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Completed

NCT Number: NCT07244887

Randomized, Triple-Blind, Vehicle-Controlled Trial of Topical Dapsone Gel 7.5% in Patients With Acne Vulgaris

The goal of this randomized, triple-blind, vehicle-controlled clinical trial is to evaluate whether topical 7.5% dapsone gel is effective for treating mild-to-moderate acne vulgaris in adults.

The main questions are:

* Does dapsone gel improve global acne severity compared with a matched vehicle gel? * Does dapsone gel improve comedonal and papulopustular acne severity? * Does dapsone gel reduce erythema and melanin indices measured with a Mexameter, and sebum index measured with a Sebumeter? * Does treatment with dapsone gel improve patients' acne-related quality of life?

Researchers compared once-daily dapsone gel with a matched vehicle gel without the active ingredient.

Participants:

* Applied either dapsone gel or vehicle gel once daily for 8 weeks * Attended clinic visits at baseline, week 4, week 8, and week 12 * Had acne severity assessed using the Global Acne Grading System and Plewig and Kligman comedonal and papulopustular stages * Had erythema and melanin measured with a Mexameter, and sebum measured with a Sebumeter at predefined facial sites * Completed an acne quality-of-life questionnaire at baseline and week 8 * Had standardized photographs taken at each visit

Treatment was continued for 8 weeks, followed by a 4-week treatment-free follow-up through week 12.

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Key information

Conditions

Acne Vulgaris Acneiform Eruptions Erythema Pathological Conditions, Signs and Symptoms Sebaceous Gland Diseases Signs and Symptoms Skin Diseases Skin Manifestations Skin and Connective Tissue Diseases

Age range

18 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Istanbul Training and Research Hospital

Istanbul, 34000, Turkey (Türkiye)

About this study

This is a prospective, randomized, triple-blind, vehicle-controlled clinical trial designed to evaluate the clinical efficacy of topical 7.5% dapsone gel in adults with mild-to-moderate acne vulgaris. The study also investigates the effects of topical dapsone on skin biophysical parameters using standardized instruments: erythema and melanin indices measured with a Mexameter, and sebum index measured with a Sebumeter.

Two parallel arms were included: one group applied topical 7.5% dapsone gel once daily, and the other applied a matched vehicle gel identical in base, tube, and packaging but without the active ingredient. Randomization was performed using a pre-generated computer-based randomization sequence. Participants, dispensing investigators, outcome assessors, and data analysts were blinded to treatment allocation.

Participants attended clinic visits at baseline, week 4, week 8, and week 12. Treatment was applied for 8 weeks, followed by a 4-week treatment-free follow-up period through week 12. At each visit, standardized digital photographs were taken, and acne severity was assessed using the Global Acne Grading System (GAGS), lesion counts used to assign Plewig and Kligman comedonal and papulopustular stages, and standardized clinical evaluation. At each visit, Mexameter readings for erythema and melanin and Sebumeter readings for sebum were obtained at three predefined facial sites: right cheek, left cheek, and forehead. Triplicate measurements were obtained at each site after a standardized acclimatization period. The Turkish-validated Gupta Acne Quality of Life Scale was administered at baseline and week 8.

The primary objective was to determine whether topical 7.5% dapsone gel reduces inflammatory lesion burden compared with matched vehicle at week 8. Secondary evaluations included changes in Global Acne Grading System (GAGS) total score, comedonal acne stage, sebum index, erythema index, melanin index, acne-related quality of life, and local cutaneous adverse events. By combining standardized clinical assessments, patient-reported outcomes, and objective biophysical measurements, this trial aimed to evaluate the clinical and biophysical effects of topical 7.5% dapsone gel in acne vulgaris.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults aged 18 to 50 years with a clinical diagnosis of mild-to-moderate acne vulgaris.
  • No systemic or topical acne treatment within the past 1 month (30 days).
  • Able and willing to provide written informed consent.

