the case of Kirin-Amgen v Hoechst Marion Roussel: The current position, therefore, is that the House of Lords has held that the principle of purposive construction is entirely in accordance with the Protocol to Article 69, but that the Improver questions may not represent the best approach for dealing with every infringement issue. See Kirin-Amgen v Hoechst Marion Roussel. Foreign relevance The Improver decision was cited with approval by the Supreme Court of Canada in its landmark 2000 Free World Trust v Électro Santé Inc decision. The Improver Questions continue to be relevant for the analysis of essentiality under Canadian law. References United Kingdom patent case law Court of Appeal (England and Wales) cases 1989 in case law 1989 in British law