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Combination of Prior Art In Chemical cases require proof that it is reasonable to combine the documents

Patent Law can be eaten away by intestinal fluke and worm treatments as in the case of Merial Ltd v Norbrook Laboratories Limited [2014] APO 60 (19 August 2014)

Pharmaceutical compositions including veterinary compositions for treatment of parasitic infections in ruminants for example, are a hot bed of patent activity. In a highly research and development driven field, where small changes in a composition may produce large commercial advantages, patents are very valuable assets for protecting such investments.  Equally, it is not surprising that competing companies exercise patent strategies to protect their market share.

In a recent patent opposition hearing handed down in the matter of Merial Ltd v Norbrook Laboratories Limited [2014] APO 60 (19 August 2014), Merial Ltd (the opponent) opposed granting of a patent by Norbrook (the applicant) directed to an anthelmintic composition for treatment of Fasciola hepatica, Ostertagia ostertagi and Cooperia oncophora in ruminants by a topical treatment.

Applicant admitted in background discussion, that treatments using an injection of ivermectin and clorsulon are known. However topical formations are not known.

Applicant claimed a topical (pour-on) composition comprising ivermectin and clorsulon in a carrier comprising alcoholic solvents including two aliphatic alcohols being at least 30% (v/v) of ethanol together with an isopropanol quantity sufficient to 100%”.

The basics

To be patentable we need the claimed invention to be novel compared to prior art.  The invention must also have a difference to the prior art which has an inventive step which is more than an obvious variation.

Prior art (being an earlier published document or earlier prior use) can render a claimed invention not novel if all of the essential features are disclosed in that document or use.

The differences can also be compared to a combination of prior art. This occurs when the differences are an obvious variation or a difference that is part of the “common general knowledge” or a combination of the two.  This common general knowledge could be said to be the standard knowledge including standard library of a person skilled in the art.  It is needed to show in this case that it is reasonable to combine some of the prior art so that you can compare the claimed invention against that combination.  If the difference of the claimed invention to that combination of prior art is not an inventive difference but an obvious variation the claimed invention will not be patentable under the ground of “lack of inventive step”. 

Details of the case.

In this case of Merial Ltd v Norbrook Laboratories, the primary ground relied upon by the opponent was ‘lack of inventive step’ on the basis that:

Common General Knowledge

From evidence it was accepted that it was common general knowledge that:

However, it was not accepted that it was common general knowledge

Difference to first document

A first prior art document WO 02/09764 (the Razzak patent) disclosed a range of active agents that can be combined, and this range includes ivermectin and clorsulon. The solvent system however did not utilise either ethanol or isopropanol.

The critical issue is whether it would have been a matter of routine to alter the composition of Example 5 to use a solvent of ethanol and isopropanol.

It was concluded that the evidence did not establish that it would have been a matter of routine to use a solvent of at least 30% ethanol in isopropanol. It follows that it has not been established that the claims lack inventive step in the light of Razzak.

Difference to combination

It was argued that a combination of the Razzak patent and WO 2005/007241 (Blakely) renders the invention obvious. Section 7(3) permits an opponent to rely on a combination of any two or more pieces of prior art information if the skilled person could, before the priority date, “be reasonably expected to have … combined” the pieces of information.

The feature that is missing from the Razzak patent is the solvent. Formulation 1 in Blakely discloses the solvent system that is missing from the Razzak patent.

The question is therefore

‘would it have been “reasonably expected” that a person could combine the relevant pieces of information in the two documents?

The evidence led by applicant and opponent on whether or not a person would consider it obvious to combine the teachings of Razzak and Blakely, provide contrary opinions without a rationale for their views.

Decision of the Patent Office

The motivation to combine the information in the Razzak and Blakely documents is that it gives all the integers of the present composition.

However, without the benefit of hindsight it is not apparent on the face of the documents that it would have been reasonably expected that a person could combine the information.

Given that the onus rests on Merial in this opposition, Hearing Office was not satisfied that opponent made a case for combining the teachings.  In particular the Hearing Officer concluded:

  1. The evidence on whether or not a person would consider it obvious to combine the teachings of Razzak and Blakely is the statements made by the declarants. The declarants provide contrary opinions without a rationale for their views. I consider that the motivation to combine the information in the Razzak and Blakely documents is that it gives all the integers of the present composition. However, without the benefit of hindsight it is not apparent on the face of the documents that it would have been reasonably expected that a person could combine the information. Given that the onus rests on Merial in this opposition, I am not satisfied that they have made a case for combining the teachings.

Points to remember

Therefore the Hearing Officer decided:

It is therefore important in Patent Office decisions to extensively prove your case of lack of inventive step.