ION-717 - A Major Step Forward in Prion Disease Therapy
- Cathy Tse
- Jul 18
- 2 min read
An overview of prion disease
In the 1980s to 90s, a major outbreak of mad cow disease brought the world’s attention to prions - the causative agent behind this lethal brain disease. Prions are a type of protein that can trigger normal proteins in the brain to fold abnormally. As abnormally-folded proteins build up in the brain, this damages brain function and leads to memory problems, personality changes, and trouble with movement.
The patient-scientist developing a cure for prion disease
Prion diseases are rare, with approximately 300 cases reported annually in the US. They are usually contracted through eating prion-infected meat (as is the case with mad cow disease), but can also be inherited. Sonia Vallabh is one of those individuals who inherited a prion disease called fatal familial insomnia, and she, along with her husband Eric Minikel, is on a mission to develop the first-ever treatment for prion disease. Vallabh aims to utilise gene therapy to reduce prion protein levels in the body, thereby delaying the onset of prion disease. In collaboration with Ionis Pharmaceuticals, ION-717 was developed as an investigational antisense oligonucleotide that inhibits the production of prion protein and is currently in the early stages of clinical trials.
How ION-717 works
Prion proteins are produced from the transcription and translation of prion protein genes. ION-717 disrupts this chain of events by forming a complex with the RNA sequence that would otherwise go on to produce prion proteins through translation. The PrProfile trial will investigate the safety, tolerability, and pharmaceutical profile of ION-717 in adults with a confirmed diagnosis of definite or probable prion disease.
Why ION-717 matters
Despite the devastating prognosis of prion diseases, there are currently no preventative or curative measures, and much remains unknown about prions. The PrProfile trial is expected to yield its first results by the end of 2025, and pre-clinical animal model studies have demonstrated delayed onset of prion disease, increased survival duration, and reversal of neurological damage. We will have to wait and see if these findings translate into human populations. The best-case scenario would be for ION-717 to progress in the clinical development pipeline, bringing it one step closer to regulatory approval for the treatment of prion disease.
References
Image credit: Dunning, H. 'Crucial step in formation of deadly brain diseases discovered' (2021). Imperial College London.
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