Autoimmune diseases, which are of various types and are mostly refractory and serious diseases, are one of the important directions of current drug development. JAK-STAT is one of the few immunomodulatory pathways that has been proven, especially JAK inhibitors. Many drugs, such as tofacitinib, have been marketed worldwide.

The JAK target has been developed for less than 20 years, but currently nearly 7 varieties have been approved for marketing. The indications are mainly tumors and self-immune diseases, and the further refined indications are mainly bone marrow fibrosis and rheumatoid arthritis. The following focuses on the first JAK inhibitor (tofacitinib) for the treatment of rheumatoid arthritis.

Tofacitinib is an oral small molecule JAK inhibitor developed by Pfizer. It has good JAK selectivity. In November 2012, the US FDA approved tofacitinib citrate for the treatment of methotrexate inadequate or intolerant response to treatment. This product is the first JAK inhibitor approved by the FDA for the treatment of rheumatoid arthritis. At present, in addition to the approved indications, tofacitinib is also being tested for its efficacy in ankylosing spondylitis, atopic dermatitis, keratoconjunctivitis sicca and Crohn’s disease. In terms of global sales, the annual sales of tofacitinib in 2017 were more than US$1 billion, and the annual sales in 2019 have reached US$2.242 billion.

Different synthetic routes will have a great impact on the yield and quality of APIs. Our synthesis of tofacitinib citrate avoids the patented route. The synthetic route requires low raw material cost, high yield, single impurities and purity can be controlled within a reasonable range, or can be customized by clients. Thus enable us have obvious advantage on market. Presently our capacity can be 50kg per month, and tofacitinib citrate already exported to USA, Mexico, Franch, Bangladesh, etc.