ACLASTA dosing regimen claims directed to unpatentable subject matter


zoledronic acid

On September 25, 1993 Mr. Justice Hughes of the Federal Court of Canada released his Reasons for Judgment in prohibition application between Novartis and Cobalt involving the drug ACALASTA® (zoledronic acid for injection) and Canadian Patent No. 2,410,201.

The 201 Patent is generally directed to the pharmaceutical use of bisphosphonates for the treatment of osteoporosis. More specifically, the 210 Patent is directed to the use of zoledronic acid in a once-a-year dosing regimen. Representative Claim 16, when expanded for claim dependency provides:

Use of zoledronic acid, a pharmaceutically acceptable salt thereof, or a hydrate thereof for the treatment of postmenopausal osteoporosis wherein the zolderonic acid, salt or hydrate is in a unit dosage form of about 5 mg which is administered intermittently, with a period of about one year between the first and each subsequent administration, wherein each administration is intravenous.


Justice Hughes noted  that obviousness is one of the most difficult issues faced by a Court in patent litigation. Based on evidence of one of the named inventors that most people thought he was “crazy” for testing zoledronic acid administration at one year, Justice Hughes concluded that the inventor “dared to go beyond what a person of ordinary skill in the art would have done at the time” and accordingly found Cobalt’s allegation of obviousness unjustified.

Method of Medical Treatment

After a comprehensive review of Supreme Court of Canada jurisprudence dealing with method of medical treatment, including Tennessee Eastman, Shell Oil, and AZT,  and the decisions of Justice Mosley in Merck & Co. v. Apotex Inc., Justice Harrington in Axcan Pharma Inc. v. Pharmascience, the Patent Appeal Board in Re Allergan, Inc. Patent Application No 2,300,723, his own decision in Merck & Co Inc v. Pharmascience and the decision of the Justice Barnes in Janssen Inc. v. Mylan Pharmaceuticals ULC, Justice Hughes concluded:

[91] What the jurisprudence establishes is that a claim to a vendible product, including a substance intended for the treatment of a medical condition, can be good subject matter for a patent claim. Thus, claims such as the following are proper subject matter:

  •  The substance X for the treatment of Y
  • The substance X in the form of a 5 mg tablet for the treatment of Y

[92] What is improper subject matter is a claim that encompasses the skill of medical professional, such as:

  • The closure of a surgical incision by the use of adhesive X
  • The use of substance X in a dosage range between A and B for the treatment of X

Relying on disclosure in the 210 patent that the mode of administration and dosage may be selected by the attending physician taking into account particulars of the patient, and expert evidence from Cobalt that the mode and dosage will be determined by the physician based on his or her professional skill and professional judgment, Justice Hughes held that all claims were directed to non-patentable subject matter:

[99]… However, because each claim of the ‘201 patent, directly or by incorporation by reference, includes as well treatment by intermittent dosages with some claims specifying a dosage range and other specifying specific dosages; and some claims claiming more frequent intervals of dosing, and others less; that the claims include that which lies within the skill of the medical practitioner and are thus invalid.

Justice Hughes also concluded that the Court should disregard the artificial nature of “Swiss–style” claims (i.e. “use of a X in the manufacture of a medicament for the treatment of Y”) to look to the real subject matter of the claims. Where, as here, the real invention lies in the dosing regimen, it is unpatentable subject matter regardless of the wordsmithing used by the patent agent in the claim.

A copy of Justice Hughes’ Reasons for Judgment may be found here.

Novartis has appealed Justice Hughes’ Judgment (Court File No. A-318-13)