Phosphodiesterase-4 Inhibition in Psoriasis

Psoriasis is a chronic immune-mediated inflammatory disorder.Phosphodiesterase-4 (PDE-4) is an enzyme that mediates inflammatory responses and plays a role in psoriasis pathogenesis.PDE-4 degrades its substrate cyclic adenosine monophosphate (cAMP) to adenosine monophosphate (AMP), which subsequently leads to the production of proinflammatory mediators.Inhibitors of PDE-4 work by blocking the degradation of cAMP, which leads to a reduction in inflammation.Apremilast is the only approved oral PDE-4 inhibitor for the treatment of psoriasis.While it is effective for some patients, it may be limited by adverse effects in others.A topical PDE-4 inhibitor, roflumilast, is being investigated in psoriasis and showing promising results.Crisaborole, a topical PDE-4 inhibitor approved for use in atopic dermatitis, has also been investigated in psoriasis.This is an updated comprehensive review to summarize the currently available evidence for the PDE-4 inhibitors apremilast, roflumilast and crisaborole in the treatment of psoriasis, with a focus on data from randomized clinical trials.