Background: Crisaborole ointment 2% is a nonsteroidal phosphodiesterase 4 inhibitor for the treatment of mild-to-moderate atopic dermatitis (AD). The mechanism of action of crisaborole and its effects on lesional measures of disease severity are not yet well defined.
Objective: This phase 2a, single-center, vehicle-controlled, intrapatient study was designed to further characterize the mechanism of action of crisaborole through evaluation of clinical efficacy and changes in skin biomarkers in adults (n = 40) with mild-to-moderate AD.
Methods: Two target lesions were randomized in an intrapatient (1:1) manner to double-blind crisaborole/vehicle applied twice daily for 14 days. Patients then applied crisaborole (open-label) to all affected areas for 28 days. Punch biopsy specimens were collected for biomarker analysis at baseline, day 8 (optional), and day 15.
Results: Crisaborole treatment resulted in early improvement in lesional signs/symptoms versus vehicle, with improvement in pruritus (pruritus numeric rating scale) observed as early as 24 hours after the first application. Crisaborole-treated lesions showed significant percentage improvement from baseline in lesional transcriptomic profile compared with vehicle at day 8 (91.15% vs 36.02%, P < 10-15) that was sustained until day 15 (92.90% vs 49.59%, P < 10-15). Crisaborole significantly modulated key AD biomarkers versus vehicle, including TH2 and TH17/TH22 pathways and epidermal hyperplasia/proliferation. Molecular profiles and epidermal pathology normalized toward nonlesional skin and correlated with clinical changes in lesion severity and barrier function.
Conclusion: Crisaborole reversed biomarker profiles of skin inflammation and barrier function, with associated improvements in clinical efficacy measures, highlighting the therapeutic utility of targeting phosphodiesterase 4 in patients with AD.
Trial registration: ClinicalTrials.gov NCT03233529.
Keywords: Atopic dermatitis; biomarker; crisaborole; gene expression; inflammation; phosphodiesterase 4; pruritus; transcriptome; transepidermal water loss.
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