Prion diseases are a large group of related neurodegenerative conditions, which affect both animals and humans and include Creutzfeldt-Jakob disease (CJD) and Gerstmann-Sträussler-Scheinker (GSS) in humans, Bovine Spongiform Encephalopathy (BSE, or "mad cow disease") in cattle, Chronic Wasting Disease (CWD) in mules, deer and elk, and scrapie in sheep. All these diseases have long incubation periods, rapid progress once clinical symptoms begin and are fatal. No effective form of treatment is currently available; however, increased understanding of their pathogenesis has recently led to the promise of effective therapeutic solutions in the near future.

Pentosan polysulfate sodium is being tested in patients and shows promising results based on an animal study (1). It does not cross the blood-brain barrier and has been delivered by intraventricular administration to symptomatic patients. In the only reported vCDJ case study using this approach, no obvious side effects were observed, and the clinical symptoms appeared to be slightly attenuated, although brain atrophy progressed based on CT scans (2).

The background rationale for treatment with pentosan polysulfate sodium rests on experimental in vitro and in vivo work, indicating that it has effects on prion protein production, replication and associated cell toxicity. In vivo experimental results are showing that pentosan polysulfate sodium has a prophylactic effect in various animal models and if given to animals at a time relatively close to the point of experimental infection, then there may be an increase in the incubation period of disease, resp. a prolongation of the time between inoculation and the appearance of clinical disease.

References
1) Doh-ura K et al. Treatment of Transmissible Spongiform Encepalopathy by Intraventricular Drug Infusion in Animal Models. Journal of Virology 2004; 78(10): 4999-5006.
2) Todd NV et al. Cerebroventricular infusion of pentosan polysulphate in human variant Creutzfeldt-Jakob disease. Journal of Infection 2005; 50: 394-396.