Examples of purposive construction analysis of medical use claims for statutory subject-matter evaluation

Note that the claims below are only examples for training purposes. Each application must be considered on its own merits and purposive construction must be used to evaluate statutory subject-matter. Further, statutory does not equate to patentable.

1. New compound

  1. Compound X.
  2. Use of compound X to treat Y.
Background of the invention/Common general knowledge Disorder Y could be treated with drugs A, B or C. Compound X had never been created.
Problem to be solved Need for a new treatment for disorder Y.
Practical solution Compound X (and its use).
Essential elements Compound X (and its use).
Construed claims
  1. Compound X, useful for treating Y.
  2. Use of X to treat Y.
Is it statutory? Yes, claim 1 is a composition of matter and claim 2 is an art. They are both directed to the "what".

Note: adding dosage ranges or regimen to claim 2 or any dependent claim would not make it non-statutory. The solution is in the new compound. Additional features are unnecessary limitations to the scope of the monopoly, but do not render the claim non-statutory.

2. New use of a known compound

  1. Use of compound X to treat Y.
Background of the invention/Common general knowledge Compound X exists already and is known to treat Z. Disorder Z is unrelated to disorder Y.
Problem to be solved Need for a new treatment for disorder Y.
Practical solution Use of X.
Essential elements Use of X.
Construed claim Use of X to treat Y.
Is it statutory? Yes, the claim is directed to the "what".

Note: adding dosage ranges or regimen to claim 1 or any dependent claim would not make it non-statutory. The solution is in the new use. Additional features are unnecessary limitations to the scope of the monopoly, but they do not render the claim non-statutory.

3. New fixed dosage form of a known drug for a known use

  1. Use of a 100 mg dosage unit of X to treat Y.

Context: the usual treatment of Y using drug X was in the range of 20-50 mg, because above 50 mg the secondary effects became more important. The inventors discovered that with a much higher dose i.e. 100 mg, the treatment effect of the drug was multiplied by a factor of 5 and outweighed the increased secondary effect. Using the new high dose formulation, patients could be cured in a much shorter time (days instead of weeks). 

Similar to Merck & Co., Inc. v. Pharmascience Inc., 2010 FC 510.

Background of the invention/Common general knowledge Compound X already exists and is known to treat Y. The usual doses are within the range of 20-50 mg.
Problem to be solved Need for an improved treatment formulation of X to treat Y.
Practical solution A 100 mg dosage unit of X.
Essential elements A 100 mg dosage unit of X.
Construed claim Use of a 100 mg dose unit of X to treat Y.
Is it statutory? Yes, the claim is directed to the "what". The essential elements of the claim are directed to a specific product, a dosage unit.

4. New dosage range of a known drug for a known use

  1. Use of compound X to treat Y in a range of 13 to 15 mg/kg/day.

Similar to Axcan Pharma Inc. v. Pharmascience Inc., 2006 FC 527; and also CD 1292.

Background of the invention/Common general knowledge Compound X already exists and is known to treat Y.
Problem to be solved Need for an improved treatment of Y using X.
Practical solution A dosage for X where the dose is calculated to be between  13 to 15 mg/kg/day.
Essential elements 13 to 15 mg/kg/day of X.
Construed claim Use of a dosage range of 13 to 15 mg/kg/day of X to treat Y.
Is it statutory? No. The claim is directed to the "how" and since the dosage range is an essential element of the claim and requires the skill and judgment of a physician to make a determination as to the dose the patient receives, the claim is not statutory. The claim is not directed to the use of a specific fixed dose or formulation. This amounts to a method of medical treatment and is not compliant with Section 2 of the Patent Act.

Note: The level of effort required by the physician is not considered. Even if the dosage claimed was a specific value e.g. 14 mg/kg/day, the physician still has to determine for each patient what the specific dose to administer is. Despite this being a very simple calculation, it requires the physician to use its skills.

