Study to Evaluate the Efficacy and Safety of Topical MOB015B in the Treatment of Mild to Moderate Distal Subungual Onychomycosis (DSO)

Inclusion Criteria: 1. Males or females 18 - 75 years of age 2. Distal subungual onychomycosis (DSO) of at least one of the great toenail(s) affecting 20% to 60% of the target nail 3. Positive culture for dermatophytes 4. Signed written informed consent Exclusion Criteria: 1. Proximal subungual onychomycosis 2. Distal subungual onychomycosis of both great toenails where involvement has extended into the proximal portion of the target nail (unaffected proximal nail is less than 3 mm) 3. Target toenail thickness more than 3 mm 4. "Spike" of onychomycosis extending to eponychium of the target toenail 5. Presence of dermatophytoma (defined as thick masses of fungal hyphae and necrotic keratin between the nail plate and nail bed) on the target nail 6. Other conditions than DSO known to cause abnormal nail appearance 7. Presence of toenail infection other than dermatophytes 8. Previous target toenail surgery with any residual disfigurement 9. Topical treatment of the nails with other antifungal medication or medical device within 6 weeks before screening/Visit 1 10. Systemic use of antifungal treatment within 6 months before screening/ Visit 1 11. Severe moccasin tinea pedis 12. Signs of severe peripheral circulatory insufficiency 13. Uncontrolled diabetes mellitus 14. Known immunodeficiency 15. Participation in another clinical trial with an investigational drug or device during the previous 3 months before Baseline/ Visit 2 16. Known allergy to any of the tested treatment products 17. A positive pregnancy test indicating pregnancy in a woman of childbearing potential at Baseline/ Visit 2 18. Females who are pregnant or breastfeeding 19. Pre-menopausal (last menstruation ≤ 1 year prior to screening) sexually active women who are of childbearing potential and are not practicing an acceptable method of birth control, or do not plan to continue practicing an acceptable method of birth control throughout the trial 20. Patients previously randomized in this study 21. History of, or current drug or alcohol abuse 22. Psychiatric condition that might limit the participation in the study and/or that lead to the assumption that the patient's ability to completely understand the consequences of consent is missing 23. Close affiliation with the investigator (e.g. a close relative) or persons working at a study site, or patient who is an employee of the sponsor's company 24. Patients who are institutionalized because of legal or regulatory order 25. Any diseases or circumstances in which the patient should not participate in the study in the opinion of the investigator