The judgement in Cook Biotech Inc v Edwards Lifesciences AG clarifies that where a company files a priority document for a patent with a joint inventor who is not an employee, and the inventor’s interest in the priority document has not been assigned to the company, the company will not be able to claim priority based upon that document. The resulting loss of priority means more prior art becomes available for assessing validity – which increases the chances of the patent being found invalid.
Edwards applied to invalidate Cook’s patent relating to artificial heart valves. The inventors of Cook’s patent were a Cook employee and two researchers not employed by Cook. The international PCT application – which led to the grant of the patent – had a filing date of 2001 and claimed priority from a US patent application filed in 2000. The US application was filed in the names of the three joint inventors, while the PCT application was filed in the name of Cook. However, the interests of the two external inventors were only assigned to Cook two years after the PCT application was filed – but before the patent was granted.
The right to priority
In his ruling, Mr Justice Kitchin held that the right to priority could be enjoyed only by the person who filed the priority document as it was on that date that the right to priority was claimed. In the Cook case, the right to priority belonged to the two external inventors and Cook, through their employee, and not Cook alone. As a consequence, Cook was not entitled to the claimed priority date. This meant that a document published in late 2000 became available as prior art – and this document was found to invalidate Cook’s patent.
This decision has great significance for companies that work with external inventors. Companies will want to secure the rights in inventions generated by an external inventor – whether the inventions are made by the inventor alone or jointly with the company’s employees – and in any priority document for such inventions, before filing any later patent applications claiming priority from that original document.
What are the options?
One way in which a company could ensure that it has the necessary rights is to contract with the external inventor that, in any invention he makes, he assigns his rights to the company. Although the 1977 UK Patents Act does not allow a patent to be assigned under a contract if it does not exist at the time the contract is made, no such restriction applies in relation to the assignment of ‘rights in inventions’. The company will then have the right to apply for a patent for such invention – and to claim priority from the application in relation to patent applications for subsequent inventions, where relevant.
The inclusion of this provision in a contract will not be effective if – as can often happen with large research projects – work has commenced (and the invention has been made) before contracts have been signed. Under Section 7(2) of the 1977 Patents Act, a person is able to apply for a patent on an invention if he is entitled, at the time the invention is made, to the whole of the property in that invention ‘…by virtue of an enforceable term of any agreement entered into with the inventor before the making of the invention’. If an invention is created by an external inventor before the contract with him has been put in place, the company would need to effect a separate assignment of the external inventor’s rights in that invention.
If the external inventor has made an invention and filed a patent application for that invention, a company wishing to claim priority from that application would need to ensure that the external inventor assigns all his rights in that priority document to the company in time for the company to submit its declaration of priority – ie 12 months from the date of filing of the earliest priority document.
Finally, the need to ensure that priority claims are effective should also be borne in mind by companies as part of due diligence when considering whether to purchase – or license – another company’s portfolio of patents, given the significant effect that an invalid priority claim could have on the value of a whole patent family.
Robert Fitt and Catie Reed are associates in the IP Group at Bristows in London