Akebia Therapeutics Inc v Fibrogen, Inc & Astellas [2020] EWHC 866 (Pat)
Patent validity, insufficiency, plausibility, undue burden, conceptual uncertainty, obviousness, patent infringement by equivalence, patent infringement by off-label use
Fibrogen’s patents concerned the use of an enzyme inhibitor to treat various anaemias. The patents fell into two families (A & B) and included claims to classes of and single compounds. Akebia, for whom I acted, sought revocation of the patents on the grounds of insufficiency and obviousness. Astellas (the licensee) counter-sued for infringement. Arnold LJ held that the Family A patents involved inventive step but, to the extent that they covered classes of compounds, were insufficient. He held that the claims to classes of compounds would have been infringed on a literal basis, but dismissed the infringement claim based on equivalence to the single compound. The Family B patents were obvious. There was insufficient threat of infringement of the Family B patents.
The Court of Appeal reversed the findings of insufficiency ([2021] EWCA Civ 1279). The Supreme Court has granted permission to appeal.