
14/07/2025
We have an update on the progress of the gene therapy for Sanfilippo syndrome type A developed by Ultragenyx (UX111). The FDA in the USA has been considering whether UX111 should be given regulatory approval and was expected to give a decision next month. Over the weekend, we received some disappointing news: there has been a delay.
The paperwork submitted to the FDA includes not only all the data from the clinical trials relating to the safety and effectiveness of the gene therapy, but also detailed plans on how the gene therapy will be manufactured and quality-controlled once approved. The FDA has asked for more information related to manufacturing facilities and processes before it makes a decision. Manufacturing gene therapies is complex, so it is important to ensure the gene therapy product is consistently safe and effective.
Unfortunately, this may take several months to address and then the FDA has a further 6 months to give a decision on approval of UX111. This delay is very disappointing because it is urgent to get this treatment to children as soon as possible. Ultragenyx is doing everything they can to address the FDA’s request for further information, and in this letter to the Sanfilippo community, they say that the issues raised are “readily addressable and we have already addressed many of them”. You can see this letter here: https://www.childhooddementia.org/getasset/1ZTK7L
Advocates around the world are continuing to work together to ensure the FDA understands the urgency of this approval. We also note that FDA approval does not mean that Australian patients will be able to access the gene therapy, it will need to be approved by the Australian regulatory authorities (TGA) and reimbursed through the PBS. It can typically take several years for a drug to become available in Australia after it is approved overseas.
Please note: Sanfilippo Children’s Foundation has ceased to operate as a separate entity. Sanfilippo Children’s Foundation’s mission will be carried forward by Childhood Dementia Initiative, the organisation established to advocate for all children with dementia through research, care, and policy.