Exclusion criteria

  • Pregnancy or breastfeeding.
  • Systemic retinoid or systemic antibiotic use within the past 6 months.
  • Active dermatologic or systemic disease that could interfere with study participation or outcome assessments.
  • Known hypersensitivity to dapsone or any component of the study product.

Treatment and study plan

Dapsone 7.5% gel

Drug

Topical dapsone 7.5% gel applied once daily to the entire face for 8 weeks; route: topical. The study product was supplied in an identical-appearing tube to maintain masking. Participants were followed for 4 weeks after treatment discontinuation.

Other names: topical dapsone 7.5% gel, Vulgarex (country-specific brand)

Vehicle gel

Drug

Vehicle gel without dapsone, identical in base, tube, and packaging to the active product; applied once daily to the entire face for 8 weeks; route: topical. Participants were followed for 4 weeks after treatment discontinuation.

Other names: placebo gel

Primary outcomes

  1. Change in Inflammatory Lesion Count (Papules/Pustules)

    Time frame: Baseline to Week 8 (with interim assessment at Week 4)

    Mean change from baseline in the number of inflammatory facial acne lesions (papules and pustules) per Plewig & Kligman. Blinded dermatologist, standardized facial mapping. Between-group comparison: topical 7.5% dapsone gel vs vehicle/placebo gel.

Secondary outcomes

  1. Change in Global Acne Grading System (GAGS) Total Score

    Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8

    Change from baseline in Global Acne Grading System (GAGS; Doshi et al.) total score. Higher scores indicate more severe acne; a decrease reflects improvement. Between-group comparisons were performed at the end of treatment (week 8) and after the 4-week treatment-free follow-up (week 12).

  2. Change in Plewig and Kligman Comedonal Acne Stage

    Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8

    Change from baseline in comedonal acne stage assigned according to Plewig and Kligman grading. Lower stages indicate less severe comedonal acne; a decrease reflects improvement. Between-group comparisons were performed at the end of treatment (week 8) and after the 4-week treatment-free follow-up (week 12).

  3. Change in Erythema Index (Mexameter)

    Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8

    Change from baseline in facial erythema index measured with a Mexameter at three predefined facial sites: right cheek, left cheek, and forehead. Triplicate readings were obtained at each site after a standardized acclimatization period and averaged per visit. Between-group comparisons were performed at the end of treatment (week 8) and after the 4-week treatment-free follow-up (week 12).

  4. Change in Melanin Index (Mexameter)

    Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8

    Change from baseline in facial melanin index measured with a Mexameter at three predefined facial sites: right cheek, left cheek, and forehead. Triplicate readings were obtained at each site after a standardized acclimatization period and averaged per visit. Between-group comparisons were performed at the end of treatment (week 8) and after the 4-week treatment-free follow-up (week 12).

  5. Change in Sebum Index (Sebumeter)

    Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8

    Change from baseline in facial sebum index measured with a Sebumeter at three predefined facial sites: right cheek, left cheek, and forehead. Triplicate readings were obtained at each site and averaged per visit. Between-group comparisons were performed at the end of treatment (week 8) and after the 4-week treatment-free follow-up (week 12).

  6. Change in Acne Quality of Life Scale (AQOL) Score

    Time frame: Baseline to Week 8

    Change from baseline in Turkish-validated Acne Quality of Life Scale (AQOL) score (Gupta et al). Lower scores indicate better quality of life; a decrease reflects improvement. Between-group comparison.

  7. Incidence and Severity of Local Cutaneous Adverse Events

    Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8

    Number and proportion of participants with treatment-emergent local cutaneous adverse events, including erythema, desquamation, scaling, burning, and tingling, graded for severity and relatedness.

Sponsors and collaborators

Lead sponsor

Oya Helin Dundar

Other Gov

Collaborators

  • Istanbul Training and Research Hospital

Registry information

Official study title

Randomized, Triple-Blind, Vehicle-Controlled Trial Evaluating Clinical Efficacy, Sebum, Erythema, Melanin and Quality-of-Life Outcomes of Topical Dapsone Gel 7.5% in Patients With Acne Vulgaris

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Nov 24, 2025
Registry last updated
May 22, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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