Janus kinase inhibition is promising in the treatment of RA, with already two oral drugs marketed. New compounds are under investigation that are more selective for Janus kinase 1 or Janus kinase 3. Phase II results for filgotinib, upadacitinib, peficitinib and decernotinib are reviewed showing almost consistently a fast dose-dependent clinical improvement similar to already approved drugs tofacitinib and baricitinib. I will reflect on the most frequently reported dose-dependent adverse events and laboratory changes. Some are similar for all drugs of this class, some are more specific for a certain drug, but all may influence future treatment effectiveness in daily practice. This implies the need for a critical evaluation of phase III trials, and eventually trials specifically powered for conclusions on the safety profile and registries once these drugs become marketed. These innovative drugs also need head-to-head trials versus biologics or in-class as well as specific strategy studies to determine their optimal future use.
Keywords: Janus kinase inhibitor; RA; decernotinib; filgotinib; peficitinib; upadacitinib.
© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Rheumatology.