Systematic review of therapeutic interventions in human prion disease

Background: The potential threat of a large outbreak of variant Creutzfeldt-Jakob disease initiated a proliferation of research into the understanding and treatment of human prion disease. However, clinical research is at an early stage with a pressing need for objective evaluation of treatments to inform the design of future studies. Methods: We aimed to summarize existing research on outcomes of patients with prion disease, considering any published clinical study and patient series with data on disease progression. Methods were prespecified in a protocol and studies were identified from systematic searches of multiple sources. Results: One randomized trial was identified. Many studies were flawed or poorly reported, and therefore interpreted cautiously. One hundred forty published patient series revealed wide ranges in disease duration for each of the prion diseases. Thirty-three studies described the use of 14 drugs, 10 which were reported in single studies of three or fewer patients and one which was reported for two individual cases. Effects of four drugs were examined in more detail, with mixed results. The only current reliable evidence is from the single randomized trial suggesting that flupirtine may slow cognitive decline. Based on published information identified by this review, survival of most treated patients is within the ranges reported in the untreated patient series. Conclusions: Thirty years of clinical investigation of patients with prion disease has resulted in little progress in either defining or evaluating potential treatments. Disease course and treatment of all patients must be evaluated within a structured framework, preferably within randomized controlled trials.