This is a Pre-IDE, prospective, multicenter, randomized, parallel-group, double-blind, vehicle- controlled study to evaluate safety and effectiveness of Nail Genesis DLSO Product for the treatment of DLSO compared with vehicle in infected great toenails in a total of 338 males and non-pregnant, non-lactating, females between 18 and 65 years of age (inclusive). Subjects will be randomized in a 2:1 ratio to receive either Nail Genesis DLSO Product or vehicle.

Subject eligibility will be determined during a Screening assessment. Subjects will complete a 4week washout period after discontinuation of a topical product or a 12-month washout period after discontinuation of an oral product or light-based therapy prior to randomization. Eligible subjects will be randomized in a 2:1 ratio to receive Nail Genesis DLSO Product or vehicle, respectively. During the 52-week trial, study medication will be administered once daily to the target toenail for 48 weeks.

A subject will be considered to have completed the study when he or she has completed the study assessments at Week 52. The 52-week visit is for follow-up safety assessments.

Inclusion Criteria:

• Subject is male or female, and 18 to 65 years of age, inclusive.
• Subject has nail fungal infection of at least one great toenail (per visual assessment, positive KOH preparation, and positive dermatophyte culture).
• Subject has target toenail showing 20-50% involvement without matrix (lunula) involvement.
• Subject has 3 mm of unaffected nail (from proximal nail fold) on target toenail.
• Subject has target toenail thickness of 3 mm or less.
• Subject must be physically able to reach toes to clean, trim, and apply product to the target toenail.
• Subject is willing and available to return for study follow up.
• Subject or legal representative is able to understand and provide signed consent for participating in the study.
• Female subject of childbearing potential has negative urine pregnancy test.
• Females must be post-menopausal or must agree to use approved contraceptives (actions, de- vices or medications to prevent or reduce the likelihood of pregnancy) throughout the study (abstinence is NOT an accepted form of contraception).

Exclusion Criteria:

• Subject has known hypersensitivity or allergy to the product materials.
• Subject has negative KOH preparation or dermatophyte culture.
• Subject has dermatophytoma on target toenail.
• Subject is enrolled in another investigational drug, device, or product protocol that would interfere with this study.
• Subject is using other topical or pharmaceutical treatments for any nail conditions; a wash-out period of at least four weeks after discontinuation of a topical product or 12 months after discontinuation of an oral product or light-based therapy for treatment of nail fungus is required.
• Subject has history of immunosuppression and/or clinical signs indicative of possible immunosuppression.
• Subject with possible chronic disease, including: diabetes, psoriasis, immune deficiency (HIV), severe foot injury, chronic vascular disease, or in which delayed treatment (approved treatment) of DLSO for one year could present a significant health concern.
• Subject has presence of toenail infection other than dermatophytes on target toenail.
• Subject has any disease/condition that might cause toenail abnormalities or interfere with evaluation.
• Subject has had previous toenail surgery on target toenail.
• Subject is a pregnant or nursing female.
• Subject is an Investigator, Nail Genesis' personnel, or Nail Genesis' Scientific Advisory Board (SAB) members, or their immediate family.