The drug titan is seeking an injunction against the US Patent and Trademark Office (PTO) to stop them implementing the new rules as of 1 November, a GSK spokesperson told Drugresearcher.com. "We believe the changes in place go beyond the authority of the PTO and have the potential to stifle innovation," they said. Under the present system, companies such as GSK submit their patent applications in order to stake their intellectual property claim as soon as possible after the discovery of a potential new drug candidate. These original applications are usually very broad in scope and as more and more information about the candidate comes to light, companies then file continuations and add extra claims to the original application, all which must then be reviewed by the PTO. Currently there is no limit to the number of continuations and claims that firms such as GSK can make. However, under the new rules, first proposed by the PTO in August, companies may only file up to two continuation applications, with up to 25 claims. Should they wish to exceed this quota they must petition the PTO to do so, proving that "the amendment, argument or evidence sought to be entered could not have been submitted during the prosecution of the prior-filed application," as well as pay the agency additional fees. The PTO is reacting to what it sees as a situation getting out of hand, with more and more continuation applications and claims being made by drug companies as the competition within the industry intensifies. According to the PTO the review process is as a result becoming too cumbersome, taking roughly 32 months, and a backlog of 760,000 applications is mounting. If the rules do indeed come into effect as planned, the PTO plans to apply them retrospectively to all pending patent applications. GSK said it has over 100 such filings pending and another 30 filings planned that will be affected.