In vitro profiling of rheumatic-disease-evaluated JAK inhibitors demonstrate differences in JAK isoform selectivity between different types of inhibitors.

Inhibition of JAK kinase activity did not directly translate into cellular inhibition of JAK-STAT signaling. Despite differences in JAK-selectivity, the cytokine inhibition profiles of currently approved JAKinibs were highly similar with preference for JAK1-mediated cytokines. Novel types of JAKinibs showed narrow cytokine inhibition profile specific for JAK3- or TYK2-mediated signaling. This article is protected by copyright. All rights reserved.