mm-36 and Dermatitis--Atopic

Atopic dermatitis (AD) is a common chronic relapsing inflammatory skin disease. The pathogenesis of AD is complex and still not fully understood. Despite recent therapeutic developments, the current therapeutic arsenal of AD remains limited and is associated with long-term efficacy and safety issues. Therefore, new topical therapies with different mechanisms of action are required to overcome the limitations of existing treatments. Difamilast is a phosphodiesterase 4 inhibitor currently in phase 3 studies. Difamilast shows antipruritic and anti-inflammatory properties and a rapid onset of action, with significant differences in some parameters from the vehicle within 1 week of treatment. Phase 2 and 3 clinical trials have shown that difamilast ointments are effective and well tolerated in adult and pediatric patients with AD, and are expected to be used for long-term AD treatment. In 2021, difamilast was the first phosphodiesterase 4inhibitor to acquire manufacturing and marketing approval in Japan for the treatment of adult and pediatric patients (2 years of age and older) with AD. This article is a narrative review of the current literature on difamilast in the management of AD.

Topics: Adult; Benzamides; Child; Commerce; Dermatitis, Atopic; Humans; Skin

To investigate the clinical efficacy and safety of topical difamilast in mild-to-moderate atopic dermatitis (AD).. Only randomized controlled trials (RCTs) that compared topical difamilast with vehicle treatment for patients with AD were included. PubMed, Web of Science, Ovid Medline, Cochrane Library, ClinicalTrials.gov and JapicCTI were searched to 10 April 2022.. Five studies enrolling a total of 1009 patients with mild-to-moderate AD were identified. Compared with the topical vehicle, topical difamilast was associated with a significantly higher success rate according to the Investigator's Global Assessment score at week 4 (relative risk, 2.82; 95% confidence interval [CI]: 2.11-3.77). Compared with the vehicle, difamilast was associated with a significant decrease in day 28 eczema area and severity index scores (mean difference [MD], -4.10; 95% CI: -5.32 to -2.87), verbal rating scale scores (MD, -0.51; 95% CI: -0.71 to -0.32), visual analog scale scores (MD, -12.15; 95% CI: -19.70 to -4.61), patient-oriented eczema measure values (MD, -3.99; 95% CI: -4.91 to -3.07), and total affected body surface area (MD, -6.48; 95% CI: -8.09 to -4.87). No difference in treatment-related adverse events was identified.. This meta-analysis suggests that topical difamilast is an effective and safe treatment for mild-to-moderate AD.

Topics: Dermatitis, Atopic; Double-Blind Method; Eczema; Humans; Randomized Controlled Trials as Topic; Severity of Illness Index; Treatment Outcome

Difamilast is a selective phosphodiesterase 4 inhibitor. Phosphodiesterase 4 is involved in cytokine production linked with inflammatory disorders, including atopic dermatitis.. To demonstrate the superiority of difamilast ointment 1% to vehicle in adult Japanese patients with atopic dermatitis.. In this phase 3, randomized, double-blind trial, patients aged 15-70 years with an investigator global assessment score of 2 or 3 received topical difamilast ointment 1% (n = 182) or a vehicle (n = 182) twice daily for 4 weeks.. The success rate in investigator global assessment score at week 4 (primary endpoint)-the percentage of patients achieving an investigator global assessment score of 0 or 1 with ≥2-grade improvement-was significantly higher with 1% difamilast than with the vehicle (38.46% vs 12.64%, respectively, P < .0001). The success rates in ≥50%, ≥75%, and ≥90% improvement in overall eczema area and severity index score at week 4 followed the same trend. Difamilast at 1% provided significant mean percent improvement from baseline in overall eczema area and severity index score versus vehicle from week 1 to 4. Treatment-emergent adverse events were mostly mild or moderate and less frequent with difamilast.. Study treatment was limited to 4 weeks.. Difamilast ointment 1% demonstrated superiority to the vehicle and favorable safety in adult Japanese patients with atopic dermatitis.

Topics: Adult; Benzamides; Dermatitis, Atopic; Double-Blind Method; Eczema; Emollients; Humans; Hyperplasia; Ointments; Phosphodiesterase 4 Inhibitors; Severity of Illness Index; Treatment Outcome

In atopic dermatitis (AD), phosphodiesterase 4 (PDE4) inhibition reduces proinflammatory mediators and cytokines. Difamilast is a new selective PDE4 inhibitor.. To demonstrate the superiority of topical difamilast to vehicle in Japanese paediatric patients with AD.. This was a phase III randomized, double-blind, vehicle-controlled trial. Patients aged 2-14 years with an Investigator Global Assessment (IGA) score of 2 or 3 received difamilast 0·3% (n = 83), difamilast 1% (n = 85) or vehicle (n = 83) ointment twice daily for 4 weeks.. The primary endpoint was the percentage of patients with an IGA score of 0 or 1 with improvement by at least two grades at week 4. The success rates in IGA score at week 4 were 44·6%, 47·1% and 18·1% in the difamilast 0·3%, difamilast 1% and vehicle groups, respectively. Both difamilast groups demonstrated significantly higher success rates in IGA score compared with vehicle at week 4 [difamilast 0·3% (P < 0·001); difamilast 1% (P < 0·001)]. Regarding secondary endpoints, improvements in Eczema Area and Severity Index (EASI; improvement of ≥ 50%, ≥ 75% and ≥ 90% in overall score) at week 4 were significantly higher in patients in the difamilast 0·3% and 1% groups than those in the vehicle group. EASI score in the difamilast 0·3% and 1% groups was significantly reduced compared with that of patients in the vehicle group at week 1. The significant difference between both the difamilast groups and the vehicle groups was maintained from week 1 through to week 4. Most treatment-emergent adverse events were mild or moderate, and no serious events or deaths were reported.. Difamilast 0·3% and 1% ointments are superior to vehicle and well tolerated in Japanese paediatric patients with AD.

