Baricitinib phosphate

IC50 Value: JAK1 (5.9 nM) and JAK2 (5.7 nM). Baricitinib, also known as INCB028050 or LY3009104, is a selective orally bioavailable JAK1/JAK2 inhibitor with nanomolar potency against JAK1 (5.9 nM) and JAK2 (5.7 nM). in vitro: INCB028050 inhibits intracellular signaling of multiple proinflammatory cytokines including IL-6 and IL-23 at concentrations <50 nM. Significant efficacy, as assessed by improvements in clinical, histologic and radiographic signs of disease, was achieved in the rat adjuvant arthritis model with doses of INCB028050 providing partial and/or periodic inhibition of JAK1/JAK2 and no inhibition of JAK3. in vivo: The efficacy following daily oral administration of INCB028050 was assessed at doses of 1, 3, or 10 mg/kg based on its pharmacokinetic profile in this species. Disease severity was assessed periodically, scoring clinical signs of disease. These doses were based on the PK/PD relationship established with the IL-6 WBA, with the goal of inhibiting JAK1/2 signaling by no more than 50% for half of the day. Relative to vehicle-treated animals, increasing doses of INCB028050 inhibited disease scores by 24% (p < 0.05), 57% (p < 0.01), and 81% (p < 0.01), respectively. Baricitinib preferentially inhibits JAK1 and JAK2, with 10-fold selectivity over Tyk2 and 100-fold over JAK3. The observed effects of GLPG-0634 on the ACR20, albeit in a smaller study, appear to be at least as good as that seen with tofacitinib and superior to that of baricitinib, since baricitinib only moderately affect the ACR20 values in Phase IIa clinical studies. Clinical trial: Baricitinib (LY3009104, INCB28050) against JAK1/JAK2 starting phase IIb for rheumatoid arthritis

USA