Ivax Pharmaceuticals UK Ltd v Akzo Nobel NV

In assessing obviousness, the court must identify the inventive concept, impute the relevant common general knowledge to the skilled person, identify the differences from the state of the art, and ask whether those differences required invention.

Regulatory obstacles to lawful marketing do not make a technically obvious invention non-obvious. Commercial considerations, including the existence of a competing patent, may nevertheless influence which technically obvious route the skilled person would pursue. Information that the skilled person would routinely obtain during pre-formulation may be treated in the same way as common general knowledge. Once the choice of a polymorphous formulation was made, selecting the claimed particle size by routine testing was obvious.

Ivax Pharmaceuticals UK Ltd and Arrow Generics Ltd challenged the validity of Akzo Nobel NV’s patent for an immediate-release pharmaceutical dosage form comprising polymorphous tibolone of a specified mean particle size.

The challenges relied on lack of inventive step under Patents Act 1977. The claimants argued that a skilled formulator would formulate polymorphous tibolone and determine an appropriate particle size to achieve bioequivalence with the marketed product. Akzo relied, among other matters, on the preference for a single crystalline polymorph, regulatory considerations and the alleged technical prejudice against polymorphous mixtures. The central issue was whether the claimed formulation would have been obvious to the skilled person at the priority date.

1. The attacks on the patent succeeded and the patent would, in principle, be revoked. The precise order was left for agreement or further discussion.

2. The conventional four-step approach in Windsurfing International Inc v Tabor Marine (Great Britain) Ltd [1985] RPC 59 was applicable: identify the inventive concept, identify the skilled person’s common general knowledge, identify the differences from the state of the art, and determine whether those differences were obvious.

3. Obstacles to regulatory approval or lawful sale were not relevant obstacles to an obviousness attack. The court distinguished technical obstacles to manufacture from commercial or regulatory obstacles to marketing, following the reasoning in Richardson-Vick’s Inc’s Patent [1997] RPC 888.

4. Commercial considerations could be relevant to the route that a skilled person would pursue. The existence of the monopoly claimed by the earlier patent could therefore encourage consideration of a technically obvious polymorphous formulation. Commercial considerations were not confined to purely technical matters.

5. The skilled formulator would routinely obtain information about the drug being formulated through a pre-formulation brief or literature search. Although that information might not ordinarily be common general knowledge, it was to be treated in the same way where discovering it was part of the skilled person’s ordinary professional routine. The court followed Nutrinova Nutrition Specialties & Food Ingredients GmbH v Scanchem UK Ltd [2001] FSR 42.

6. The preference for a single crystalline polymorph did not amount to a technical prejudice against formulating a polymorphous mixture. Overcoming that preference was therefore not inventive. Once the skilled person chose a polymorphous formulation, determining a particle size providing bioequivalence with the marketed product was routine testing, and the claimed particle sizes were ordinary. The claimed inventive step was consequently obvious.