Tofacitinib (INN) is a drug of the janus kinase (JAK) inhibitor class, discovered and developed by the National Institutes of Health and Pfizer. Tofacitinib is marketed as Xeljanz and Jakvinus.

It is currently approved for the treatment of rheumatoid arthritis (RA) in the United States and other countries.

It has demonstrated effectiveness in the treatment of psoriasis in Phase 3 studies. It is being studied for treatment of inflammatory bowel disease, and other immunological diseases, as well as for the prevention of organ transplant rejection.

Function:

It is an inhibitor of the enzyme janus kinase 1 (JAK1) and janus kinase 3 (JAK 3) , which means that it interferes with the JAK-STAT signaling pathway, which transmits extracellular information into the cell nucleus, influencingDNA transcription.

In a mouse model of established arthritis, tofacitinib rapidly improved disease by inhibiting the production of inflammatory mediators and suppressing STAT1-dependent genes in joint tissue. This efficacy in this disease model correlated with the inhibition of both JAK1 and 3 signaling pathways, suggesting that tofacitinib may exert therapeutic benefit via pathways that are not exclusive to inhibition of JAK3.

Usage:

Rheumatoid arthritis

Phase II clinical trials tested the drug in rheumatoid arthritis patients that had not responded to DMARD therapy. In a tofacitinib monotherapy study, theACR score improved by at least 20% (ACR-20) in 67% of patients versus 25% who received placebo; and a study that combined the drug with methotrexateachieved ACR-20 in 59% of patients versus 35% who received methotrexate alone.

Psoriasis

Tofacitinib is a current investigational drug in psoriasis. Tofacitinib has demonstrated its effectiveness for plaque psoriasis in Phase 3 randomized, controlled trials in comparison to placebo and to etanercept.In particular, a 10 mg twice-daily dose of tofacitinib was shown to be noninferior to etanercept 50 mg subcutaneously twice weekly.

Ulcerative colitis

The phase 3 OCTAVE study of Tofacitinib in ulcerative colitis started in 2012 and completed in 2015.

Vitiligo

In a June 2015 case report, a 53-year-old woman with vitiligo showed noticeable improvement after taking tofacitinib for five months.

Atopic dermatitis

The results of using Tofacitinib in 6 patients with recalcitrant atopic dermatitis was published in the September 2015. All saw improvement in their atopic dermatitis without any adverse events.

 Specification: