Eli Lilly files oral rheumatoid arthritis drug baricitinib in US

Eli Lilly has filed its highly-anticipated rheumatoid arthritis treatment baricitinib in the US, setting the clock ticking on a possible approval later this year.

The orally-active drug is considered a blockbuster contender on the back of clinical trials in which it outperformed AbbVie's Humira (adalimumab), an injectable RA drug that is the world top-selling pharmaceutical with revenues of $13bn in 2014, as well as generic stalwart methotrexate.

The marketing application to the FDA is seeking approval of baricitinib as a once-daily therapy for moderately-to-severely active RA, and prompts a $35m milestone payment from Lilly to Incyte, its development partner for the drug. If approved, Incyte stands to receive another $100m milestone.

Baricitinib is a selective JAK1 and JAK2 inhibitor and if approved will compete with Pfizer's Xeljanz (tofacitinib), currently the only JAK inhibitor approved for use in RA. Pfizer's drug achieved sales of $351m in the first nine months of the year - a 71% rise but still below expectations - as it has been held back by regulatory delays in Europe and the US.

The EMA declined to approve Xeljanz at the first time of asking on concerns of increased infections, while the FDA only gave its blessing to the lower of two submitted doses of the drug and has also resisted approving it for follow-up indications such as psoriasis.

Analysts at Cowen & Co have previously suggested baricitinib has a more favourable clinical profile that could make it a $1.5bn product, with the JAK inhibitor class as a whole capturing around 15% of the $20bn market for RA and psoriatic arthritis drugs.

Other candidates coming through development include AbbVie's ABT-494 and Galapagos/Gilead Sciences' filgotinib, both of which are selective JAK1 inhibitors.

AbbVie was the former partner for filgotinib but handed rights to the drug back to Galapagos after deciding to focus on ABT-494 - which achieved promising results in phase II trials reported last year and has just started a phase III programme. Galapagos - with Gilead as its new partner - is also preparing phase III studies for its candidate.