Abstract
The law of patent construction in the UK has been largely settled since the 2004 House of Lords' decision in Kirin-Amgen which, in confirming purposive construction as the correct approach, ruled out any US-style doctrine of equivalence. It also doubted the utility of the Protocol Questions, despite their regular application by the UK courts and the adoption of similar questions in other EU jurisdictions. The law on file wrapper estoppel, the use of a patent's prosecution history to estop the patentee from arguing a different construction during litigation, has been settled for even longer. The UK courts have felt strongly that it should not be necessary to read the prosecution history in order to determine a patent's scope. Germany and Canada concur with the UK's approach, however, the US courts take the opposite stance with file wrapper estoppel providing a counterbalance to its doctrine of equivalents. Mr Justice Arnold's judgment in Actavis v Eli Lilly has reopened both these issues. Arnold J not only applied the previously defunct Protocol Questions in construing Eli Lilly's Alimta patent but then used the patent's prosecution history in deciding that its claim did not extend to cover Actavis's variant. This comes close to the US approach criticized by Lord Hoffmann in Kirin-Amgen and may lead to a resurrection of the Protocol Questions as a doctrine of equivalence, even if not explicitly recognized as such.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call