Primary Efficacy: To identify patients achieving Complete Cure in the target toenail at Week 52.~Secondary Efficacy: To identify patients that have achieved 1) Clinical Cure, 2) Mycological Cure, and/or 3) Positive Response in the target toenail at Week 52.~Plasma Pharmacokinetics: To characterize concentrations of terbinafine and major metabolite in a subpopulation of patients over the study period.~Nail Pharmacokinetics: To characterize concentrations of terbinafine and major metabolite in distal nail clippings in patients over the study period.~HSG Safety and Tolerability Profile: To establish from plasma pharmacokinetics, related adverse events, treatment site reactions, pain, clinically significant changes in medical condition and/or medications, and clinically significant changes in liver function, serum chemistry, urinalysis, and complete blood count over the study period.~Subungual Topical Procedure: To establish the ease and durability of once monthly and once bi-monthly HSG subungual topical treatments, the Investigator will record at selected time points 1) nail measurements indicating progressive clearing, 2) the ease and depth of each topical administration, 3) the investigational drug volume administered each treatment, and 4) patient tolerability.
The key objective is to establish the efficacy, safety, tolerability, and pharmacokinetics of investigational drug Hallux Terbinafine Subungual Gel (HSG) administered over 44 weeks to patients with distal-lateral subungual onychomycosis (DLSO).