Long Island Boy, 2, Gets 'Life-Changing Dose Of His Own Medicine'

SETAUKET, NY — Leo Wei Church was diagnosed with an ultra rare and severe neurodevelopmental disease caused by a mutation in a copy of his Transportin-2 (TNPO2) gene when he was just 4 months old.

As he suffered from significant developmental delays and frequent seizures that interfered with his breathing, his family launched the TNPO2 Foundation and initiated a research program to develop a treatment that did not yet exist, according to a news release. They hoped to save their son and help him develop to his fullest potential.

The TNPO2 Foundation partnered with Creyon Bio, a biotechnology company that develops cutting-edge individualized medicines for rare disease patients.

Using proprietary tools, AI, and custom datasets, Creyon accelerated the engineering of an antisense oligonucleotide (ASO) therapy, "Leosen," named for Leo. Just one year after the research program began, the first dose of Leosen was administered.

The treatment has been well-tolerated over nine months, according to the release. Leo has had measurable improvements in his behavior, health, and developmental progress, which his family said are "encouraging."

Leo’s case was the focus of an oral presentation last week at the American Society of Gene & Cell Therapy (ASGCT) 27th annual meeting in Baltimore.

"It is devastating to receive an ultra-rare diagnosis and have to face the reality that there are no known treatment options," said Yiwei She, Leo’s mother and founder of the TNPO2 Foundation, via news release. "Leo had access to a treatment sooner than most other children who are afflicted with such a rare genetic disorder. That he was given a chance with a personalized medicine is almost a miracle by itself, as only a handful of such projects reach this stage."

While Leo’s progress so far is encouraging, his long-term prognosis is uncertain, his family said. His family remains hopeful and is channeling all they have learned into the TNPO2 Foundation.

Their goal, they say, is to build a sustainable process for rapidly developing personalized therapeutics that can benefit children with ultra-rare diseases who are still waiting for their own miracles.

The foundation’s first project, the Project Baby Lion Pilot, is a sponsored clinical research study at Stony Brook Children’s Hospital, where Leo has visited dozens of times. The study will use a genetic sequencing tool developed at the Rady Children’s Institute for Genomic Medicine to select NICU (neonatal intensive care unit) babies who are critically ill to identify rare genetic abnormalities and variants and develop potential treatments for these conditions.

"The mission of the TNPO2 Foundation is to repeat what we did for Leo for children and families in dire need with no other options," She said. "So many children are lost in the ‘diagnostic odyssey’ and we feel strongly that they can be rescued through urgency and purposeful action."