5. New dosage regimen of a known drug for a known use

Example 5.1

  1. Use of drug X to treat Y in a first dosage of 8 mg/day, a second dosage of 16 mg/day and a final dosage of 24 mg/day, wherein said first dosage is for 4 weeks, said second dosage is for 4 weeks; and said final dosage is for use thereafter, wherein said use of the first dosage for 4 weeks results in a lower final dosage.
Background of the invention/Common general knowledge Compound X already exists and is known to treat Y. Usual treatments used a continuous dosage of 16 mg/day (16 mg dosage units).
Problem to be solved Need for an improved treatment of Y using X.
Practical solution A dosage regimen divided in 3 phases with respective doses of 8, 16 and 24 mg/day, the first 2 phases lasting 4 weeks each, the remainder of the treatment being at 24 mg/day, which is appropriate for all patients and does not require adjustments.
Essential elements Use of compound X for 4 weeks at 8 mg/day, then for 4 more weeks at 16 mg/day, and afterwards at 24 mg/day.
Construed claim Use of, first, 8 mg/day of X for 4 weeks, followed by 16 mg/day of X for 4 weeks, and finally 24 mg/day of X for the remainder of the treatment, to treat Y.
Is it statutory? Yes, the claim defines specific doses for a specific administration schedule; the treatment does not require the judgement of a professional (no range of dose or of duration).

Note: the claim would not be statutory if, after purposively construing the claim, it is determined that the schedule claimed is a titration. A patient’s titration always requires monitoring by a professional, who will adjust the treatment accordingly.

Example 5.2

  1. Drug X for use in an orally administrable unit dosage form comprising 70 mg of X to treat Y in a human on a continuous schedule having a once-weekly dosing interval.

Similar to Merck & Co. Inc. v. Apotex Inc., 2005 FC 755.

Background of the invention/Common general knowledge Compound X already exists and is known to treat Y. Usual treatment used a daily dosage of 8 mg.
Problem to be solved Need for an improved treatment formulation of X to treat Y.
Practical solution A weekly instead of daily formulation of X. The weekly formulation is 70 mg.
Essential elements 70 mg dosage form of X.
Construed claim Use of a dosage formulation of 70 mg of X, for weekly administration, to treat Y.
Is it statutory? Yes, the invention lies in the higher dose formulation, a specific product. The claim defines the interval and the duration, but by themselves they do not make the claim non-statutory. The analysis is done looking at the essential element of the claim, which is the new formulation (which itself leads to a different type of treatment).

Example 5.3

  1. Use of a 10 mg dosage unit of drug X to treat Y in a human for intermittent administration with a period of about one month between the first and each subsequent administration.

The description indicates that “about one month” means 3 to 5 weeks, depending on the patient. A physician is required to monitor the patient to determine the precise dosing schedule.

Background of the invention/Common general knowledge Compound X already exists and is known to treat Y. Usual treatment is a biweekly unit dosage of 10 mg.
Problem to be solved Need for an improved treatment schedule of the 10 mg unit dosage of X to treat Y.
Practical solution A monthly instead of biweekly administration of the 10 mg unit dosage, where monthly means every 3 to 5 weeks.
Essential elements A 3-5 week administration schedule of 10 mg of X.
Construed claim Use of a 10 mg dosage unit of X to treat Y on a 3-5 week administration schedule.
Is it statutory? No. The essential elements include a dosing schedule incorporating a range which requires the skill and judgement of a physician. The examiner must construe the claim to clarify the meaning of the expression “about monthly” and the description indicates that it means from 3 to 5 weeks, as determined by a physician. The claim is thus construed to be a method of medical treatment and not compliant with S.2.

6. New physical formulation of a known drug for a known use (new area of administration)

Example 6.1

  1. Use of an orally administrable pharmaceutical composition of X to treat Y characterized by 90% by weight of X being formulated in granules in a size range of 0.1-0.5 mm.

