Safety and Pharmacokinetics of Efinaconazole Topical Solution in Subjects With Mild to Severe Onychomycosis

This is an open label, single-arm study designed to evaluate the safety and PK of a once
daily topical application of efinaconazole in the treatment of pediatric subjects with mild
to severe onychomycosis of the toenails.

Key Inclusion Criteria:

- Male or female subjects of any race, 6 to 16 years of age (inclusive). PK Subset: Male
or female subjects of any race, 12 to 16 years of age (inclusive).

- Verbal and written informed consent/assent obtained from the subject and/or their
parent or legal guardian.

- Good general health, as assessed by the investigator, based on the subject's medical
history, physical examination, and safety laboratory tests.

- Target great toenail for all subjects, and both great toenails for subjects in the PK
subset, must have evidence of toenail growth, per subject's report that monthly
clipping is needed.

- Subjects and their parents/legal guardians are willing to comply with study
instructions and return to the investigational center for all required visits (a visit
schedule with the length of each visit will be provided to ensure that the subject can
meet the requirements and have adequate transportation).

Key Exclusion Criteria:

- Females who are pregnant, nursing an infant, or planning a pregnancy during the study
period.

- History of immunosuppression and/or clinical signs indicative of possible
immunosuppression, as determined by the investigator, or known human immunodeficiency
virus infection.

- History of diabetes that is uncontrolled as determined by the investigator (diabetes
that is controlled by diet or medication does not exclude a subject).

- Presence of any toenail infection other than or in addition to dermatophytes, such as
Scytalidium as determined by the investigator (candidal onychomycosis infection,
concurrent with a positive dermatophyte culture, is acceptable).