A Phase 3 interventional study of 1% OPA-15406 Ointment and 0% OPA-15406 Vehicle in Atopic Dermatitis (AD), sponsored by Otsuka Beijing Research Institute. Completed at 1 site in China. Open to participants aged 15 Years to 70 Years. Per ClinicalTrials.gov, last updated 2025-08-29.
Sponsored by Otsuka Beijing Research Institute (part of Otsuka Holdings Co., Ltd.) · Phase 3, Interventional, and Treatment
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Among 16 studies testing difamilast in Dermatitis, Atopic — 2 open to participants now, 2 under way, 2 of them phase 3. difamilast · Dermatitis, Atopic.
Among the 16 studies testing difamilast in Dermatitis, Atopic, this one is the 4th largest by enrollment, is one of 2 that started in 2023, is one of 10 in phase 3, and was the 13th registered.
1,592 studies on the registry are indexed under Dermatitis, Atopic; 287 are open to participants now.
Browse Dermatitis, Atopic studies →2 of the 16 studies testing difamilast in Dermatitis, Atopic are open now, in 1 country. Recruiting first, the newest first:
Otsuka Pharmaceutical Co., Ltd. · Sites in Japan
Ages 15–70
Otsuka Pharmaceutical Co., Ltd. · Sites in Japan
Ages 3 mo–14 yrs
By country, each count listing its studies:
difamilast: first FDA approval 2026 (ADQUEY). What it is approved for, and how studies give it, is on its page →
Of the 195 Dermatitis, Atopic studies recruiting now, 83 (43%) set no upper age limit and 96 (49%) stop at 75 or younger; 94 take children under 18; 52 take healthy volunteers.
This study: 15 Years to 70 Years · all sexes · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
16 studies; the count open now beside each. This study's row is marked.
First in 2012; this study’s year is marked. 2 started in 2023.
This study's enrollment of 270 is above the median of 82 across 1,246 interventional studies indexed under Dermatitis, Atopic.
Median enrollment 177 across the 16 interventional studies. Of the 14 that completed or were terminated, 9 (64%) have results posted.
This tab as a report to print or save as PDF → With an account.
16 of 16 have an industry lead sponsor. The 5 most frequent:
This study is registered under Otsuka Beijing Research Institute, one of the names counted as Otsuka Holdings Co., Ltd.. Under that name alone:
Otsuka Beijing Research Institute is the lead sponsor of 36 studies on the registry; none are open to participants now.
13 studies in Dermatitis, Atopic by Otsuka Holdings Co., Ltd.: 2 open now, 2 under way, 2 of them phase 3. Of 11 finished, 8 (73%) have results posted.
Among the 13 studies in Dermatitis, Atopic by Otsuka Holdings Co., Ltd., this one is the 3rd largest by enrollment, is one of 2 that started in 2023, is one of 8 in phase 3, and was the 10th registered.
Otsuka Holdings Co., Ltd.’s Dermatitis, Atopic studies by the year they started, since 2012.
2 of the studies testing difamilast in Dermatitis, Atopic that are under way reach primary completion within a year, 2 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT07173478Phase 3Otsuka Pharmaceutical Co., Ltd.A Phase 3 Trial to Demonstrate the Superiority of 1% OPA-15406 Foam to the Vehicle in Adult Patients With Atopic Dermatitis | 2026-12 |
| NCT07184645Phase 3Otsuka Pharmaceutical Co., Ltd.A Phase 3 Trial of OPA-15406 Foam in Children and Infants With Atopic Dermatitis | 2027-02 |
Add all 2 to your calendar (.ics) → With an account.
Among the 16 studies testing difamilast in Dermatitis, Atopic, from their registry updates:
Nothing recorded among them since 2026-09-25.
Among Otsuka Holdings Co., Ltd.’s 13 in Dermatitis, Atopic:
Nothing recorded among them since 2026-09-25.
This tab as a report to print or save as PDF → With an account.
This is a multinational (China and Korea), multicenter, randomized, double-blind, vehicle-controlled, parallel-group, comparison trial to demonstrate the superiority of 1% OPA-15406 ointment to the vehicle in adult AD subjects.
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:
Subjects with a complication or history of any of the following disorders that the investigator judges would prevent safe conduct of the trial or impact efficacy assessment of the IMP:
Subjects with any of the following hematology or serum chemistry results at screening visit:
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.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
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.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
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.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
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.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The 1% formulation of OPA-15406 ointment will be administered twice-daily (approximately 12 hours apart between morning and night administration) for 4 weeks/24 weeks. The amount of IMP (g) per dose is 10 g/m2 BSA and calculated.
