Fibrogen v Akebia & Astellas v Akebia [2021] EWCA Civ 1279
Patent validity, insufficiency
This was an appeal of the findings of insufficiency and the obviousness of the Family B patents in the judgment of Arnold LJ ([2020] EWHC 866 (Pat)).
Birss LJ Arnold LJ had construed the claims incorrectly and applied the wrong test. Birss LJ held that the correct approach is to ask whether it is possible to make a reasonable prediction that the invention will work with substantially everything falling within the scope of the claim. In determining the scope of the claim compounds Birss LJ distinguished between two types of functional limitations: those that determine the scope of the claimed class and those that describe the technical effect to be achieved by the claimed compounds. He set out the following three-step approach:
(1) Identify what it is which falls within the scope of the claimed class;
(2) Determine what it means to say that the invention works (i.e. what is it for?);
(3) Answer the question whether it is possible to make a reasonable prediction the invention will work with substantially everything falling within the scope of the claim.
By this approach so-called step 1 functional features define the scope of the claimed compounds which are then assessed for plausibility rather than asking whether all compounds with the claimed structural features will have the claimed functional features. Accordingly Birss LJ found that the claims were not insufficient.
The appeal in respect of the finding that the Family B Patents were obvious was dismissed.
The Supreme Court have granted Akebia permission to appeal. The appeal will be heard in 2024.