Context: drug X was used to treat Y, but could not be administered orally because it was degraded by the acid in the stomach. The drug had to be dissolved and administered intravenously, which required medical assistance or an administration device permanently inserted in the patient. The inventors discovered that by controlling the manufacturing process of drug X so that the particle size is mostly in the range of 0.1-0.5 mm, bioavailability of the drug taken orally becomes acceptable. The particles are large enough that only a small portion of the surface of the granules is actually degraded by the stomach environment, and the remaining particles, once in the gut, are small enough to be efficiently absorbed by the body to transfer the drug to the bloodstream.

Background of the invention/Common general knowledge Compound X already exists and is known to treat Y. Compound X is known to be degraded by acid conditions. Drug formulation techniques to control the size distribution of particles are well known.
Problem to be solved Need for an oral formulation of X to treat Y.
Practical solution Control the particle size of X to have 90% by weight of X being formulated in granules in a size range of 0.1-0.5 mm.
Essential elements Orally administrable pharmaceutical composition of X characterized by 90% by weight of X being formulated in granules in a size range of 0.1-0.5 mm.
Construed claim Use of an orally administrable pharmaceutical composition of X, to treat Y, characterized by 90% by weight of X being formulated in granules in a size range of 0.1-0.5 mm.
Is it statutory? Yes, the claim is directed to a "what": the new formulation.

Example 6.2

  1. Use of a transdermic pharmaceutical patch of X on an upper leg to treat Y.

Context: the inventor discovered that using patches of X on the upper leg instead of the upper arm resulted in an increased availability of drug X in the body because of the higher blood circulation in the leg compared to the arm resulting from the movements and activities of the patients throughout the day.

Background of the invention/Common general knowledge Transdermic patches of compound X already exist to treat Y. They are usually applied to the upper arm.
Problem to be solved Need for an improved administration method of X to treat Y.
Practical solution Use the patch of X on the upper leg instead of on the arm.
Essential elements Use of the patch of X on the upper leg.
Construed claim Using a transdermic pharmaceutical patch of X on an upper leg, to treat Y.
Is it statutory? Yes, it is statutory. The invention does not require the skill and judgment of a physician; it is appropriate for all patients and does not require adjustment.

7. Known compound, for a specific group of patients

Example 7.1 patient sub-population

  1. Use of X to treat Y in a patient population having the gene mutation ABC.

Context: X was already used to treat Y. The inventors discovered that patients having the gene mutation ABC in their DNA responded more efficiently to the treatment (lower dose or shorter treatment).

Background of the invention/Common general knowledge Use of X to treat Y was already known. The mutation ABC and its effect was unknown.
Problem to be solved Need for an improved efficiency of X to treat Y.
Practical solution Limiting the treatment of Y to a sub-population of patients having mutation ABC.
Essential elements Treating patients having the gene mutation ABC with X to treat Y.
Construed claim Use of X to treat Y only on patients having the gene mutation ABC.
Is it statutory? Yes, it is statutory. The new limitation does not require the judgement of a professional, the population is defined.

Note: In such cases, the claim will be anticipated, because in the population already treated, some already presented the ABC gene mutation, and thus treating them with X for Y is not novel. This alleged invention does not qualify as a "selection" because, in a selection, all of the range claimed must be novel. The claim did not define a specific treatment that can be distinguished from the prior art treatment.

Example 7.2 distinct patient population

  1. Use of X to treat urinary incontinence during pregnancy.

Context: drug X was used to treat urinary incontinence in male patients suffering from prostate cancer. The inventors discovered that the compound could be administered to women, to treat urinary incontinence during pregnancy.

Background of the invention/Common general knowledge Use of X to treat urinary incontinence in men suffering from prostate cancer is known.
Problem to be solved Need for treatment of urinary incontinence during pregnancy.
Practical solution Use of X.
Essential elements Use of X.
Construed claim Use of X to treat urinary incontinence during pregnancy.
Is it statutory? Yes, the invention is a new use of a known compound. Drug X was not known to treat urinary incontinence in women (it was never used or tested). This qualifies as a new use, because the patient group is distinct from those being treated by X.
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