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Dosage Regimens in Canada: Patentable Subject Matter?

April 10, 2012

It is well known that methods of medical treatment do not constitute patentable subject matter in Canada. One of the reasons for this prohibition is to prevent a medical professional from being barred from practicing a beneficial medical treatment that may be based on their skill and judgment. Accordingly, claims directed to surgical, medical, dental, or physiotherapeutic methods of treatment are not patentable. In addition, there have been several recent court decisions in Canada where dosage regimens were held to be methods of medical treatment, and therefore not patentable subject matter, and the corresponding patents held to be invalid and unenforceable.

During prosecution of a patent application, objections to method of medical treatment claims are generally overcome by simply rewriting the claims in a manner that is acceptable to the Canadian Patent Office. For example, a claim to a method of treating disease X with compound Y would not constitute patentable subject matter, yet by simply rewriting the claim as a use of compound Y to treat disease X the subject matter-based objection will generally be overcome.

However, corresponding objections to claims where the point of invention is how a medicine is to be used, such as a dosage regimen, have now become more difficult to overcome and patents containing such claims are being invalided by the courts.

For example, in two recent court decisions, Axcan Pharma Inc. v. Pharmascience Inc. 2006 FC 527, and Janssen Inc. v. Mylan Pharmaceuticals ULC. 2010, FC 1123), it was held that the claims at issue contained a dosage range that required a physician’s skill and judgment to select the appropriate value based on information from the patient. In Axcan, this information was the patient’s weight and in Janssen, it was the patient’s response to treatment. Also, in a recent Patent Appeal Board decision (Commissioner’s Decision no. 1292, 2009), the Board ruled that a claim reciting 50 to 300 units of botulinum toxin for treating pain was a method of medical treatment.

It should be noted, however, that there have also been recent cases where more specific dosage regimens have been held to be patentable in Canada. In Merck & Co. v. Pharmascience 2010 FC 510, a claim to a 1.0 mg tablet taken as a daily dose was held to be patentable subject matter on the basis that it is a “vendible product” and no skill or judgment of a physician is required. Similarly, in Merck & Co. Inc. v. Apotex, 2005 FC 755, a claim directed to 70 mg of a particular drug on a once-weekly dosing interval was also held to be patentable subject matter. Based on these court decisions, a fixed amount of a drug administered on a fixed schedule is not considered a method of medical treatment and, therefore should constitute patentable subject matter.

In view of the above-cited cases, it appears that the state of protection available in Canada for dosage regimens is somewhat unclear. For example, it appears that a claim directed to a unit dosage form is patentable subject matter. Therefore, individual claims in the same patent directed to 1.5 mg, 2.0 mg, 2.5 mg, or 3.0 mg tablets taken on a daily basis should constitute patentable subject matter. However, collectively, such claims would provide similar protection to a single claim directed to a dosage range between 1.5 and 3.0 mg taken on a daily basis, which, considering the current state of law, would not be patentable subject matter.

Accordingly, for companies developing novel and inventive dosage regimens, or other means for administering a medicine to a patient, it would be prudent to consider alternative ways to claim the invention. For example, including a list of specific single dosages to support a separate claim to each of these amounts (note that there are no excess claim fees in Canada, therefore including hundreds or thousands of claims in a single application is not, at least, financially prohibitive), or including kit and/or pharmaceutical package type claims, are some of the strategies that can be attempted. Regardless, speaking with a patent agent specializing in this area prior to submitting a patent application where the invention relates to how a medicine is administered is highly recommended.

Michael Fenwick, B.Sc., M.Sc. (Org. Chem.), LL.B., is an associate lawyer with Bereskin & Parr LLP's Biotechnology & Pharmaceutical practice group. Michael can be reached in Toronto at 416.957.1665 or mfenwick@bereskinparr.com.

Patricia Folkins, B.Sc., Ph.D. (Chem.), is a partner with Bereskin & Parr LLP and is the leader of the Chemical practice group. She can be reached in Mississauga at 905.817.6101 or pfolkins@bereskinparr.com.

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Author(s):

Michael Fenwick Michael Fenwick
B.Sc., M.Sc. (Org. Chem.), LL.B.
Partner
416.957.1665  email Michael Fenwick
Patricia Folkins Patricia Folkins
B.Sc. (Honours Chem.), Ph.D. (Org. Chem.)
Partner
905.817.6101  email Patricia Folkins