A total of 12 subjects will be randomly assigned in a 3:1 ratio to receive a multiple dose of either CNM-Au8 (n=9) or placebo (n=3) once daily for 21 days at an initial dose level of 15 mg CNM-Au8. Additional cohorts of 12 subjects will be enrolled to investigate escalating multiple doses of CNM-Au8 at 30, 60, and 90 mg CNM Au8 administered once daily for 21 days. Cohorts will be balanced by sex with no more than 2/3rd of subjects being of one sex.