After the eye, the brain could be the next organ in which researchers test partial reprogramming. The Seattle-based company YouthBio Therapeutics has received positive feedback from the US Food and Drug Administration (FDA) for its Alzheimer’s gene therapy YB002.
The approach
YB002 is intended to make the brain temporarily produce so-called Yamanaka factors – proteins that can return cells to a younger state. Unlike complete reprogramming, the cell is meant to retain its identity as a nerve cell. The aim is to reverse age-related epigenetic changes that, according to current thinking, contribute to the development of Alzheimer’s disease.
The evidence
- In a joint study with reprogramming researcher Alejandro Ocampo (University of Lausanne), YB002 attenuated cognitive decline in old, healthy mice.
- In further Alzheimer’s mouse models, according to the company, partial reprogramming was able to reduce disease features, slow epigenetic ageing and improve memory and learning.
- In an early advisory meeting (INTERACT), the FDA confirmed in writing that the available preclinical data support biological activity and in principle justify a first trial in humans.
What happens next?
Before patients can be treated, YouthBio still has to establish manufacturing processes, carry out toxicology studies and submit a formal application for a clinical trial. The company has not given a timeline for the start of the trial.
Assessment
The FDA’s feedback is an important signal but not an authorisation of a trial. Gene therapies in the brain are technically demanding: the gene vector must reach the right cells, and the activity of the factors must be strictly controlled to avoid unwanted cell changes. The efficacy data so far come from mice and company statements. Whether Alzheimer’s disease in humans can be influenced by rejuvenating the epigenome is an open – but exciting – question.
Note: This article is for general information only and does not replace medical advice. YB002 is an experimental therapy.
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