An Open-label, Single Ascending Dose Study to Evaluate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of Intrathecally Administered PrP-siRNA in Adults Diagnosed With Symptomatic Prion Disease and in Pre-symptomatic Adults at Genetic Risk for Prion Disease.

Key inclusion criteria for symptomatic patients: 1. clinically manifested symptoms of prion disease, in the opinion of the investigator 2. a diagnosis of probable prion disease according to CDC criteria 3. a positive CSF RT-QuIC or PRNP genetic test 4. no more than moderate functional impairment as quantified by an MRC-PDRS score ≥15 5. availability of a caregiver to assist with study procedures Key inclusion criteria for pre-symptomatic patients: 1. lack of clinically manifested symptoms of prion disease, as demonstrated by an MRC Score of 20, a MoCA score between 24-30 inclusive, and a ne…