Of the JAK inhibitors currently available, tofacitinib (JAK1 and JAK3 inhibitor), baricitinib (JAK1 and JAK2 inhibitor), upadacitinib (JAK1 inhibitor), filgocitinib (JAK 1 inhibitor), and peficitinib (pan-JAK inhibitor) have been widely used in many regions for RA treatment [23–27]. This evidence concerns the gene JAK1 and rheumatoid arthritis.