A Patent for Stevia Its Oh So Sweet

What you need to know

• An Australian patent application filed by Coca-Cola and PureCircle covering beverages containing a sweetener composition that includes steviol glycoside Reb X has been accepted.
  
• The patent term will expire in 2032.
  
• A challenge to the patent application on grounds including that the invention claimed was obvious, has failed.
  

What you need to do

• When developing new food and beverage products know that you can sometimes use patents to protect new and inventive formulations, products and manufacturing methods.
• Be aware that others may be seeking to register or may hold patents that can apply to your products and R&D efforts and that these can be infringed even without having knowledge of them.
• Conduct regular watches on competitor patenting activity and obtain freedom to operate advice before progressing product development.
• Consider joint development arrangements, patent licensing and strategic patent oppositions (pre-grant) or re-examination and revocation proceedings (post-grant) to address or clear away problematic patents.

What is Stevia?

Stevia has become a popular zero calorie sweetener as a naturally occurring alternative to sugar. The form of stevia used as a sweetener is derived from the leaves of a plant that is native to parts of South America. While the leaves themselves have been used locally to sweeten drinks for hundreds of years, the commercial stevia product available today is produced by extracting and processing steviol glycosides that are present in the leaves and was only widely approved for use as a food additive from 2008.

There are many different steviol glycosides present in the leaves of the stevia plant but only some of these are approved for use as food additives. The most widely used is Rebaudioside A (Reb A). The glycosides all consist of a steviol molecule linked to a different number of glucose molecules, which results in the glycosides having different degrees of sweetness and taste profiles. Rebaudioside M (Reb M - also known as Reb X) has more glucose molecules which makes it sweeter and less bitter than Reb A. However, Reb X is present is stevia leaves in very low quantities which makes it more expensive to extract and process.

The Patent in Issue

The patent application, no. 2018200689, was filed by Coca-Cola and PureCircle on 30 January 2018. It is a divisional patent application which claims priority from a series of prior patents that have an earliest priority date of 19 December 2011. This is the date at which the newness and inventiveness of the inventions claimed must be assessed.

The primary inventions the subject of the patent include beverages that contain sweetener compositions, in which Reb X is either the sole sweetener or comprises at least 70% by weight of the dry steviol glycoside mixture, or in which there is a mixture of Reb X and Reb A, and which also have a certain sweetness and Reb X concentration.

The opposition

Spicer opposed the grant of the patent on the basis that the claims lacked an inventive step, lacked clarity and lacked utility. These issues had to be assessed by reference to the understanding, skills and knowledge of a hypothetical skilled worker in the relevant field, and the hearing officer decided that this person was a food technologist or beverage formulator, with the relevant field being artificial sweetener compositions.

The hearing officer found that the claims of the patent in essence were "directed to soft drinks (and syrups for making them) having a non-trivial amount of Reb X as the majority steviol glycoside sweetener." He found that the claims were clear and there was no lack of clarity with respect to the requirements of the claims.

Similarly, the hearing officer found that the promises of the claims (as to the amount of Reb X that was useful) were satisfied, and therefore the patent did not lack utility.

Finally, on inventive step (that is, whether the invention was obvious) the hearing officer accepted that the problem to be solved by the invention was an improved low calorie sweetener having a temporal and flavour profile similar to sucrose. The hearing officer accepted that Reb X was known and was an obvious and logical candidate for further investigation and evaluation. However, it was not accepted knowledge in the field that the sweetness profile of any sweetener including Reb X could be predicted from its structure alone, and therefore it was not obvious (expected) that Reb X would solve the identified problem.

Accordingly, Spicer failed on all grounds and the patent has been accepted. At date of writing, Spicer had not sought to appeal the decision but the time to do so had not expired.

Author: Kellech Smith, Partner