Thursday, June 13, 2013

Practice Notice on Dosage Regimes Difficult to Reconcile with Hughes J’s Finasteride Decision

The Practice Notice on Medical Uses released by CIPO on Monday is directed at “medical use claims, including dosage regimens and dosage ranges.” Unfortunately, it seems difficult to reconcile with the relatively recent decision of Hughes J in Merck v Pharmascience / finasteride (NOC), 2010 FC 510, 85 CPR(4th) 179 on exactly that point.

The notice begins by stating that “it is well established that methods of medical treatment and surgery are not statutory subject matter and are excluded from the definition of invention.” This is fair summary of the law. In my view the SCC decision in Tennessee Eastman v Commissioner of Patents, [1974] SCR 111, which is usually cited on this point, really turned on s 41, which is now repealed, but the Federal Courts have consistently read it more broadly, and the point is now established in the Federal Court jurisprudence, independently of the authority of Tennessee Eastman.

The Notice then states that “Medical use claims, however, are generally permitted as long as they do not equate to medical or surgical methods . . . The Federal Court has concluded, however, that inventions preventing physicians from exercising their skill and judgment in using a known compound for an established purpose effectively cover a method of medical treatment.” This is also a fair summary of the case law.

However, the Notice then goes on to say:

[If] it is determined after a purposive construction that a dosage regimen or dosage range is an essential element of a claim encompassing the use of a known compound in an established treatment, then the claim covers a method of medical treatment, and thus, is not compliant with section 2 of the Patent Act.

Where an essential element only serves to instruct a medical professional “how” to treat a patient, rather than “what” to use to treat the patient, this will lead to the conclusion that the claimed use encompasses a method of medical treatment.

The apparently blanket rejection of dosage regime claims is not consistent with the case law.

In Merck v Apotex / alendronate 2005 FC 755, 41 CPR(4th) 35, concerning 2,294,595, the inventive concept was the discovery that a single large weekly dose had fewer side effects than an equal amount taken on a daily basis [27], and the patentee claimed the composition in the specified dosage and dosing interval, as well the composition “for use” in the specified dosage and dosing interval [28]. Mosley J held that these claims were not an unpatentable method of medical treatment, though his reasoning was very cursory as he had held the patent invalid for obviousness [133]-[138]. In contrast, in Axcan v Pharmascience / URSODIOL 2006 FC 527, 50 CPR(4th) 321 concerning 1,318,590, Harrington J. in the Federal Court held that a claim to a dosage form of a pharmaceutical composition for treatment of cirrhosis was an unpatentable on the sole basis that it was a method of medical treatment. Harrington J described the holding of Mosley J in alendronate, but he did not attempt to distinguish it.

In finasteride Hughes J reviewed these cases and reconciled them by saying that "In Axcan, Harrington J. found the claim to be invalid because it was directed to a dosage range in which it was left to the physician to make on appropriate selection" [112]. At the same time Hughes J approved Mosley J's alendronate decision [112]. This is significant, because, as noted, subject matter was only a secondary consideration in Mosley J's decision, so it is relatively weak authority on its own. Consequently, Hughes J concluded that [114]:

a distinction must be made between claims that rely upon the skill and judgment of a medial practitioner and those that deal with a vendible product, be it a scalpel, X-ray machine or 1 mg tablet that are to be used or prescribed for use by such practitioner.

Thus in Hughes J’s view, it is not any dosage regime which is unpatentable, but only a dosage regime which requires skill and judgment.

This is reinforced by his holding on the facts that the claim in question was not unpatentable as being a method of medical treatment. In finasteride only Claim 5 of Patent 2,173,457 was at issue. After incorporation of prior references [5], Claim 5 reads:

5. The use of [finasteride] for the preparation of a medicament adapted for oral administration useful for the treatment of male pattern baldness in a person and wherein the dosage amount is about 1.0 mg.

Hughes J expressly construed this claim such that “having a dosage at about 1.0 mg” was an essential element [101]. Nonetheless, he held it was patentable subject matter: "In the present case, we have a 1.0 mg tablet taken as a daily dose. No skill or judgment is brought to bear. It is a vendible product and not a method of medical treatment" [114]. 

The Practice Notice cited Hughes J’s finasteride decision, but only in an introductory sentence saying that the Notice was intended to reflect judicial decisions. Despite that intent, I do not see how the statement that a claim is an unpatentable method of medical treatment if “a dosage regimen or dosage range is an essential element of a claim,” can be reconciled with finasteride. And apart from fine points of doctrine, there are now two cases holding dosage regime claims are patentable subject matter, and one to the contrary.


  1. The cases on dosage regimes are indeed hard to reconcile, almost as much with each other as with cipo's practice notice. I think there may be room to discern a logical distinction by looking at whether the exercise of a physician's judgement is required in order to achieve the non- obvious advantage associated with a particular dosage regime. This relates to the fact that dosage regime cases are a category of selection invention. If the application discloses a non-obvious advantage associated with a particular dosage regime, then the physician is not required to exercise any inventive skill to put the invention into practice. On the other hand, if this level of guidance is lacking from the application, then a physician's skill may be required to achieve any non-obvious advantage. There isn't room here to review all the decisions, but I think the cases would support this more nuanced distinction between patentable and unpatentable dosage regimes.

