The Federal Circuit backed up a lower court ruling dismissing an AbbVie lawsuit seeking to invalidate a patent it licensed from MedImmune.

In its complaint, AbbVie asked to have a patent it licensed for its blockbuster drug Humira from Astra Zeneca subsidiary MedImmune thrown out, arguing that a declaration of the patent’s invalidity would mean its royalty obligations to MedImmune had expired in January of this year. The drug made AbbVie more than $16 billion in 2016.

But MedImmune argued that where the suit was filed, the Eastern District of Virginia, lacked jurisdiction to make a declaratory judgment, and that the royalty obligations are tied to the patent’s expiration date in June 2018 regardless of its validity.