US regulators have extended the review period for Eli Lilly and Incyte's baricitinib, a once-daily oral medicine submitted in January last year for the treatment of moderate to severe rheumatoid arthritis.

The US Food and Drug Administration has extended the action date by three months to allow it to review additional data analyses recently submitted by Lilly - which the regulator considers a major amendment - in response to its request for more information.

J. Anthony Ware, senior vice president, product development and interim president of Lilly Bio-Medicines, "said the firm will "continue to work closely with the FDA throughout the review process," and believes "baricitinib has the potential to be an effective treatment choice, especially for those patients for whom current therapies are not adequately addressing their disease".

Baricitinib is a once-daily oral JAK inhibitor currently in clinical studies for inflammatory and autoimmune diseases. JAK-dependent cytokines have been implicated in the development of a number of inflammatory and autoimmune diseases, so it is hoped that JAK inhibitors could be effective in treating a wide range of inflammatory conditions.

Data from the Phase III RA-BEAM study, published in 2015, showed that the drug scored significantly better than placebo on the ACR20 response, a standard clinical measure that represents at least a 20 percent, and also hit the secondary target of showing superiority to AbbVie's multi-billion-dollar blockbuster Humira (adalimumab).

Over in Europe, the European Medicines Agency's (EMA) Committee for Medicinal Products for Human Use (CHMP) recommended approval of baricitinib - which is to be marketed as Olumiant - for the treatment of RA in December 2016.

The drug is also being assessed in Phase II trials for atopic dermatitis and systemic lupus erythematosus, and a Phase III trial for patients with psoriatic arthritis is expected to be initiated sometime this year.