A Phase 4 interventional study of Dapsone 7.5% gel and Vehicle gel in Acne Vulgaris, sponsored by Oya Helin Dundar. Completed at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 50 Years. Per ClinicalTrials.gov, last updated 2026-05-22.
Sponsored by Oya Helin Dundar · Phase 4, Interventional, and Treatment
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:
Researchers compared once-daily dapsone gel with a matched vehicle gel without the active ingredient.
Participants:
Treatment was continued for 8 weeks, followed by a 4-week treatment-free follow-up through week 12.
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.
790 studies on the registry are indexed under Acne Vulgaris; 93 are open to participants now.
This study's enrollment of 100 is above the median of 70 across 672 interventional studies indexed under Acne Vulgaris.
Browse Acne Vulgaris studies →This is the only study on the registry with Oya Helin Dundar as lead sponsor.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Topical dapsone 7.5% gel applied once daily to the entire face for 8 weeks, followed by a 4-week treatment-free follow-up.
Drug: Dapsone 7.5% gel
Vehicle gel without dapsone, identical in base, tube, and packaging to the active product; applied once daily to the entire face for 8 weeks, followed by a 4-week treatment-free follow-up.
Drug: Vehicle gel
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.
Also known as: topical dapsone 7.5% gel, Vulgarex (country-specific brand)
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.
Also known as: placebo gel
Change in Inflammatory Lesion Count (Papules/Pustules)
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.
Time frame: Baseline to Week 8 (with interim assessment at Week 4)
Change in Global Acne Grading System (GAGS) Total Score
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).
Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8
Change in Plewig and Kligman Comedonal Acne Stage
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).
Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8
Change in Erythema Index (Mexameter)
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).
Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8
Change in Melanin Index (Mexameter)
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).
Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8
Change in Sebum Index (Sebumeter)
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).
Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8
Change in Acne Quality of Life Scale (AQOL) Score
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.
Time frame: Baseline to Week 8
Incidence and Severity of Local Cutaneous Adverse Events
Number and proportion of participants with treatment-emergent local cutaneous adverse events, including erythema, desquamation, scaling, burning, and tingling, graded for severity and relatedness.
Time frame: Baseline to Week 12, with interim assessments at Week 4 and Week 8
Ran from Jun 2025 to primary completion in Feb 2026, 7 months.
Of 44 phase 4 interventional studies under Acne Vulgaris, half reached primary completion within 11 months of starting (the median), counting those still running; a quarter within 7 and three quarters within 16. This study's 7 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in May 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Dapsone