Difamilast

Difamilast (OPA-15406) is a topical, selective and nonsteroidal phosphodiesterase-4 (PDE4) inhibitor with particularly efficient inhibition of subtype B (IC50=11.2 nM). Difamilast can be used for the research of mild to moderate atopic dermatitis (AD)[1][2][3].

Difamilast is a novel atopic dermatitis drug candidate discovered by Otsuka that has phosphodiesterase 4 (PDE4) inhibitory activity. 

Difamilast has particularly efficient inhibition of subtype B (IC50=11.2 nM). It (OPA-15406) improves skin condition in relevant animal models of AD.

PDE4B: 11.2 nM (IC₅₀)

[1] Hanifin JM, et, al. OPA-15406, a novel, topical, nonsteroidal, selective phosphodiesterase-4 (PDE4) inhibitor, in the treatment of adult and adolescent patients with mild to moderate atopic dermatitis (AD): A phase-II randomized, double-blind, placebo-con DOI:10.1016/j.jaad.2016.04.001
[2] Ahluwalia J, et, al. Phosphodiesterase 4 Inhibitor Therapies for Atopic Dermatitis: Progress and Outlook. Drugs. 2017 Sep;77(13):1389-1397. DOI:10.1007/s40265-017-0784-3
[3] Soeberdt M, et, al. Small molecule drugs for the treatment of pruritus in patients with atopic dermatitis. Eur J Pharmacol. 2020 Aug 15;881:173242. DOI:10.1016/j.ejphar.2020.173242