Doramapimod

Doramapimod (BIRB 796) is an orally active, highly potent p38 MAPK inhibitor, which has an IC₅₀ for p38α=38 nM, for p38β=65 nM, for p38γ=200 nM, and for p38δ=520 nM. Doramapimod has picomolar affinity for p38 kinase (K_d=0.1 nM). Doramapimod also inhibits B-Raf with an IC₅₀ of 83 nM^[1][2]. IC50 & Target:IC50: 4 nM (p38α), 83 nM (B-Raf)^[1] In Vitro: Doramapimod (BIRB 796) is usually associated with inflammation because of its role in T-cell proliferation and cytokine production^[1].
Doramapimod (BIRB 796) blocks the stress-induced phosphorylation of the scaffold protein SAP97, further establishing that this is a physiological substrate of SAPK3/p38γ. The binding of Doramapimod to the p38 MAPKs or JNK1/2 is impairing their phosphorylation by the upstream kinase MKK6 or MKK4^[3]. In Vivo: The mean xenograft weigh of Doramapimod (BIRB 796) is lighter than control. The inhibition rate of Doramapimod is 1.93%^[4].
The Doramapimod (BIRB 796) treatment slightly reduces blood pressure (166±7 mm Hg at week 7; P<0.05), whereas SD rats are normotensive (123±3 mm Hg). Despite the reduction in blood pressure, untreated and Doramapimod-treated dTGRs have similar heart weight and cardiac hypertrophy indices (heart-to-tibia ratio), which are significantly higher compare with nontransgenic SD rats (310±6 versus 307±6 versus 206±5 mg/cm, respectively; P<0.05)^[5].