Drug Update · Dermatology

FDA Approves difamilast for Mild‑Mod AD: 38% IGA Success (Trial 2)

July 16, 2026

FDA approval date

2026-02-12

Indication

Topical treatment of adults and pediatric patients 2 years and older with mild to moderate atopic dermatitis

Approved formulation

Ointment, 1% (ADQUEY)

Clinical Perspective

This approval affects clinicians treating adults and pediatric patients 2 years of age and older with mild to moderate atopic dermatitis by adding topical difamilast (ADQUEY) as an FDA‑approved option for this population ^[1]^[2]. The randomized vehicle‑controlled trial program demonstrated higher rates of IGA success at Week 4 with ADQUEY versus vehicle, supporting topical PDE‑4 inhibition as a therapeutic approach for these patients ^[2]. How ADQUEY will be integrated with existing topical therapies and its longer‑term comparative tolerability in routine practice remain open questions?

Dr. Rohan Gupta · Dermatology

The FDA approved difamilast (ADQUEY) ointment for the topical treatment of adults and pediatric patients 2 years of age and older with mild to moderate atopic dermatitis on 2026-02-12 based on efficacy demonstrated in three randomized, double-blind, vehicle-controlled trials that measured Investigator's Global Assessment (IGA) success at Week 4; Trial 2 reported IGA success of 38% versus 13% with vehicle ^[2].

Clinical Context

Difamilast is a topical phosphodiesterase‑4 (PDE‑4) inhibitor formulated as a 1% ointment (ADQUEY) developed by Acrotech Biopharma Inc. The agent inhibits PDE‑4 with downstream effects on intracellular cyclic AMP and cytokine/chemokine production; the precise pathway mediating clinical benefit in atopic dermatitis is not fully defined in the label ^[1]^[2]. The FDA approval covers adults and pediatric patients aged 2 years and older with mild to moderate atopic dermatitis, expanding the topical therapeutic options available to dermatology clinicians and other prescribers managing pediatric and adult disease ^[1]^[2]. Short-term controlled trials assessed IGA success at Week 4 as the primary endpoint ^[2].

Key Findings

Trial 2 (Japan) showed ADQUEY (difamilast) achieved IGA success of 38% versus 13% with vehicle at Week 4 (ADQUEY N=182; vehicle N=182) ^[2].
Trial 3 (Japan, pediatric 2–14 years) showed ADQUEY achieved IGA success of 47% versus 18% with vehicle at Week 4 (ADQUEY N=85; vehicle N=83) ^[2].
Trial 1 (multinational: United States, Australia, Poland) showed ADQUEY achieved IGA success of 21% versus 3% with vehicle at Week 4 (ADQUEY N=43; vehicle N=37) ^[2].
Across the three randomized, double‑blind, parallel‑group, vehicle‑controlled trials the primary efficacy endpoint was the proportion of subjects achieving IGA success (IGA 0 or 1 with ≥2‑grade improvement from baseline) at Week 4; the trials enrolled subjects with IGA 2 (mild) or 3 (moderate) disease and affected body surface area between ≥5% and ≤40% ^[2].

Safety & Tolerability

Nasopharyngitis was the most common adverse reaction occurring in ≥1% of subjects and more frequently than vehicle in controlled trials ^[1]^[2].
Application site folliculitis ^[1]^[2].
Contact dermatitis ^[1]^[2].
Application site rash ^[1]^[2].
Molluscum contagiosum ^[1]^[2].
Pain leading to discontinuation in open‑label trials ^[1]^[2].
Pruritus leading to discontinuation in open‑label trials ^[1]^[2].
Vesicles leading to discontinuation in open‑label trials ^[1]^[2].
Blistering leading to discontinuation in open‑label trials ^[1]^[2].
Erythema leading to discontinuation in open‑label trials ^[1]^[2].
Burning leading to discontinuation in open‑label trials ^[1]^[2].
Application site swelling reported in postmarketing experience ^[1]^[2].

Study Design

The FDA approval was based on three multicenter, randomized, double‑blind, parallel‑group, vehicle‑controlled trials (Trial 1 [NCT02068352], Trial 2 [NCT03908970], Trial 3 [NCT03911401]) that together treated 612 adult and pediatric subjects with mild to moderate atopic dermatitis; subjects applied ADQUEY or vehicle ointment topically twice daily, and the primary endpoint in all trials was IGA success at Week 4 ^[2]. Clinicians should consult current prescribing information for full dosing guidance. The trials enrolled subjects with baseline IGA of 2 or 3 and affected BSA between ≥5% and ≤40% (face/neck/head/scalp exclusions specified per trial) and prohibited concomitant AD treatments during the double‑blind periods ^[2]. The FDA granted approval for topical difamilast (ADQUEY) ointment, 1% ^[2]^[1].

FAQ

Q1 What is difamilast (ADQUEY) approved for?

ADQUEY (difamilast) ointment is approved for the topical treatment of adults and pediatric patients 2 years of age and older with mild to moderate atopic dermatitis. The FDA approval applies to a 1% ointment formulation applied topically and was granted following randomized, double‑blind, vehicle‑controlled trials measuring IGA success at Week 4. ADQUEY is indicated for patients aged 2 years and older with an Investigator’s Global Assessment of mild or moderate disease.

Q2 How does difamilast (ADQUEY) work?

Difamilast is a phosphodiesterase‑4 (PDE‑4) inhibitor; inhibition of PDE‑4 increases intracellular cyclic AMP and is associated with decreased production of various cytokines and chemokines. The prescribing information states that while PDE‑4 inhibition is the drug’s mechanism, the specific mechanism(s) by which difamilast produces clinical improvement in atopic dermatitis are not fully defined in the label.

Q3 What is the recommended dose of ADQUEY?

ADQUEY ointment, 1%, is applied as a thin layer to affected areas twice daily and rubbed in completely. It is for topical use only and not for ophthalmic, oral, or intravaginal use; patients should wash their hands after application and avoid applying to infected skin. Clinicians should consult current prescribing information for complete dosing guidance.

Q4 What are the most common side effects of ADQUEY?

In controlled trials, the most common adverse reaction occurring in ≥1% of subjects and more frequently than vehicle was nasopharyngitis. Other adverse reactions observed included application site folliculitis, contact dermatitis, application site rash, and molluscum contagiosum; open‑label longer‑term exposure reported application‑site events that led to discontinuation including pain, pruritus, vesicles, blistering, erythema, burning, and contact dermatitis. Postmarketing reports have included application site swelling.

FDA Approves difamilast for Mild‑Mod AD: 38% IGA Success (Trial 2)

FDA Approves difamilast for Mild‑Mod AD: 38% IGA Success (Trial 2)

Clinical Perspective

Clinical Context

Key Findings

Safety & Tolerability

Study Design

FAQ

References

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