  2. I don't think you can say that there are two cases holding that dosage regime claims are patentable subject matter. Both Merck & Co., Inc. v. Pharmascience Inc. 2010 FC 510 and Merck & Co. Inc v. Apotex Inc. 2005 FC 755 were found patentable partly because the claims were for a vendible product.

    We have a 1.0 mg pill in the former case and a 70 mg pill in the latter case. The invention lies in the new amount of the drug. This can be distinguished from Axcan where the invention lies in a range of 13-15 mg/kg/day. In this case the judge reasons, " There is a distinction between the dosage in a capsule and a dosage range based on the patient's weight. As I read the claim, the emphasis is on the dosage range, and a dosage range is not a vendible product."

    I have yet to see a case where the invention lies in the dosage range (and not a specific dosage) and was found to be patentable under S2. It would be hard to argue that this type of claim did not cover an area for which a physician's skill or judgment is required.

  3. Anon 5:48, With respect to alendronate 2005 FC 755, the claims are to a certain pill dosage on a certain schedule, not just to the pill dosage itself. Claim 35 was to “Use of alendronate . . .as a unit dosage form comprising about 70 mg . . .according to a continuous schedule having a once-weekly dosing interval.” Claims 87 and 139 were to a dosage form “according to a continuous schedule having a once-weekly dosing interval.” It is true that in URSODIOL 2006 FC 527 Harrington J distinguished alendronate on the basis that in alendronate the claim was to a vendible product, but I don’t see that as a real distinction. I don’t see a once-weekly dosing interval as distinct from a dosage/kg/day regime. I don’t see that weighing the patient in order to determine the daily dosage requires any skill or judgment. Nor do I see any significance use of the claims in issue being to a range rather than a specific amount. There is no suggestion in the decision or the patent that it matters what dosage within that range is selected. The effect of the range is the same as the reference to “about” 70 mg in alendronate. While Mosley J in alendronate did say the claim was to a vendible product, that is just a label for a conclusion. He explicitly acknowledged that “All that has been discovered ... is that if the compound is administered once a week rather than daily, one of its disadvantageous side effects will be less than it otherwise would be.” It is true that Harrington J was of the view that a dosage regime is unpatentable as it seeks to monopolize something that is properly within the sphere of professional skill, but I don’t read him as saying that the invention was invalid because it required skill and judgment to practice. As I read it, he is saying that dosage regimes are per se within the sphere of professional skill and so are unpatentable, regardless of whether the particular dosage regime claimed itself requires the exercise of skill or judgment to implement it. In this, I think he is simply disagreeing with Mosley J.

    With respect to finasteride decision 2010 FC 510, it is true that the claim was to a pill “wherein the dosage amount is about 1.0 mg.” However, the inventive concept was that baldness can be treated with a low daily dose of finasteride [14]. Presumably the pill itself could be claimed because pills in that low dosage had not been made previously, when a higher daily dosage was thought to be necessary. It is true that claim validity should be assessed according to the invention as claimed, not the inventive concept, but I don’t see Hughes J’s reasoning as turning on the fact that it was possible in this case to claim the pill dosage rather than the dosage regime. I come back to his point at [114], quoted in the post, which, as I read it, says the claim is invalid if the claims themselves rely on the skill and judgment of a doctor. It is this point that I see as inconsistent with the practice notice. As I noted in the post, Hughes J explained Harrington J’s URSODIOL decision on the basis that the claims themselves in that turned on the skill of a doctor, and not, as I have just explained it, on the basis that dosage is per se within the judgment of a doctor, but that simply reinforces the point that for Hughes J the key distinction is whether the claims themselves leave something for the skill of the doctor, and not whether “an essential element instructs a professional ‘how’ to treat a patient.” As I understand Hughes J, he would hold the claims to be valid even if they instruct a professional “how” to treat a patient, so long as there is no skill or judgment required in implementing those directions - eg give 1 mg finasteride per day to treat baldness.

  4. An entertaining irony in all this is that the kind of claim that does the most to cover how and what a physician does is the kind of claim everybody agrees is allowable: "The use of X for treating Y." This leaves the dosing regime entirely in the physician's hands, and covers everything the physician might do.

  5. Indeed. For that reason I think that it is wrong to argue that methods of medical treatment are just not the kind of thinkg that should be patentable.

    I do think there is a real distinction to be made between such claims and claims which require the exercise of judgment in order to fall within the claim; in that case, it may be difficult to determine whether the doctor exercised her judgment in the manner specified the patent. I also understand the concern that doctors should not be prevented by providing the best treatment to their patient out of fear of a patent infringement action. But the best way of addressing that concern is to provide the physician with a defence, as in US 35 USC 287(c), rather than by holding methods of treatment invalid.