Dermatology and Therapy (Jul 2024)

An Interim Report of a Phase 3, Long-Term, Open-Label Study to Evaluate Efficacy and Safety of Difamilast Ointment in Japanese Infants with Atopic Dermatitis

  • Hidehisa Saeki,
  • Yukihiro Ohya,
  • Naoko Baba,
  • Tomomi Imamura,
  • Daisuke Yokota,
  • Hidetsugu Tsubouchi

DOI
https://doi.org/10.1007/s13555-024-01236-7
Journal volume & issue
Vol. 14, no. 9
pp. 2443 – 2455

Abstract

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Abstract Introduction Difamilast is the first selective phosphodiesterase 4 inhibitor approved for atopic dermatitis (AD) in Japan. A phase 3, 52-week, open-label study is ongoing to establish efficacy and safety of difamilast ointments in infants with AD aged 3 to < 24 months because a clinical study has not been conducted in this population. Methods This study consisted of a 4-week primary evaluation period in which difamilast 0.3% ointment was applied twice daily to Japanese infants aged 3 to < 24 months (n = 41) and an ongoing 48-week long-term extension period in which difamilast 0.3% or 1% ointment was applied based on existing symptoms. The data on efficacy and safety of difamilast were obtained as of an interim report in the study period. Results The response rate in Investigator’s Global Assessment score was 45.0% at week 1, which was maintained at 56.1% at week 4 and 63.4% at the interim report. Infants achieved the response rate in Eczema Area and Severity Index 75 (improvement of ≥ 75%) of 47.5% at week 1, which further improved to 82.9% at week 4 and 78.1% at the interim report. Adverse events (AEs) were reported in 22 (53.7%) infants in the primary evaluation period: of those the most frequent AE was nasopharyngitis (19.5%) followed by dermatitis contact (7.3%). As of the interim report, 36 (87.8%) infants experienced AEs: of those, nasopharyngitis (70.7%) and gastroenteritis (22.0%) were most frequently observed. The total AEs were mostly mild or moderate in severity. No investigational medicinal product-related AEs and no AEs leading to discontinuation were reported. Conclusion Difamilast ointments applied twice daily to Japanese infants with AD aged 3 to < 24 months is effective and well tolerated as of the interim report in the study period. The final results will be reported in the near future. Clinical Trial Registration: Clinical Trials. gov identifier: NCT05372653.

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