Plaque psoriasis is a chronic and often debilitating skin disorder and proinflammatory cytokines are known to play a key role in the disease process.To evaluate the safety and efficacy of baricitinib, an oral Janus kinase (JAK) 1/JAK2 inhibitor, in patients with moderate-to-severe psoriasis in a randomized, double-blind, placebo-controlled, dose-ranging phase 2b study.Patients were randomized (n = 271) to receive placebo or oral baricitinib at 2, 4, 8 or 10 mg once daily for 12 weeks (Part A). Dose adjustment for 12 additional weeks was based on percentage improvement in the Psoriasis Area and Severity Index (PASI) score. The primary end point was Psoriasis Area and Severity Index (PASI) 75% (PASI-75) at 12 weeks for North American patients (n = 238); secondary end points were safety and efficacy measures in the entire population.At week 12, more North American patients in the 8-mg (43%) and 10-mg (54%) baricitinib groups than in placebo group (17%; P < 0·05) achieved PASI-75. All baricitinib-treated groups had greater mean changes from baseline in their PASI scores (P < 0·05) at 12 weeks and (except 2 mg) had higher rates of PASI-50 than the placebo group; statistically significant PASI-90 responses were achieved in the 8-mg and 10-mg groups at 8 and 12 weeks. More than 81% of PASI-75 responders maintained their scores through 24 weeks. During Part A, study discontinuations due to adverse events (AEs) were 0%, 0%, 2·8%, 6·3% and 5·8% and treatment-emergent AE rates were 44%, 50%, 47%, 58% and 64% for placebo and 2-, 4-, 8- and 10-mg baricitinib groups, respectively. No opportunistic infections were observed in any treatment group. Dose-dependent changes in laboratory values were observed.Patients with moderate-to-severe psoriasis treated with baricitinib for 12 weeks achieved significant improvements in PASI-75.© 2016 The Authors. British Journal of Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists.

Baricitinib (Olumiant) is an oral, targeted synthetic DMARD that inhibits JAK1 and JAK2, which are implicated in the pathogenesis of rheumatoid arthritis (RA). This novel, small molecule is approved for use as monotherapy, or in combination with methotrexate, for the treatment of adults with moderate to severe active RA who responded inadequately to or were intolerant of ≥ 1 DMARD. In pivotal multinational trials, once-daily baricitinib 4 mg, with/without methotrexate (± another csDMARD), improved the signs and symptoms of RA, disease activity and physical function in DMARD-naive patients and in patients with an inadequate response to methotrexate, csDMARDs or TNF inhibitors; baricitinib treatment also slowed structural joint damage in DMARD-naive patients and in those with an inadequate response to methotrexate and csDMARDs. Baricitinib plus methotrexate was more effective than adalimumab plus methotrexate in patients with an inadequate response to methotrexate. The onset of these benefits was generally rapid and sustained over time. Baricitinib was generally well tolerated during up to 5.5 years' treatment; the most commonly reported adverse drug reactions were upper respiratory tract infections, increased LDL cholesterol, nausea and thrombocytosis. Thus, once-daily baricitinib, as monotherapy or in combination with methotrexate, is an effective and generally well tolerated emerging treatment for patients with moderate to severe active RA who have responded inadequately to or are intolerant of ≥ 1 DMARD, and extends the options available for this population.

Baricitinib (Olumiant™) is an orally-administered, small-molecule, janus-associated kinase (JAK) inhibitor developed by Eli Lilly and Incyte Corporation for the treatment of rheumatoid arthritis (RA), atopic dermatitis and systemic lupus erythematosus. JAKs transduce intracellular signals from cell surface receptors for various cytokines and growth factors involved in inflammation and immune function, suggesting JAK inhibitors may be of therapeutic benefit in inflammatory conditions. In February 2017, baricitinib was approved in the EU, as monotherapy or in combination with methotrexate, for the treatment of moderate to severe active rheumatoid arthritis in adult patients who have responded inadequately to, or who are intolerant to one or more disease-modifying anti-rheumatic drugs (DMARDs). Regulatory approval to market baricitinib as a treatment for RA has also been sought in the USA and Japan. This article summarizes the milestones in the development of baricitinib leading to this first global approval for the treatment for moderate to severe active RA in adult patients who have responded inadequately to, or are intolerant to one or more DMARDs.

A highly efficient method for the synthesis of baricitinib was developed. The starting material tert-butyl 3-oxoazetidine-1-carboxylate was converted to intermediate 2-(1-(ethylsulfonyl)azetidin-3-ylidene)acetonitrile via the Horner–Emmons reaction, deprotection of the N-Boc-group and a final sulfonamidation reaction. Then the nucleophilic addition reaction was carried out smoothly to afford the borate intermediate in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene under reflux. Finally, the desired compound baricitinib was obtained by the Suzuki coupling reaction of 4-chloro-7- H-pyrrolo[2,3- d]pyrimidine with the above borate intermediate. All compounds were characterised by IR, MS, 1H NMR and 13C NMR. The overall yield in this synthetic route was as high as 49%. Moreover, this procedure is straightforward to carry out, has low cost and is suitable for industrial production.