Topics: Adolescent; Benzamides; Child; Child, Preschool; Dermatitis, Atopic; Double-Blind Method; Eczema; Humans; Ointments; Phosphodiesterase 4 Inhibitors; Severity of Illness Index; Treatment Outcome

The safety and efficacy of OPA-15406 (international non-proprietary name, difamilast; also referred to as MM36), a new topical, selective phosphodiesterase type-4 inhibitor, in Japanese pediatric patients with atopic dermatitis aged 2-14 years were evaluated in a phase 2, randomized, double-blind, vehicle-controlled, 4-week study. Seventy-three patients were randomized 1:1:1 to receive OPA-15406 0.3%, OPA-15406 1% or vehicle ointment twice daily for 4 weeks. The mean age of patients was similar across treatment groups. No deaths or serious treatment-emergent adverse events were reported; all treatment-emergent adverse events were mild or moderate in severity. The incidence of treatment-emergent adverse events leading to treatment discontinuation was 4.2% (1/24) in the OPA-15406 0.3% group, 4.0% (1/25) in the OPA-15406 1% group and 16.7% (4/24) in the vehicle group, all of which were worsening of atopic dermatitis. Both OPA-15406 groups demonstrated a higher incidence of success in the Investigator Global Assessment score compared with the vehicle group over the 4-week study. The OPA-15406 groups also showed greater improvements from baseline compared with the vehicle group in the Investigator Global Assessment score, Eczema Area and Severity Index overall score and subscale (erythema, induration/papulation, excoriation and lichenification) scores, Visual Analog Scale pruritus score, Patient-Oriented Eczema Measure score, and percentage of affected body surface area over the 4-week study. Topical OPA-15406 twice daily for 4 weeks was considered a safe and effective treatment option in this phase 2 study in pediatric patients with atopic dermatitis, and phase 3 development is currently ongoing.

Topics: Administration, Topical; Adolescent; Anisoles; Benzamides; Child; Child, Preschool; Cyclic Nucleotide Phosphodiesterases, Type 4; Dermatitis, Atopic; Dermatologic Agents; Double-Blind Method; Female; Humans; Male; Nitriles; Ointments; Phosphodiesterase 4 Inhibitors; Treatment Outcome

PDE4 inhibitors are expected to be anti-inflammatory agents based on their mechanism of action, but the application of this drug class is limited by a narrow therapeutic window due to adverse effects associated with gastrointestinal function. Difamilast, a novel selective phosphodiesterase 4 (PDE4) inhibitor, demonstrated significant efficacy without adverse reactions such as nausea and diarrhea in patients with atopic dermatitis (AD) and was recently approved in Japan. In this study, we investigated the pharmacological and pharmacokinetic properties of difamilast to provide nonclinical data to help understand the clinical effects. Difamilast selectively inhibited recombinant human PDE4 activity in assays. The IC

Topics: Animals; Dermatitis, Allergic Contact; Dermatitis, Atopic; Humans; Leukocytes, Mononuclear; Mice; Phosphodiesterase 4 Inhibitors; Rats; Swine; Tumor Necrosis Factor-alpha

Difamilast, a topical phosphodiesterase 4 (PDE4) inhibitor, has been shown to be effective for treating atopic dermatitis (AD), but the molecular mechanism involved is unclear. Since skin barrier dysfunction including reduced expression of filaggrin (FLG) and loricrin (LOR) contributes to AD development, difamilast treatment may be able to improve this dysfunction. PDE4 inhibition increases transcriptional activity of cAMP-responsive element binding protein (CREB). Therefore, we hypothesized that difamilast may affect FLG and LOR expression via CREB in human keratinocytes.. To elucidate the mechanism by which difamilast regulates FLG and LOR expression via CREB in human keratinocytes.. We analyzed normal human epidermal keratinocytes (NHEKs) treated with difamilast.. We observed increases of intracellular cAMP levels and CREB phosphorylation in difamilast (5 μM)-treated NHEKs. Next, we found that difamilast treatment increased mRNA and protein levels of FLG and LOR in NHEKs. Since reduced expression of keratinocyte proline-rich protein (KPRP) is reported to be involved in skin barrier dysfunction in AD, we examined KPRP expression in difamilast-treated NHEKs. We found that difamilast treatment increased mRNA and protein levels of KPRP in NHEKs. Furthermore, KPRP knockdown using siRNA transfection abolished the upregulation of FLG and LOR in difamilast-treated NHEKs. Finally, CREB knockdown canceled the upregulation of FLG, LOR, and KPRP in difamilast-treated NHEKs, indicating that PDE4 inhibition by difamilast treatment positively regulates FLG and LOR expression via the CREB-KPRP axis in NHEKs.. These findings may provide further guidance for therapeutic strategies in the treatment of AD using difamilast.

Topics: Cyclic Nucleotide Phosphodiesterases, Type 4; Dermatitis, Atopic; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Keratinocytes; Proline