Phase III trials of JAK1 selective inhibitors in rheumatoid arthritis.

Upadacitinib and filgotinib, two JAK1 selective drugs have undergone extensive phase III clinical trials in RA and have demonstrated rapid improvements in disease activity, function and patient reported outcomes. Six global phase III randomized controlled clinical trials (SELECT phase III program) evaluated the efficacy and safety of upadacitinib and four clinical phase III trials (the FINCH program) evaluated the efficacy and safety of filgotinib. This article is a critical review of all these studies with focus on the therapeutic efficacy in RA. The aim is to display the data that could allow the approval of these new drugs for the treatment of RA (upadacitinib has been already approved in most of the markets around the world).