The role of targeted synthetic drugs in the treatment of rheumatic diseases: focus on tofacitinib

Abstract

The treatment of immuno-inflammatory rheumatic diseases has advanced significantly in recent decades due to development of biological medications, which, however, are not without some weak points. They include immunogenicity, parenteral administration, and potentially insufficient stability of the composition of the drug. Great hopes are related to a relatively new class of targeted synthetic immunomodulatory drugs, currently represented in rheumatology by JAK kinase inhibitors (tofacitinib, baricitinib, upadacitinib) and phosphodiesterase 4 inhibitor (apremilast). The most actively developed group is JAK inhibitors that influence one of the most important signal pathway of immune system. This family includes 4 subtypes: JAK1, JAK2, JAK3 и tyrosine-kinase2 (TYK2). JAK-kinases selectively aggregate with cytoplasmic domains of different cytokine receptors, activation of which includes intracellular signal pathway JAK-STAT (Signal Transducer and Activator of Transcription). STAT proteins are responsible for transduction of the signals from more than 50 cytokines, hormones and growth factors that regulate key processes of survival, proliferation and differentiation of immune cells. The greatest practical experience achieved on tofacitinib. This medication approved inRussiafor several indications: rheumatoid arthritis, psoriatic arthritis, psoriasis, ulcerative colitis. Clinical trials of III phase of ORAL series in rheumatoid arthritis and OPAL series in psoriatic arthritis showed high efficacy of Tofacitinib in different clinical situations. In Russian strategic trial REMARKA after treatment with Tofacitinib very fast improvement of the signs of activity was observed, 68,8% patients achieved low disease activity or remission at 6th month of follow-up. Russian open multi-center observational study of Tofacitinib in 101 patients with rheumatoid arthritis and insufficient efficacy of basic and biologic drugs showed achievement of low disease activity or remission in 60% patients, as well as significant improvement of quality of life with a very low frequency of withdrawals due to adverse events (less than 2%).