Drug: 1% OPA-15406 Ointment
The vehicle of OPA-15406 vehicle will be administered twice-daily (approximately 12 hours apart between morning and night administration) for 4 weeks/24 weeks. The amount of IMP (g) per dose is 10 g/m2 BSA and calculated.
Other: 0% OPA-15406 Vehicle
Twice-daily administration for 4 weeks/24 weeks.
Also known as: 0% OPA-15406 Vehicle
Twice-daily administration for 4 weeks/24 weeks.
Success rate in Investigator's Global Assessment at Week 4
Investigator's Global Assessment measures the severity of atopic dermatitis (0 = Clear; 1 = Almost clear; 2 = Mild disease; 3 = Moderate disease; 4 = Severe disease/Very severe disease) of clinical characteristics (erythema, infiltration, papulation, oozing, and crusting). A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by the percentage of subjects with Investigator's Global Assessment score of 0 or 1 with improvement by at least 2 grades. Subjects with missing Investigator's Global Assessment data will be handled as non-responders.
Time frame: 4 weeks
Change from baseline in Investigator's Global Assessment at Week 4
Investigator's Global Assessment measures the severity of atopic dermatitis (0 = Clear; 1 = Almost clear; 2 = Mild disease; 3 = Moderate disease; 4 = Severe disease/Very severe disease) of clinical characteristics (erythema, infiltration, papulation, oozing, and crusting). A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by the change from baseline in Investigator's Global Assessment at Week 4.
Time frame: 4 weeks
Success rate in Eczema Area and Severity Index 75 (improvement of ≥75% in Eczema Area and Severity Index) and at Week 4
Eczema Area and Severity Index measures the severity of skin symptoms. The maximum Eczema Area and Severity Index score is 72 points. A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by the success rate in Eczema Area and Severity Index 75 (improvement of ≥75% in Eczema Area and Severity Index) at Week 4.
Time frame: 4 weeks
Eczema Area and Severity Index 90 (improvement of ≥90% in Eczema Area and Severity Index) at week 4
Eczema Area and Severity Index measures the severity of skin symptoms. The maximum Eczema Area and Severity Index score is 72 points. A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by success rate in Eczema Area and Severity Index 90 (improvement of ≥90% in Eczema Area and Severity Index) and at Week 4.
Time frame: 4 weeks
Eczema Area and Severity Index 50 (improvement of ≥50% in Eczema Area and Severity Index) at week 4
Eczema Area and Severity Index measures the severity of skin symptoms. The maximum Eczema Area and Severity Index score is 72 points. A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by success rate in Eczema Area and Severity Index 50 (improvement of ≥50% in Eczema Area and Severity Index) and at Week 4.
Time frame: 4 weeks
Change from baseline in the total score of Eczema Area and Severity Index and each clinical sign score at Week 4
Eczema Area and Severity Index measures the severity of skin symptoms. The maximum Eczema Area and Severity Index score is 72 points. A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by change from baseline in the total score of Eczema Area and Severity Index and each clinical sign score at Week 4.
Time frame: 4 weeks
Change from baseline in Verbal Rating Scale for Pruritus at Week 4
The Verbal Rating Scale measures the intense pruritus in the past 24 hours following Verbal Rating Scale criteria( 0: None,1: Mild, 2: Moderate, 3: Severe). A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by Change from baseline in Verbal Rating Scale (VRS) for Pruritus at Week 4
Time frame: 4 weeks
Change from baseline in Verbal Rating Scale for pruritus up to Day 7
The Verbal Rating Scale measures the intense pruritus in the past 24 hours following Verbal Rating Scale criteria( 0: None,1: Mild, 2: Moderate, 3: Severe). A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's/subjects' judgment. The efficacy is assessed by Change from baseline in Verbal Rating Scale for Pruritus up to day 7.
Time frame: 7 Days
Change from baseline in the total score of Patient-Oriented Eczema Measure at Week 4
Eczema will be evaluated according to Patient-Oriented Eczema Measure .The subjects will answer 7 questions and describe their eczema. The investigator will confirm their responses and record the results in the source document and CRF. The total score of POEM is 28 points at the most. A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by Change from baseline in the total score of Patient-Oriented Eczema Measure at Week 4
Time frame: 4 weeks
Change from baseline in the total score of Dermatology Life Quality Index at week 4
The effects of symptoms on daily life will be evaluated according to Dermatology Life Quality Index (.The subjects will answer a total of 10 questions and describe the effects of the symptoms on their daily life (scale: symptoms, emotions, and functioning). A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by change from baseline in the total score of Dermatology Life Quality Index at week 4.
