CP-690550 is a potent and selective JAK inhibitor currently in clinical trials for rheumatoid arthritis (RA) and other autoimmune disease indications.  It inhibits recombinant human JAK1 (IC₅₀ ~ 3.2 nM), JAK2 (IC₅₀ ~4.1 nM), and JAK3 (IC₅₀ ~1.6 nM). In cellular assays CP-690550 showed potent effects in the IL-2 blast proliferation assay (IC₅₀ ~11 nM, mediated via JAK1 and JAK3) and HU03 cellular specificity assay (IC₅₀ ~324 nM, mediated via JAK2), but has relatively minimal effects on general cell growth (>10 µM activity in the HFF assay).

How to Use:

• In vitro:  CP-690550 was used at 0.05-1 µM concentration in a panel of in vitro assays.
• In vivo: CP-690550 was orally dosed to rats at 10-50 mg/kg once or twice per day.

Reference:

1. 1.  Flanagan ME, et al. Discovery of CP-690,550: a potent and selective Janus kinase (JAK) inhibitor for the treatment of autoimmune diseases and organ transplant rejection. (2010) J Med Chem. 53(24):8468-84
2. 2.  Meyer DM, et al. Anti-inflammatory activity and neutrophil reductions mediated by the JAK1/JAK3 inhibitor, CP-690,550, in rat adjuvant-induced arthritis. (2010) J Inflamm (Lond).11;7:41.
3. 3.  Ghoreschi K, et al. Modulation of innate and adaptive immune responses by tofacitinib (CP-690,550). (2011) J Immunol. 186(7):4234-43.
4. 4.  Ju W, et al. CP-690,550, a therapeutic agent, inhibits cytokine-mediated Jak3 activation and proliferation of T cells from patients with ATL and HAM/TSP. (2011) Blood. 117(6):1938-46.

Products are for research use only. Not for human use.