Eliza O'Neill was first patient in Sanfilippo trial that now has FDA approval

Eliza O'Neill, who is now 17, received the first dose of a new gene therapy for Sanfilippo syndrome in 2016. That trial led to the FDA approval of the treatment, called Fayuvi, in September. The one-time infusion is the latest step in a process that began with a pediatrician in Columbia, South Carolina, and a researcher in Columbus, Ohio.

Cara O'Neill is a pediatrician and Eliza's mother. By the time Eliza was three, she was missing developmental milestones. A test in 2013 identified Sanfilippo syndrome, a rare inherited disease. The condition prevents the body from breaking down heparin sulfate. The molecule builds up in cells, causing seizures and the loss of speech and movement. Children with the disease rarely live into their teens.

Haiyan Fu had been studying Sanfilippo in mice at Nationwide Children's Hospital since the late 1990s. She developed a therapy that uses a modified virus to deliver a working copy of the broken gene to patients. Fu nearly stopped the research in 2009 due to funding issues. Eight patient foundations, including Ben's Dream and a Cure for Kirby, provided the money needed to continue until the therapy was ready for human trials.

Glenn O'Neill, Eliza's father, helped raise the funds for the first clinical trial. In 2014, he worked with filmmaker Benjamin Von Wong to create a video for the campaign. The Saving Eliza video broke the then-current GoFundMe record. It raised one million dollars in a few weeks and eventually reached two million dollars. That money supported the trial that began in May 2016.

The trial results attracted the attention of biotech company Ultragenyx. The company acquired the rights to the therapy in 2022 and continued studying it. Ultragenyx submitted data to the FDA for review. The agency approved Fayuvi in September of this year.

Ultragenyx CEO Emil Kakkis said the treatment works best for younger children. He noted that patients who are treated at six months of age show strong results. The company set the price for the therapy at nearly $4 million. That price ties it for the second most expensive gene therapy ever, according to drug price research firm 46brooklyn. Kakkis said the company aims to treat every patient regardless of location or cost barriers.

Fu received a call from Cara O'Neill immediately after the approval announcement. Other families who had funded the early research also sent messages. Some of those families had lost children to the disease during the waiting period. Fu described the approval as good news but said it should not have taken this long to reach patients.

Eliza was six years old when she received the gene therapy. She had already lost her ability to speak, which did not return. She now communicates with picture cards and devices and attends school. This summer, she learned to float on a pool noodle in a swimming pool. Glenn O'Neill said he is proud of his daughter, acknowledging the difficulty of the road while noting her luck in receiving early treatment.