31 July 2006
Key Points:
In the recent decision of Merck v Arrow, the Full Federal Court held that claims directed to methods of preventing or treating osteoporosis by orally administering alendronate once weekly are not patentable inventions. This is because they do not claim a manner of new manufacture, but are merely the use of a known substance with known properties for a known purpose in a known manner. The Court also found the claims to be invalid as lacking novelty over the prior art, rejecting an argument that the prior art did not constitute an anticipatory reference because it called for more testing. The Court held that the testing called for was testing for regulatory approval, rather than testing leading to the invention, which is irrelevant to whether the prior art is anticipatory.
On 15 June 2006, the Full Federal Court of Australia handed down its decision in Merck & Co. Inc. v Arrow Pharmaceuticals Limited [2006] FCAFC 91 in relation to patent claims directed to methods of prevention or treatment of osteoporosis by the once weekly oral administration of a specific dosage of alendronate. The Full Court upheld the lower court decision in relation to all of the appealed claims, finding those claims both did not claim a manner of new manufacture and lacked novelty.
Background
In 2000, Merck filed a patent application that was granted as Australian Patent No. 741818. This was for an invention entitled "Method for inhibiting bone resorption" ("Method Patent"). The various claims of the patent were directed to methods of preventing or treating osteoporosis by the once weekly oral administration of a specified dosage of either alendronate, (or one of its pharmaceutically acceptable salts or esters) ("Alendronate") or risedronate (or one of its pharmaceutically acceptable salts or esters) ("Risedronate"). The patent also included composition claims directed to once weekly oral pharmaceutical compositions containing either Alendronate or Risedronate. By the time that the application for the Method Patent was filed in 2000, the oral administration of pharmaceutical compositions containing Alendronate as a method of treatment for osteoporosis had a long history.
The Method Patent was the third in a series of Merck owned patents relating to compositions and methods of treating or preventing osteoporosis using alendronate. In about 1983, patents were granted in various countries although notably not in Australia. These patents contained claims relating generally to alendronic acid, compositions containing the same and methods of inhibiting bone resorption by administering an effective amount of alendronic acid to a patient in need thereof ("Base Patent"). In about 1987 or 1988, Merck acquired the rights to the Base Patent throughout the world and set about using them to best effect.
In 1990, Merck filed a patent application that was granted as Australian Patent No. 625704, which is currently in force and is due to expire on 8 June 2010. That Australian Patent includes claims directed to the specific alendronate monosodium trihydrate species, compositions containing the same, a process for preparing alendronic acid or salts and methods for treating or preventing osteoporosis by administering the same.
By October 1995 alendronate was approved for sale and was sold by Merck in the United States under the trade name "Fosamax". This was prescribed in the form of a daily dosage for the treatment of osteoporosis. Fosamax was initially registered in Australia pursuant to the Therapeutic Goods Act 1989 (Cth) in July 1996 on the basis of the same daily dosage. On 1 October 1996, Fosamax was approved in Australia for the treatment of osteoporosis at that daily dosage.
In addition to these prior Merck patents, the specification of the Method Patent also incorporated (by reference) two "prior art" documents. These included a 1993 patent to Strein and a 1995 patent to Goodship. The Strein patent teaches weekly administration of effective amounts of alendronate for the treatment of osteoporosis, an advantage being reduced GI side effects. By analogy with the treatment of osteoporosis, the Goodship patent teaches weekly administration of alendronate (in therapeutically effective amounts) for treatment of prosthesis loosening and prosthesis migration. The range of dosages includes those identified in the Method Patent claims.
Arrow sought revocation of the claims of the Method Patent. Merck did not defend the claims as granted. Instead Merck secured amendments, with the result that the Method Patent as addressed by the lower court contained only 10 claims - 4 method claims and 6 composition claims. Arrow sought revocation of all seven of the amended claims directed to a method or composition in which the active ingredient was Alendronate. It did not seek revocation of the other three claims directed to a method or composition in which the active ingredient was Risedronate.
All seven of the Alendronate-based claims were held invalid by the primary judge. Merck only pressed its notice of appeal in relation to the three Alendronate based method claims. It did not challenge the finding of invalidity in relation to the four Alendronate based composition claims.
Manner of new manufacture
Unlike the position in many jurisdictions, methods of medical treatment in general have long been considered to constitute a manner of manufacture, and to be patentable subject matter, in Australia. However, each claimed method must still be assessed individually to ensure that it satisfies the requirements for patentability, including whether it is itself a manner of new manufacture.
It is well established that:
At first instance, having regard to the disclosures in the specification only, Justice Gyles held that:
"each of the so-called method claims was one way of utilising alendronate and its known qualities for the known purpose of preventing or treating osteoporosis by a known method of oral administration. They are in the nature of directions for use. That does not constitute an invention or a manner of manufacture."
The Full Court described the appealed claims as directed to:
"a method of treatment (or prevention) of a particular disease with an amount…of a known chemical or drug (alendronate) already known to treat that disease, with the sole asserted novelty being that the amount of the drug…or the drug per se…is taken weekly."
The Full Court then upheld the first instance decision, stating:
"The Patent specification discloses no new substance, no new characteristic of a known substance, no new use and no new method. There is, therefore, no manner of new manufacture."
Novelty
The Full Court also upheld the lower court's decision as to novelty, finding the claims invalid as anticipated by the prior art.
Merck argued that the prior art merely disclosed a need for further testing, rather than a complete discovery of the claimed invention. On that basis, Merck argued, it was not an anticipatory reference sufficient to render the claims invalid.
Like the lower court, the Full Court rejected this argument. The Full Court held (particularly in relation to pharmaceutical patents), that where it is a matter of notoriety that prolonged testing for the purpose of regulatory approval must occur between the stage of patent application and commercial marketing:
"It will always be necessary to distinguish between experiments leading to an invention and subsequent experiments for checking and testing the product or process the subject of the invention. The latter would not be material to obviousness."
The Full Court further held that the testing referred to in the prior art was in the nature of the former type of testing and concluded:
"the claims in question are for a very simple method: oral administration of a known (indeed commercially marketed) drug at a specified dosage over a specified period. Working the invention does not require any special skill. Details of this method are clearly conveyed in the [prior art].. . Nothing additional is required."
An application for special leave to appeal has been lodged in the High Court and will be heard soon.
For further information, please contact John Collins.
