Following screening and study drug administration at week 0, eligible participants will be evaluated at weeks 1, 4, 8, 12, and 24. At each study visit, participants will have a physical examination including examination of the penis (all visits), vital signs, electrocardiogram (ECG) (all visits). Laboratory evaluations including chemistry and hematology will be done at V1, 3, 4, 6, and 7. Urinalysis will be done V1, 2 (prior to dosing), 3, 4, 6, and 7. Endocrine parameters and PTT, PT, sed rate and CRP will be evaluated at Visit 1, 3 and 7. The participant will complete the erectile function domain of the IIEF and Sexual Encounter Profile (SEP) at screening/baseline and at V2, (SEP and IIEF at V2 prior to dosing) V3, V4, V5, V6, and V7. In all participants, plasma specimens will be collected to assay for the presence of hSlo DNA by PCR (V2-V7). These will be kept frozen at -20°C or less at the site for eventual assay by Sponsor.