JAK inhibitors function by interfering with the JAK-STAT signaling pathway via blocking the Janus Kinase enzyme family which includes JAK1, JAK2, JAK3 and TYK2. Studies have shown that JAK1 inhibitors positively contribute to the effectiveness of anti-inflammatory therapies. However, the currently available pan-JAK inhibitors, may also inhibit JAK2 kinase, which contribute to the unwanted side-effect of lower hemoglobin, lymphocyte and neutrophil counts that could result in infection. Therefore, a highly selective JAK1 inhibitor may have an improved safety profile while targeting the anti-inflammatory effect. Selective JAK inhibitor is likely to become a benchmark for a new generation of JAK inhibitors in the future.

As an effective immune modulator and anti-inflammatory medicine, JAK inhibitor has proven its efficacy in treating rheumatoid arthritis, psoriasis, psoriatic arthritis and ulcerative colitis. Research into other immuno-inflammatory diseases such as systemic lupus erythematous is ongoing.