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A question of sulphur

July 2011 - Intellectual Property. Legal Developments by Norrbom Vinding Law Firm, member of ius laboris.

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A large Danish pharmaceutical company was right: A UK patent on an intermediate product it used was invalid.

In the manufacture of chemical drugs, pharmaceutical companies sometimes use what is known as an intermediate product. A large Danish pharmaceutical manufacturer and distributor of anti-depressants used an intermediate product which had been patented by a UK manufacturer. The Danish company therefore went to court to have the patent invalidated in the UK.
The patent covered a process for the manufacture of a substance. One of the steps in the process was adding sulphur to a mixture and then, according to the patent, boiling the mixture in an open reactor which was not pressurised.
But the Danish company did not believe that the patented invention could be said to be novel in relation to a patent application which the Danish company had filed at an earlier point in time. Even if the court disagreed, the patent had to be invalidated anyway for lack of inventive step. For the process had already been described in two scientific articles.
Invalid patent
The UK court sided with the patentee, holding that the patented invention was novel in relation to the Danish company’s own patent application. So the matter had to be decided on the question of inventive step.
The crucial issue here was first of all whether an organic chemist would adjust the amount of sulphur from the level recommended in the articles to the amount specified in the patent. And, secondly, whether prescribing an open and not pressurised reactor involved the necessary inventive step.
The court held that it would have been obvious for an organic chemist to adjust the amount of sulphur to reach the amount specified in the patent. The court also took into account that there was no mention in the patent specification that boiling the sulphuric mixture in an open reactor would have any particular effect. The patented invention therefore lacked inventive step and the patent was invalidated.
Norrbom Vinding notes:
  • that the patent holder and the Danish pharmaceutical company are also involved in other patent proceedings concerning this invention outside the UK; and

  • that the case is a good example of how pharmaceutical companies may try to patent aspects of another company’s product in order to force the other company to ask for a licence.
The above does not constitute legal advice and should not be relied upon as such

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