids are losing their voices, so we need yours to help by contacting HHS Secretary Kennedy and FDA Commissioner Makary and ensure:

Swift review of resubmissions for rare disease drugs, especially for Sanfilippo and Barth.
Engagement with sponsors to resolve minor issues before rejecting applications.
The FDA holds direct meetings with patient communities impacted by recent delays, including Sanfilippo and Barth.
The FDA makes full use of existing regulatory flexibility when the science is strong and safety risks are minimal.

Help us call for change

To help, pick one or all three of the options below. This isn’t just about Sanfilippo. Other rare disease patients are facing similar delays, and we need reform.

1) Help us reach Congress

Send an email (30 sec)

> Email your Representative

Add your information to this template letter and it will automatically be sent to your members of Congress.

Make a call (1-2 min)

> Phone numbers

> Sample call script

Calls are even more important! Staffers track every single call that comes in to show members of Congress what is important. Staffers will simply be listening and taking notes, so don't stress!

Request a meeting (10 min)

> Phone numbers

> Talking points

Call and request to meet with your Congress member using the talking points we've prepared. You don't have to be an expert! Meetings can be in person or virtual.

2) Sign this urgent letter to the FDA

Sign the petition letter (30 sec)

> Sign the letter

This letter is to FDA Commissioner Makary and others at the FDA. It is intended to draw attention to our rare disease community's urgent need for approved treatments. We need your help to send a message that as a rare disease community, we are watching, and we are strong together....

3) Share stories on social and tag decision-makers

Share posts from Sanfilippo families sharing their stories or engage with them on social media to amplify the message.

Social media platforms: BlueSky, Facebook, Instagram, TikTok, TruthSocial, Twitter/X, YouTube, etc.

Tag:
• X: @US_FDA @MartyMakary @VPrasadMDMPH + your Congress reps

• Instagram: @fda @martymakary @drmakaryFDA @seckennedy

@robertfkennedyjr @karolineleavitt

+ your local Congresspeople and media

Hashtags: #ApproveHopeNow #NoMoreDelays #WalkTheTalkMakary

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About Sanfilippo Syndrome

Sanfilippo Syndrome is a terminal, degenerative disease that causes children to lose all the skills they’ve gained, suffer seizures and movement disorders, experience pain and suffering, dementia, and then die usually in their teen years. It is often referred to as being like a late-stage Alzheimer’s, but in children.

Sanfilippo is a rare genetic disease. Parents are unknowingly carriers of a genetic mutation that causes the children to have this condition. It is estimated that 1 in 70,000 births result in Sanfilippo. This equates to many thousands around the world suffering from this disease. Because it is rare, it is often left to parent-led organizations to spread awareness and fund research.