Lipitor ruling clarifies status of intermediate compounds in pharma patents

The Borgarting Court of Appeal has handed down its ruling in the Lipitor Case  (case ref LB-2006-26148) between Pfizer and Ranbaxy - Lipitor is currently the biggest-selling drug in the world.

Ranbaxy had contended that one of Pfizer’s patents was invalid since the patent specification was not, in Ranbaxy’s view, sufficiently clear to enable the average person skilled in the art to work the invention. The district court was not convinced of this and the patent was upheld as valid. The appeal court, however, found that the challenged patent did not enable a skilled person to prepare crystalline atorvastatine Form I without an unreasonable burden or experimentation.

The patent-in-suit was based on the assumption that a skilled person would have a particular type of crystalline atorvastatine (the active ingredient) available to be able to form amorphous atorvastatine. The patent did not set out how the starting material was to be prepared and, at the time when the application was filed, it was not commercially available either. A so-called ‘sister’ patent had been revoked as invalid by the European Patent Office, a fact to which the appeal court attached some importance.

Pfizer is the owner of three other patents which, it claimed, were infringed by Ranbaxy. Those patents protected certain chemical intermediate compounds, which occurred in the course of preparing the final compound (the active ingredient) according to the method of the patent-in-suit.

It was not disputed that Ranbaxy actually used the intermediate products, but the manufacture occurred in India, where Pfizer had no patent. The question then was whether the importation into Norway of the final product (the active ingredient) constituted an infringement of the patents covering the intermediate products used to prepare the final products. The court considered the patents on the intermediate products to be product claim patents. Since Ranbaxy was importing only the finished products and not the intermediates, it was not infringing Pfizer’s patents in Norway.

Pfizer argued that the patented intermediates should be considered as incorporated or joined to the final product, and that the patent protection therefore covered the combined product. Further, Pfizer claimed that the intermediates constituted an important part of the final product and that the purpose of the intermediates had been achieved. The court thought otherwise and concluded that the intermediate products could not constitute an element or part of the final product. The intermediates did not exist in the final product, because every chemical synthesis process re-forms a chemical compound into another. At the moment a chemical reaction occurs, the starting material ceases to exist. Thus, the starting material is not present in the final product.

The Supreme Court of Norway has refused to grant leave to appeal the case. The Court of Appeal’s judgement is therefore final and binding.