Much of the recent press attention relating to gene patents has focused on a US federal judge's decision to overturn Myriad Genetics' patent on two breast cancer genes, BRCA1 and BRCA2. But around the same time another important ruling was issued.

After almost eight years in the courts, the biotech company Ariad ultimately lost its patent claims relating to cellular pathways that involve the transcription factor NF-kappa B.

The broad patent, granted in 2002 to several universities and licensed to Ariad, hypothesized that three classes of molecules had the capability to reduce NF-kappa B activity (Nat. Med. 8, 1048, 2002). But it did not detail the substances that have such action. The final US Federal Court decision issued in late March reaffirms the requirement of a 'written description' showing that the inventor possessed the claimed invention at the time of filing.

The winner: Eli Lilly headquarters in Indiana. Credit: Eli Lilly and Company

Ariad, of Cambridge, Massachusetts, had taken Eli Lilly to court for infringement with two drugs that tuned down NF-kappa B activity: the osteoporosis treatment Evista and the sepsis drug Xigris. Ariad won in 2007, but Lilly successfully appealed the following year. This latest federal court decision marks the conclusion of Ariad's subsequent appeal.

The court's decision makes patentees' timing crucial, says George Best, partner and intellectual property litigation expert at the law firm Foley and Lardner in Palo Alto, California. Too early and you might not meet the possession requirement, too late and competitors might get there first.

Although the decision is broadly welcomed, the use of the written description requirement is controversial.

“The problem with using written description is that the standard for compliance is entirely amorphous,” says Chris Holman, associate professor of law at the University of Missouri–Kansas City School of Law. It also makes it more difficult and expensive for patent applicants to get adequate patent coverage, he says.

Ariad's sole remaining legal option is a petition to the US Supreme Court, although Holman and Best deem this highly unlikely.

Nevertheless, Harvey Berger, chairman of Ariad, said in a statement that the company is reviewing the ruling “to assess our options in the case.”