Time frame: 4 weeks
Change from baseline in the total affected Body Surface Area (percent) at Week 4
The efficacy is assessed by change from baseline in the total affected Body Surface Area (percent) at Week 4.
Time frame: 4 weeks
Success rate in Investigator's Global Assessment at Week 24
Investigator's Global Assessment measures the severity of atopic dermatitis (0 = Clear; 1 = Almost clear; 2 = Mild disease; 3 = Moderate disease; 4 = Severe disease/Very severe disease) of clinical characteristics (erythema, infiltration, papulation, oozing, and crusting). A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by the percentage of subjects with Investigator's Global Assessment score of 0 or 1 with improvement by at least 2 grades. Subjects with missing Investigator's Global Assessment data will be handled as non-responders.
Time frame: 24 weeks
Time to IGA response
How long the subject's Investigator's Global Assessment score (IGA score of 0 or 1) improvement by at least 2 grades will take;
Time frame: 24 weeks
Success rate in EASI 75 (improvement of≥ 75% in EASI), EASI 90 (improvement of≥ 90% in EASI) and EASI 50 (improvement of≥ 50% in EASI)
Eczema Area and Severity Index measures the severity of skin symptoms. The maximum Eczema Area and Severity Index score is 72 points. A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by the success rate in Eczema Area and Severity Index 75 (improvement of ≥75% in Eczema Area and Severity Index) , Eczema Area and Severity Index 90 (improvement of ≥90% in Eczema Area and Severity Index), Eczema Area and Severity Index 500 (improvement of ≥50% in Eczema Area and Severity Index) at Week 24.
Time frame: 24 weeks
Changes from baseline in IGA score
Investigator's Global Assessment measures the severity of atopic dermatitis (0 = Clear; 1 = Almost clear; 2 = Mild disease; 3 = Moderate disease; 4 = Severe disease/Very severe disease) of clinical characteristics (erythema, infiltration, papulation, oozing, and crusting). A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by the change from baseline in Investigator's Global Assessment at Week 24.
Time frame: 24 weeks
Changes from baseline in the total score of EASI and each clinical sign score
Eczema Area and Severity Index measures the severity of skin symptoms. The maximum Eczema Area and Severity Index score is 72 points. A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by change from baseline in the total score of Eczema Area and Severity Index and each clinical sign score at Week 24.
Time frame: 24 weeks
Changes from baseline in the total score of Patient-Orientaed Eczema Measure (POEM)
Eczema will be evaluated according to Patient-Oriented Eczema Measure .The subjects will answer 7 questions and describe their eczema. The investigator will confirm their responses and record the results in the source document and CRF. The total score of POEM is 28 points at the most. A higher score represents a severer clinical impression on the patient's severity based on investigator/clinician's judgment. The efficacy is assessed by Change from baseline in the total score of Patient-Oriented Eczema Measure at Week 24
Time frame: 24 weeks
Changes from baseline in the total affected BSA (%)
The efficacy is assessed by change from baseline in the total affected Body Surface Area (percent) at Week 24.
Time frame: 24 weeks
Adverse events
Adverse events will be examined by frequency, severity, seriousness, discontinuation, and relationship to treatment.
Time frame: 4 weeks/24 weeks
Plasma concentrations of OPA-15406
prior to IMP administration and 2 hours, 4 hours, and 8 hours postdose at Week 4(only in China)
Time frame: Week 4
Clinical laboratory tests
For each parameter (Hematology, Serum chemistry, Urine and/or serum pregnancy for women of childbearing potential), the descriptive statistics will becalculated for measured values and changes from the baseline at each visit for all subjects by treatment group. For qualitative urinalysis values of clinical laboratory tests, a shift table at each visit against the baseline will be created for all subjects.
Time frame: 4 weeks/24 weeks
Vital Signs
The number and percentage of subjects with potential clinical significant changes in body temperature, blood pressure (systolic and diastolic), and pulse rate will be calculated for all subjects.
Time frame: 4 weeks/24 weeks
Body Weigh
For each parameter and body weight, the descriptive statistics will be calculated for measured values and changes from baseline at each visit for all subjects.
Time frame: 4 weeks/24 weeks
Plan to share: No
No publications or documents are linked to this record.
Ran from Feb 2023 to primary completion in Jun 2024, 16 months.
Of 150 industry-sponsored phase 3 interventional studies under Dermatitis, Atopic, half reached primary completion within 18 months of starting (the median), counting those still running; a quarter within 13 and three quarters within 28. This study's 16 months is below that.
Counting every sponsor, half of 157 studies reached it within 18 months; a quarter within 13 and three quarters within 28.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Mar 2025. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Difamilast
Otsuka Beijing Research Institute →