Safety and Efficacy Study of SKX-16 in Participants With Mild to Moderate Distal Subungual Onychomycosis

A Phase 2, Multicenter, Randomized, Double-Blind Study Evaluating the Safety and Efficacy of SKX-16 (Luliconazole 10% Solution) in Participants With Mild to Moderate Distal Subungual Onychomycosis of the Toenails

This is a parallel group, double blind, vehicle-controlled study in which SKX-16 or vehicle (2:1 randomization) is applied once a day for 52 weeks to all affected toenails to participants with mild to moderate distal subungual onychomycosis (DSO) of the toenails involving between 20 to 50% of at least one great toenail at Screening.

Study Overview

• Status: Not yet recruiting
• Conditions: Onychomycosis of Toenails
• Intervention / Treatment: Drug: SKX-16 (Luliconazole 10% Solution); Drug: Vehicle solution

• Study Type: Interventional
• Enrollment (Estimated): 204
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Mehria Afzal Patient Recruitment and Site Engagement Specialist; Phone Number: 326 866-575-3111; Email: mafzal@inderocro.com

Study Locations

• United States
  • California
    • Los Angeles, California, United States, 900045
      • SKX16B01 Clinical Study - Site 105
      • Contact: Mehria Afzal Pts Recruitment and Site Engagement Specialist, Indero (CRO); Phone Number: 866-575-3111; Email: mafzal@inderocro.com
    • San Francisco, California, United States, 94115
      • SKX16B01 Clinical Study - Site 101
      • Contact: Mehria Afzal Pts Recruitment and Site Engagement Specialist, Indero (CRO); Phone Number: 866-575-3111; Email: mafzal@inderocro.com
  • Florida
    • Miami, Florida, United States, 11760
      • SKX16B01 Clinical Study - Site 104
      • Contact: Mehria Afzal Pts Recruitment and Site Engagement Specialist, Indero (CRO); Phone Number: 866-575-3111; Email: mafzal@inderocro.com
    • Miami, Florida, United States, 33126
      • SKX16B01 Clinical Study - Site 109
      • Contact: Mehria Afzal Pts Recruitment and Site Engagement Specialist, Indero (CRO); Phone Number: 866-575-3111; Email: mafzal@inderocro.com
  • Texas
    • College Station, Texas, United States, 77845
      • SKX16B01 Clinical Study - Site 111
      • Contact: Mehria Afzal Pts Recruitment and Site Engagement Specialist, Indero (CRO); Phone Number: 866-575-3111; Email: mafzal@inderocro.com
    • Houston, Texas, United States, 77027
      • SKX16B01 Clinical Study - Site 119
      • Contact: Mehria Afzal Pts Recruitment and Site Engagement Specialist, Indero (CRO); Phone Number: 866-575-3111; Email: mafzal@inderocro.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Participant is willing to participate and is capable of giving informed consent. Note: Consent must be obtained prior to any study-related procedures.
• Male or female participant of any race aged 18 to 70 years, inclusive, at the time of consent.
• Participants with a clinical diagnosis of DSO, involving 20%-50% of at least one of the great toenails at screening.
• Participants must have no more than 5 toes with suspected presence of onychomycosis (ie, no more than a total of 5 infected toenails, including ≤3 non-great toenails and up to 2 great toenails) at screening.
• Participant's target great toenail must have no involvement of the lunula (matrix) and have ≥ 4 mm of clear (unaffected) nail distal from the proximal nail fold at screening.
• Clinical judgment supports that the historical growth rate of the target great toenail will permit monthly toenail clipping during the study.
• Participant must be willing and able to comply with all study procedures and must be available for the duration of the study.

Exclusion Criteria:

