As promised, Gilead and Galapagos file filgotinib to FDA and get a speedy review

Gilead doubled down on its deal with Galapagos this year with a $5 billion pipeline pact. (Gilead China)

Gilead Sciences emerged from a meeting with the FDA this summer confident it would file for approval in the U.S. by the end of 2019: With just over a week to spare, it’s delivered on that promise.

And not only has it filed its blockbuster arthritis hopeful, it’s done so with a priority review voucher, which should speed things up for Gilead and partner Galapagos.

The drug is already filed in Europe and Japan, but the U.S. market is where the big bucks will come from, making this an important milestone for Gilead, which spent $5 billion on a deep pipeline deal with Galapagos earlier this year.

Gilead has long had a stake in the late-phase JAK1 inhibitor filgotinib, with recent data readouts showing the med is better than methotrexate alone while suggesting it has an edge over AbbVie’s Humira, the aging blockbuster rheumatoid arthritis incumbent.

RELATED: Gilead inks $5B upfront deal to gain broad access to Galapagos' pipeline

Results shared to date suggest Gilead has enough positive evidence to get filgotinib approved. The harder question is whether the evidence is strong enough to get filgotinib a cleaner label than its rivals or otherwise give it an advantage that translates into the hoped-for blockbuster sales.

The safety of filgotinib is a particular source of ongoing uncertainty. Gilead and Galapagos think filgotinib is free from some of the safety problems that blighted Pfizer's Xeljanz and Eli Lilly's Olumiant, which hit multiple members of the JAK family.

However, AbbVie’s Rinvoq, which, like filgotinib, is specific to JAK1, received a black box warning when it won FDA approval earlier this year.

But the filing before 2020 means the drug is still on track; the companies will now have to sit back and wait.