PROJECT SUMMARY/ABSTRACT The goal of this proposal is to repurpose drugs for use in combination therapy to treat primary amoebic meningoencephalitis (PAM) caused by the “brain-eating” amoeba, Naegleria fowleri (Nf). The disease usually afflicts healthy young people after exposure to warm, recreational waters. The major unmet medical need is the availability of raoidly acting, cidal drugs that can be used as part of the cocktail of drugs currently used to improve on survival rates. Presently the fatality rate is >97%. We have screened over 15K bioactive drugs, many of which are FDA approved or have been advanced into late stage development for other indications. From these we identified >50 hits that have 50% inhibitory concentrations < 10 M. We propose to assess these hits to discover drugs that have potential for repurposing for treatment of PAM. For our FIRST AIM, we will confirm the potency of these hits against a panel of N. fowleri isolates from PAM cases to confirm susceptibility is maintained. Then we will assess the rate of action of the repurposed drugs to identify the best candidates that fit a target product profile for drugs to treat PAM. These data will be used to down-select drugs for in vivo efficacy studies. In our SECOND AIM, we will use the mouse model of PAM to assess the potential for candidate repurposing drugs to treat this neglected disease. The 5 candidates that best fit the target product profile, are potent in vitro and have rapid onset of action will be assessed in a dose response model. The model will be modified to best mimic the typical PAM case; therefore drug dosing will begin 3 days post- inoculation of amoebae and will continue for up to 10 days. Drugs that produce greater than 30% cures when used alone will be assessed in combination with the current cocktail of drugs to confirm the potential for use with PAM patients.