A systematic review of clinical and preclinical evidences for Janus kinase inhibitors in large vessel vasculitis

Corticosteroid-sparing disease-modifying anti-rheumatic drugs are an area of active exploration in large vessel vasculitis (LVV), i.e., Takayasu arteritis (TAK) and Giant Cell Arteritis (GCA). The role of Janus kinase (JAK) inhibitors has been recently identified in different inflammatory rheumatic diseases. We conducted a systematic review of the use of JAK inhibitors in LVV across MEDLINE, Scopus, Web of Science, EMBASE, PubMed Central, Cochrane database of controlled trials, clinicaltrials.gov, and major recent international conferences. We identified four cohort studies and ten case reports. The JAK inhibitors used in these studies were tofacitinib, baricitinib, and ruxolitinib. A cohort study in TAK compared 27 patients treated with tofacitinib with 26 others treated with methotrexate, with better clinical outcomes with tofacitinib but similar angiographic stabilization, relapses, corticosteroid-sparing effect, and adverse events in both groups. Most of the other studies favored clinical responses with JAK inhibitors in LVV but with a paucity of data on other outcomes. Most of the included studies were of moderate quality. Evidence from pre-clinical models of LVV as well as limited in vivo data in patients with TAK appears to suggest that JAK inhibition reduces adventitial fibrosis, intimal proliferation, and inflammatory T lymphocyte infiltration in the media as well as reduces resident memory T cells in the vascular wall (which are otherwise resistant to corticosteroids). Ongoing clinical trials of tofacitinib, baricitinib, and upadacitinib in LVV shall help to further clarify the potential promise of JAK inhibitors for LVV (PROSPERO registration number CRD42021273359).