'Selection' patents invalid unless they make 'plausible' technical contribution, rules High Court

Mr Justice Arnold confirmed previous case law when determining that a drugs company's claim to a class of chemical compounds from a previously known type of compound, a so-called 'selection patent', was invalid.

Mr Justice Arnold said that selection patents are only valid if the pharmaceutical companies that own them can show that there is a plausible link between the compounds covered and the technical contribution claimed by the patent.

The judge said that Idenix Pharmaceuticals had made "stupendously broad" claims in its selection patent that "could well have covered as many as a trillion compounds" but said the company had failed to show that it was at least plausible that substantially all of the compounds claimed had antiviral qualities in line with what was claimed by the patent. Idenix had claimed the patent could help treat Flaviviridae, a family of viruses that can cause diseases including Hepatitis C in humans.

As a result, Idenix had not shown that the selection of individual compounds covered by its patent was justified or credible as "the claimed inventions do not make any technical contribution to the [treatment of Flaviviridae]", Mr Justice Arnold said.

The judge made the finding in a case involving Idenix and a rival drugs manufacturer Gilead Sciences. Idenix had claimed that Gilead had infringed its patent by marketing a new drug called Sovaldi which is used in the treatment of Hepatitis C.

However, its claims were thrown out by Mr Justice Arnold after the judge ruled that the Idenix patent was invalid on a number of grounds including that the invention was not novel.

Mr Justice Arnold came to this finding after determining that Gilead was entitled to claim priority rights from an earlier patent registered in the US and therefore Gilead could use its own patent to attack the novelty of the Idenix’s patent.

To qualify for patent protection inventions must be new, take an inventive step that is not obvious and be useful to industry, as well as satisfy other requirements of patentability.