Appeal court applies doctrine of equivalents in lansoprazole case

On 28th April 2008 the Borgarting Court of Appeal rejected ratiopharm’s appeal against a district court ruling that it had infringed Takeda’s Norwegian analogy method patent for preparing therapeutically active pyridine derivatives, including lansoprazole.

An analogy method patent protects a method for the preparation of a compound and affords indirect product protection. Such protection was available to applications filed up to 31st December 1991, as before then product claims could not be filed for pharmaceuticals in Norway.

The patent had expired in 2004, but a supplementary protection certificate was valid until December 2005. On 2nd May 2005 ratiopharm launched a generic lansoprazole compound in Norway.

Wyeth, a licensee of Takeda, brought infringement proceedings against ratiopharm, and on 4th October 2006 the district court ruled against ratiopharm, awarding Wyeth Nkr28.5 million in damages.

The appeal court confirmed this decision. It found that, under Norwegian and EU law, the scope of protection can comprise more than that which follows directly from the wording of the claims. The court stated that the equivalence test comprises three criteria: 

• The product or process in dispute must solve the same problem as the invention of the patent; 
• The modifications that were made must be obvious to the average person skilled in the art; and 
• The product or process in dispute must not belong to the freely available and known art.

In the case at hand, the appeal court had to decide whether it was obvious to the skilled person (with knowledge of the patent), and on the basis of common general knowledge, to try the disputed method to prepare lansoprazole. In reaching its decision, the court considered:

• the extent to which the disputed method deviated from what a skilled person could make of the wording and context of the claims; 
• whether he or she would expect difficulties in trying it; and 
• whether the disputed method entailed advantages over the patent (ie, the literal meaning of the claims).

The court also stated that no specific importance could be given to the fact that the disputed method was protected by a patent (in this case, in Spain), although the grant of a patent may indicate that the method did not come under the scope of other patents.

The appeal court found that there were several differences between the two methods: 

• The starting materials were partially different; 
• The disputed method achieved an oxidation step with a nitro group on the pyridine ring, whereas the patent claim spoke of a “C2-5 fluorized alkyle”; 
• The oxidated compounds comprised different substituents; and 
• The disputed method included the final introduction of the tri-fluor-etoxy group, a step not found anywhere in the patent claims.

Nevertheless, the court appears to have focused more on what the two methods had in common. It also found that there were both advantages and disadvantages into applying the disputed method, compared to the patented method. Although the courts agreed with the rights holder that pioneer inventions may be entitled to wider protection, the court did not find lansoprazole to be a pioneer invention.

The appeal court concluded that it was obvious to the skilled person to try the disputed method, and that he or she would have had a reasonable expectation of success. Thus, infringement had occurred.

Regarding damages, the parties agreed that the losses suffered were Nkr28.5 million. However, the court had to decide whether the infringement had been negligent, since this is a prerequisite for liability. It stated that even if it is difficult to determine the scope of protection of the patent, ratiopharm had taken a calculated risk and was at fault for not having ascertained whether its views could be supported by technical and objective experts.

ratiopharm has appealed the ruling, but it has not yet been decided if the Supreme Court will hear the appeal. The Supreme Court recently refused Sandoz leave to appeal the Court of Appeal judgment in the Sertraline Case (for further details see “Court confirms that equivalents doctrine applies to ‘analogy method’ patents”).