Baricitinib, sold under the brand name Olumiant among others, is an immunomodulatory medication used for the treatment of rheumatoid arthritis, alopecia areata, and COVID-19.

[9][12][10] In February 2017, baricitinib was approved for use in the European Union as a second-line therapy for moderate to severe active rheumatoid arthritis in adults, either alone or in combination with methotrexate.

[13][8] In May 2018, the US Food and Drug Administration (FDA) approved baricitinib for the treatment of adults with moderately to severely active rheumatoid arthritis who have had an inadequate response to one or more TNF antagonist therapies.

[2][13] In studies, upper respiratory tract infections and high blood cholesterol levels (hypercholesterolemia) occurred in more than 10% of participants.

In studies, inhibitors of the liver enzymes CYP3A4, CYP2C19, and CYP2C9, as well as the CYP3A4 inducer rifampicin, had no relevant influence on baricitinib concentrations in the bloodstream.

Via a signal transduction pathway involving STAT proteins, this ultimately modulates gene expression in immunological cells.

[10] The primary measurement of efficacy for both trials was the proportion of participants who achieved at least 80% scalp hair coverage at week 36.

According to the paper "mechanistic actions of a Janus kinase-1/2 inhibitor targeting viral entry, replication and the cytokine storm, and is associated with beneficial outcomes including in severely ill elderly people".

[36] The data supporting the US Food and Drug Administration (FDA) emergency use authorization (EUA) for baricitinib combined with remdesivir was based on a randomized, double-blind, placebo-controlled clinical trial (ACTT-2), which was conducted by the US National Institute of Allergy and Infectious Diseases (NIAID).

[37][38] This clinical trial evaluated whether baricitinib impacted how long it took for subjects who were also taking remdesivir to recover from COVID-19.

[37] In November 2020, the World Health Organization (WHO) updated its guideline on therapeutics for COVID-19 to include a conditional recommendation against the use of remdesivir, triggered by results from the WHO Solidarity trial.

[39][40] In November 2020, the FDA issued an emergency use authorization (EUA) for the combination of baricitinib with remdesivir, for the treatment of suspected or laboratory confirmed COVID-19 in hospitalized people aged two years of age or older requiring supplemental oxygen, invasive mechanical ventilation, or extracorporeal membrane oxygenation (ECMO).

[41][42][37] Then in September 2021, the largest randomized, placebo-controlled trial of hospitalized people with COVID-19 to date, COV-BARRIER, was published.

[citation needed] As of April 2021[update], the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) is evaluating the use of baricitinib to include treatment of COVID-19 in hospitalized people from ten years of age who require supplemental oxygen.