• Participant is a female who is breastfeeding, pregnant, or who is planning to become pregnant during the study.
• Participant has a history or presence of a skin condition on the feet that, in the opinion of the investigator, would interfere with the study assessments.
• Participant is known to have immune deficiency or is immunocompromised.
• Participant has continuous onychomycosis of the toenail(s) for ≥ 5 consecutive years immediately prior to Screening visit without any intervening period of complete resolution (information obtained from medical chart or participant's physician, or directly from the participant).
• Participant has fingernails with suspected presence of onychomycosis.
• Participant has disease involvement confined exclusively to the lateral edge of the target great toenail.
• Participant has "spike" of onychomycosis extending to eponychium of the target great toenail.
• Participant had a major surgery within 8 weeks prior to Day 1 or has a major surgery planned during the study.
• Participant has any clinically significant medical condition or physical/laboratory/vital signs abnormality that would, in the opinion of the investigator, put the participant at undue risk or interfere with interpretation of study results.
• Participant has a known history of chronic infectious disease (eg, hepatitis B, hepatitis C, or human immunodeficiency virus [HIV]).
• Participant has a known history of diabetes and an HbA1C ≥ 8% at screening.
• Participant has reported to have previously failed a standard course of oral antifungal treatment for onychomycosis.
• Participant received prior laser treatment, photodynamic therapy, or chemical or surgical treatment for onychomycosis within the last 12 months prior to Day 1.
• Participant has used any prescription or OTC topical antifungal therapy for the toenails within 4 weeks prior to Day 1.
• Participant has used systemic antifungal therapies within 6 months prior to Day 1.
• Participant has used any topical medicated treatment applied to the feet within 2 weeks prior to Day 1, including but not limited to, anti-inflammatory medications, topical corticosteroids, or topical immunomodulators.
• Participant is currently receiving an investigational product or device for any indication, or has received one within 4 weeks prior to Day 1 (excluding investigational products in trials pertaining to Exclusion Criterion #32).
• Participant is unwilling to refrain from the use of other prescription or OTC onychomycosis treatments, nail cosmetics on their toenails (including nail lacquers), or pedicures from the screening visit until the end of the study.
• Participant has a known or suspected hypersensitivity or allergy to luliconazole or imidazole compounds or the excipients of the formulation.
• Participant has a known history of clinically significant drug or alcohol abuse in the last year prior to Day 1.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Active Arm; SKX-16 (Luliconazole 10% Solution)	Drug: SKX-16 (Luliconazole 10% Solution); Applied topically once daily for 52 weeks to all affected toenails identified by the investigator, followed by a Week 56 follow-up visit.
Placebo Comparator: Vehicle Arm; Vehicle solution that does not contain active ingredients.	Drug: Vehicle solution; Applied topically once daily for 52 weeks to all affected toenails identified by the investigator, followed by a Week 56 follow-up visit, under the same conditions as the active arm.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Complete Cure at Week 56	Proportion of participants who achieve Complete Cure of the target toenail at Week 56, as defined by clinical cure (completely clear target great toenail as assessed by the investigator) and mycological cure (negative KOH microscopy and negative culture)	56 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mycological Cure at Week 56	Proportion of participants with mycological cure (negative KOH microscopy and negative culture) of the target toenail at Week 56	56 weeks
Clinical Cure at Week 56	Proportion of participants with clinical cure (completely clear target great toenail as assessed by the investigator) at Week 56	56 weeks
≤5% Affected Nail Area + Mycological Cure at Week 56	Proportion of participants with ≤ 5% of affected target toenail area and mycological cure of the target toenail at Week 56	56 weeks
<10% Affected Nail Area + Mycological Cure at Week 56	Proportion of participants with < 10% of affected target toenail area and mycological cure of the target toenail at Week 56	56 weeks
Percent Change in Affected Nail Area	Percent change from baseline in percentage of affected target toenail area at Week 56	Baseline and Week 56
Clear Nail Growth at Week 56	Clear nail growth of the target toenail at Week 56	56 weeks

Collaborators and Investigators

• Sponsor: SATO Pharmaceutical Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Estimated): November 24, 2026
• Primary Completion (Estimated): September 23, 2028
• Study Completion (Estimated): October 21, 2028

Study Registration Dates

• First Submitted: October 15, 2026
• First Submitted That Met QC Criteria: November 5, 2026
• First Posted (Actual): November 10, 2026

Study Record Updates

• Last Update Posted (Actual): November 10, 2026
• Last Update Submitted That Met QC Criteria: November 5, 2026
• Last Verified: November 1, 2026

More Information

Terms related to this study

• Keywords: Onychomycosis
• Additional Relevant MeSH Terms: Infections; Skin Diseases; Bacterial Infections and Mycoses; Skin Diseases, Infectious; Nail Diseases; Mycoses; Dermatomycoses; Tinea; Skin and Connective Tissue Diseases; Onychomycosis; Pharmaceutical Preparations; Solutions; luliconazole
• Other Study ID Numbers: SKX16B01

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No