Efficacy and safety of PDE4 inhibitor monotherapy in adult patients with atopic dermatitis: a systematic review and meta-analysis.

INTRODUCTION: Atopic dermatitis (AD) is a chronic inflammatory disease. Phosphodiesterase-4 (PDE4) inhibitors have emerged as a potential therapeutic strategy, but their efficacy and safety profile in adult patients requires comprehensive evaluation. AIM: To assess the efficacy and safety of PDE4 inhibitor monotherapy in adult AD patients. METHODS: A systematic literature search was conducted for studies evaluating PDE4 inhibitor monotherapy in adult AD patients. Study quality was assessed using the Newcastle-Ottawa Scale, and statistical analyses were performed using Review Manager 5.3. RESULTS: Five studies were included. Topical PDE4 inhibitors significantly reduced EASI scores within 4 weeks, with MD = -3.77 [-6.92, -0.62] (p < 0.05) and at week 12, with MD = -3.30 [-5.65, -0.95] (p < 0.05). Within 4 weeks, the severity of targeted lesions and percentage change of severity of targeted lesions decreased significantly, with MD = -2.14 [-2.75, -1.53] and MD = -33.71 [-48.08, -19.34] (p < 0.05). Lower risk of treatment-emergent adverse events was shown for topical PDE4 inhibitors with RR = 0.70 [0.51, 0.97] (p < 0.05). Oral PDE4 inhibitors significantly decreased EASI scores at week 4, 8, 12, and over 16 weeks, with MD = -6.29 [-12.47, -0.11]; -8.32 [-15.12, -1.52]; -9.36 [-15.62, -3.10] and -11.02 [-14.84, -7.21], respectively (p < 0.05). Higher systemic adverse events were shown for oral PDE4 inhibitors with RR = 1.41 [1.13, 1.76] (p < 0.05). Sensitivity analyses demonstrated robust results, and funnel plots indicated no significant publication bias. CONCLUSIONS: PDE4 inhibitor monotherapy provides clinically meaningful treatment for adult atopic dermatitis patients. Topical formulations demonstrate rapid symptomatic improvement and favourable tolerance. Oral administration exhibits cumulative efficacy for severe disease but requires careful risk-benefit assessment.