In its lawsuit, filed on Thursday, GSK requests the judge to "preliminarily and permanently enjoin the PTO from implementing the Final Rules" relating to claims and continuations.

A copy of the complaint obtained by www.ipwatchdog.com shows that GSK has dubbed the rules "vague, arbitrary and capricious," and asserts that they will "prevent GSK from fully prosecuting patent applications and obtaining patents on one or more of its inventions".

The lawsuit is the second that has been filed against the USPTO and its director Jon Dudas regarding the new rules, which place controversial limits on the number of continuations and claims that a patent applicant can file.

In August, MIP Week reported on a similar complaint filed by individual inventor Triantafyllos Tafas, which alleged that the PTO "exceeded its congressionally-delegated rulemaking authority and that the new rules violate numerous sections of the Patent Act".

In a statement, Kelley Drye & Warren, the law firm representing Tafas, said that the inventor has described the new rules as "designed to crush the ability of the small inventor and small emerging companies to effectively pursue patent rights and protections".

The November issue of Managing IP will carry a full-length feature about the criticism that the USPTO faces, and how it is responding.