Canada has a legislative scheme — the Patented Medicines (Notice of Compliance) Regulations (“Regulations”) — that links drug regulatory approval to patent protection. If the Regulations are engaged, a pharmaceutical patentee may delay regulatory approval for a second party (usually a generic) to sell the patentee’s medicine, sometimes for as long as the life of its patents. This is particularly important in Canada, where interlocutory relief in a patent infringement action is almost impossible to obtain, and where data protection legislation (which can also delay generic market entry) has been found only to apply in limited situations.
In order to benefit from the Regulations, a patent must be listed on the Patent Register maintained by the Minister of Health. A patent can only be listed if it contains a “claim for the medicine itself” or a “claim for the use of the medicine”. This determination is generally easy, since many pharmaceutical patents have at least one listable claim to a new chemical compound or a new use of a known chemical compound (e.g., “use of drug X for treating disease Y”), or only claim non-listable processes of manufacture or intermediates having no therapeutic value as drugs.
In other cases, the determination is less clear. In an early case under the Regulations, it was decided that a claim to a pharmaceutical composition that includes a pharmaceutically active ingredient is a claim to the medicine itself. However, later cases have arguably restricted the scope of what would be considered such a claim. It has been held that a claim to a drug combined with an inhaler useful for delivering the drug was not a claim to the medicine itself, and a similar finding was made with respect to a drug contained within a transdermal patch. In more recent appellate decisions, claims reciting a controlled-release dosage form containing any one of a number of different active ingredients have also been found not to be claims to the medicine itself.
While these decisions suggest that patents protecting drugs in combination with pharmaceutical devices, patches or controlled-release dosage forms will not be accepted for listing, this is not necessarily the case. It may be possible during the prosecution of a patent application to add or amend the claims to improve the chances of having a resulting patent listed. A good strategy is to ensure that at least one claim specifically recites the active ingredient for which regulatory approval has been or will be obtained. Also, use claims reciting each utility for which approval has been or will be sought should be added.
It may also be possible to add claims reflecting other aspects of the invention that are more clearly related to the medicine itself or its use. For instance, in the case of controlled delivery, the inventive aspect might also be expressed as a use,
such as a use of the drug according to a particular dosing regimen. Even for those difficult cases in which the key part of the inventive combination is the device or dosage form, reference to the device in a claim may not be fatal. In one case, for example, the claims of one of the patents at issue referred to a “composition in a container”.
It is important to let the Canadian agent know early in prosecution that a patent application relates to a product for which regulatory approval from Health Canada has or will be obtained. Claims can be added or amended at any time during prosecution of a Canadian patent application, and if there are initially no claims giving rise to a listable patent, amendments can be made that may do so.