The US Supreme Court has agreed to hear two patent cases that could extend the rights of licensees to challenge patent validity.

The February 21 decision concerns MedImmune v Genentech and MedImmune, v Centocor. In both cases the plaintiff MedImmune challenges the validity of patents, being unhappy with the licence arrangements, using Lear v Adkins (1969) as a precedent.

But unlike Lear, the plaintiff in this case continued to pay royalties under the patent licence, a distinction which led to both cases being dismissed by the Central District of California and the Court of Appeals for the Federal Circuit last year.

Federal Circuit Judge Clevenger wrote last year: "Where a plaintiff lacks standing to pursue a patent law claim, as in this case, we have no jurisdiction over the remaining claims and must transfer the case to an appropriate court of appeals."

The success of the patent petitions to the Supreme Court shows that the top US judges see a need to review the country's IP laws.

Harold Wegner, a partner at Foley & Lardner who closely followed the case, said: "Grant of certiorari manifests the urgent need for legislative patent reform. Here, in the two MedImmune cases, the challenger-licensee was thrown out of court in the proceedings below because it continued to pay royalties under the licence, seeking to have his cake and eat it too."

Both sides are likely to argue the appeals around October this year, with a decision expected before June 2007.

Dewey Ballantine represents MedImmune and Latham & Watkins acts for Genentech.

Although the Supreme Court denied cert to AWH v Phillips in the same week, the decision to hear the MedImmune cases ensures that 2006 will be one of the busiest years for patent cases at America's highest legal authority, raising the profile of IP across the country.