Is a day coming when drug delivery systems regulated in Australia by the Therapeutic Goods Administration and included on the ARTG may benefit from an extension to their patent term of up to 5 years?

Objective

As pharmaceutical companies are well aware, the Patents Act 1990 (Cth) contains provisions allowing the term of a standard patent to be extended under certain conditions1. The objective of introducing these provisions by amendment in 1998 was to ensure that pharmaceutical patents had an effective patent life after necessary regulatory approvals had been obtained that was more in line with other fields of technology2.

Problem with application

The problem in seeking an extension for drug delivery systems that may have taken a long time to develop, has been satisfying the condition that one or more pharmaceutical substances per se must in substance be disclosed in the complete specification of the patent and in substance fall within the scope of the claim or claims of that specification3.

It is the difficult “per se” limitation which has been the focus of Court decisions in the past, requiring the claim to the pharmaceutical substance to be unqualified by process, temporal or environmental components. A ‘pharmaceutical substance’ is defined to mean a substance (including a mixture or compound of substances) for a therapeutic use involving particular applications4.

Accordingly, claims for a pharmaceutical substance when used, or for use, in a separate drug delivery system will generally not be directed to a pharmaceutical substance per se. The claim in relation to a pharmaceutical substance must be for a new and inventive product alone. On the basis of this reasoning, claims to a container including a spray composition and a nozzle for nasal administration were not capable of extension.5

The Nuvaring

Against this background, a recent Australian Patents Office (APO) decision6 has granted an extension in respect of Nuvaring (Aust R 96229). This product is, in general terms, a vaginal contraceptive ring formed from a thermoplastic polymer core that releases a mixture of steroidal components, and a permeable skin. In the delegate’s view, the fundamental question was whether Nuvaring itself was a substance (including a mixture or compound of substances). If so, the problematic condition would be met.

Although no courts have considered the bracketed phrase it has been the subject of a small number of APO decisions. In considering these decisions the delegate considered that the term “compound”, contrary to its meaning in pure chemistry, contemplated a compound formed by combining elements or parts, or creating a union of parts, not necessarily limited to any particular spatial arrangement7. Giving the term such a broad meaning the delegate warned would not assist developers of medical devices used with a pharmaceutical substance, the provisions only applied to new and inventive substances8.

The delegate concluded that a pharmaceutical substance can include a compound with a controlled spatial configuration if, as a whole, it can still be considered a pharmaceutical ‘substance’. However, the combination of such substance with what would reasonably be considered a separate physical device, layer or structure is excluded and would not be a pharmaceutical substance per se. Obviously this may be a difficult determination to make in practice. The delegate helpfully suggests that the question may be determined by asking whether the characteristics of what is claimed more predominantly lies with it being a substance rather than a substance in combination with a separate integer.

Evidence was accepted in relation to Nuvaring that the steroidal components are mixed with and diffuse through the thermoplastic materials in the core and the skin such that the component parts of the product exhibited a level of integration or interaction that was more characteristic of a pharmaceutical substance.

Is the Day Here?

Developers of drug delivery systems will need to consider on a case by case basis whether the level of integration or interaction between the component parts of a system will satisfy this requirement. It may be that in practice an application for the grant of an extension will be granted only in the clearest of cases.