The rules were set to take effect on November 1.

The preliminary injunction enjoining the USPTO was issued by the US District Court in Virginia following the October 31 hearing of the consolidated complaints lodged by Triantafyllos Tafas and GlaxoSmithKline (GSK).

Just one day before the USPTO’s final rules on claims and continuations were due to take effect, Judge James Cacheris granted a temporary restraining order and preliminary injunction staying implementation of the rules until the Court has had time to consider the full merits of the case.

The news will be welcomed by many IP practitioners who were concerned about the impact of the new rules on their patenting strategies.

In recent days, the American Intellectual Property Law Association, IBM and representatives of SanDisk have all filed briefs in support of the GSK and Tafas lawsuits.

HEXAS, the Roskamp Institute, Tikvah Therapeutics, the Biotechnology Industry Organization (BIO) and Elan Pharmaceutical have filed motions for leave to file amici curiae briefs in support of GSK’s motion as well.

New York Senator Charles Schumer also openly criticized the rules in his letter to USPTO director Jon Dudas on October 25.

the hearing lasted just over one hour, said Courtenay Brinckerhoff of Foley & Lardner, who attended the proceedings in the Virginia Court.

Brinckerhoff said that after all the arguments had been presented, Judge Cacheris took a 20 minutes break before returning to report that he would grant and issue the preliminary injunction by the end of the day on Wednesday.

Brinckerhoff told MIP Week that those present seemed generally "relieved and amazed" by Judge Cacheris’ decision: "The PTO went on a campaign across the country with the proposed rules saying that they were coming whether we liked it or not. Now we’ve got a chance to fight them."

She said that one of the strongest arguments presented was that the proposed rules are substantive rather than procedural, and that therefore only Congress has the authority to implement them. She also noted that, while the court room was packed with industry representatives supporting GSK, there did not appear to be anyone present in support of the PTO.

In a statement issued after the ruling, a spokesperson for the USPTO said that the continuations rules are part of a package of initiatives "designed to improve the quality and efficiency of the patent process and move American innovation and our economy forward".

"Interest shown by the US Supreme Court and the US Congress in patent modernization indicates that the system needs change. The USPTO continues to believe that the rules are an important component of modernizing the patent system," it said.

Short of the PTO withdrawing the rules completely or appealing the decision, the injunction will remain effective until the Court has issued a final decision on the merits of the case, which is likely to be sometime between late December and early January.

The USPTO posted a notice on its website explaining that employees are to continue processing and examining patent applications under the rules and procedures in effect on October 31 2007 until further notice.

Steven Moore of Kelley Drye & Warren, who is representing Triantafyllos Tafas, told MIP Week that it is unlikely that the PTO will back down completely following yesterday’s ruling. "From what I’m hearing [the PTO] is maintaining its position that these rules are good and they’re going to fight", said Moore.

The PTO has filed a motion to dismiss Tafas’ suit, which Moore said will be heard next Friday.

Regarding the decision, Moore said: "It was a godsend that [GSK] came in, because this one little guy couldn’t have done it on his own. Needless to say, we are happy."

Nancy Pekarek, vice-president of corporate communications for GSK, told MIP Week: "We’re pleased that the Court has determined there’s a need to review these rules before they go into effect. The legal question presented is whether [the PTO] has the authority to do this under the Patent Act – we feel that they do not because these rule changes are substantive rather than procedural. It’s great that others are joining in – it’s not just a GSK issue, it will affect everyone filing for patents."

Although a briefing schedule for summary judgment is still being negotiated, John Desmairis, counsel for GSK, said that the next hearing is likely to take place between February and April of 2008.

Meanwhile, Triantafyllos Tafas, the inventor who is also suing the PTO, has served both director Jon Dudas and deputy director John Doll with notices requiring that they appear for a deposition at the offices of Kelley Drye & Warren in Washington DC on December 7 2007.

PLI blog editor, Gene Quinn of White & Quinn, wrote: "I personally think that these results demonstrate what most in the industry would expect. It was the right call to enter a preliminary injunction and while that always means that there is a likelihood of success on the merits, ultimate success is not guaranteed."