[Intracellular targets : current data on effectiveness and safety profile].

Protein kinase inhibitors represent a novel and promising approach to the treatment of rheumatoid arthritis (RA). By targeting intracellular signaling pathways of cytokine-mediated reactions, these substances are able to interfere with critical immune processes that underly the pathology of RA. With tofacitinib, the first Janus kinase (JAK) inhibitor has been approved in the USA, as well as in Switzerland and other countries. Several other substances are currently undergoing phase II or phase III trials.A crucial question that will shape the future of these new drugs is whether they are safe and in particular, whether they are safer than biological therapies. This article provides an overview on current data concerning the efficacy and safety of the most promising substances and discusses the potential future role of intracellular kinase inhibitors.