Ranbaxy Laboratories Ltd v Warner Lambert Company

• Jurisdiction: Ireland
• Judge: Mr. Justice Clarke
• Judgment Date: 10 July 2007
• Neutral Citation: [2007] IEHC 256
• Court: High Court
• Docket Number: [2004 No. 18683
• Date: 10 July 2007

[2007] IEHC 256

THE HIGH COURT

[No. 18683 P/2004]

Ranbaxy Laboratories Ltd & Ors v Warner-Lamber Company

BETWEEN

RANBAXY LABORATORIES LIMITED, RANBAXY EUROPE LIMITED AND RANBAXY IRELAND LIMITED

PLAINTIFFS

AND

WARNER-LAMBERT COMPANY

DEFENDANT

PATENTS ACT 1992 S54

KIRIN-AMGEN v HOECHST MARION ROUSSEL 2005 RPC 9

PATENTS ACT 1992 S45(1)

PATENTS ACT 1992 S45(3)

CONVENTION ON THE GRANT OF EUROPEAN PATENTS 1973 ART 69

CATNIC COMPONENTS LTD v HILL & SMITH LTD 1982 RPC 183

GENERAL TYRE & RUBBER CO LTD v FIRESTONE TYRE & RUBBER CO LTD 1972 RPC 457

LUBRIZOL CORP v ESSO PETROLEUM CO LTD 1998 RPC 727

TICKNER v HONDA MOTOR CO LTD UNREP 2002 EWHC 8 (PATS)

SOCIETE TECHNIQUE DE PULVERISATION (STEP) v EMSON EUROPE LTD 1993 RPC 513

IMPROVER CORP & ORS v REMINGTON CONSUMER PRODUCTS LTD 1990 FSR 181

TELSONIS AG'S PATENT 2004 RPC 38

RANBAXY (UK) LTD & ARROW GENERICS LTD v WARNER-LAMBERT CO UNREP 2005 EWHC 2142

PATENTS ACT 1977 (UK)

INTELLECTUAL PROPERTY

Patent

Principles of construction - Construction of chemical formula in patent - Skilled addressee - Common general knowledge as of priority date - Rational patentee test - Extent of protection afforded by patent - Application for declaration that patent would not be infringed - Whether limitation in patent to effect that claim limited to racemate of chemical compound - Whether plaintiffs' product would infringe defendant's patent - Kirin-Amgen Inc v Hoechst Marion Roussel Ltd [2005] 1 All ER 667 considered; Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183, General Tire & Rubber Co v Firestone Tyre & Rubber Co [1972] RPC 457, Lubrizol Corp v Esso Petroleum Co Ltd [1998] RPC 727 and Ranbaxy UK Ltd v Warner-Lambert Co [2006] All ER (D) 322 followed - Patents Act 1992 (No 1), ss 45 and 54 - Convention on the Grant of European Patents 1973, article 69 - Claim dismissed (2004/18683P - Clarke J - 10/7/2007) [2007] IEHC 256

Ranbaxy Laboratories Ltd v Warner-Lambert Co

The defendant development a synthetic compound which was patented in Ireland. The plaintiffs sought a declaration under s. 54 of the Patent Act 1992 that the manufacture and/ or import and/ or sale of a compound in Ireland would not infringe the defendant's Irish patent.

Held by Clarke J. that the plaintiffs' potentially competing product infringed the patent.

Reporter: R.W.

1. Introduction

2 2 1.1 The search for drugs effective against cholesterol has intensified in recent years. In the middle 1980's a number of break throughs occurred. By May, 1986, a class of compounds known as "statins" was recognised as being of potential application for cholesterol lowering medicines. In particular natural products such as mevinolin and compactin were recognised as potentially key. In that context the defendant ("Warner-Lambert") developed a synthetic compound which was patented in very many jurisdictions including Ireland. The plaintiffs ("Ranbaxy") now seeks a declaration, under s. 54 of the Patent Act 1992 ("the Act"), that the manufacture and/or import and/or sale of a compound called atorvastatin calcium in Ireland would not infringe Warner-Lambert's Irish patent. While there are other proceedings between the parties concerning the validity of that patent, no such challenge is brought in these proceedings. Therefore the net question that arises concerns whether Ranbaxy's "atorvastatin calcium" infringes Warner-Lambert's Irish Patent No. 60014.

3 3 1.2 That patent was granted for an invention entitled " Trans- [2-( 3-or 4-carboxamido-substituted pyrrol-1-yl) alkyl]-4- hydroxpyran-2-one inhibitors of cholesterol synthesis". In order to understand the dispute between the parties it will be necessary to turn, in early course, to the underlying chemistry behind both the patent and Ranbaxy's competing product. However, as will become clear, the key issue in the dispute concerns the proper interpretation of Warner-Lambert's Irish patent. Ranbaxy argues that, properly construed, that patent relates only to what are described as "racemic mixtures" and that its competing product is not a racemic mixture. Warner-Lambert argues that a proper construction of its Irish patent covers a wider range of molecules. The true net issue between the parties is, therefore, as to the proper construction of Warner-Lambert's Irish patent. If it is to be construed in the way contended for by Warner-Lambert then it follows that it is wide enough to cover Ranbaxy's competing product. If, on the other hand, it is, properly construed, to be given the narrower interpretation contended for on the behalf of Ranbaxy then it is equally clear that the competing product produced by Ranbaxy is not covered. The real issue, therefore, concerns the construction of the Irish patent.

4 4 1.3 Finally, before turning to the underlying chemistry necessary to understand and, therefore, construe the patent it should be noted that the same or similar disputes exist between the parties to these proceedings, or other appropriate corporate entities associated with them, in a whole range of other jurisdictions. A number of those disputes have been the subject of judicial determination and it will be necessary to refer to the relevant litigation in due course. However it is first appropriate to turn to the underlying chemistry.

2. Stereochemistry

2 2 2.1 Stereo chemistry is the study of the three dimensional structure of molecules. Many will recollect from their school days the basic underlying structure of molecules being comprised of a number of atoms. Basic chemical formulae represent a molecule by describing the types and number of atoms involved. At a slightly more complex level isomers are compounds that have the same number and type of atoms but where the atoms are arranged in a different manner.

3 3 2.2 One particular type of isomer is termed a stereoisomer. The differences between stereoisomers exist in three dimensions. This leads to a consideration of how the three dimensional structure of certain molecules are, by convention, depicted in written form.

4 4 2.3 Again chemical formulae can be written as a continuous series of letters depicting particular atoms and appropriate numbers representing the number of atoms in the molecule concerned. Alternatively the composition of a molecule can be shown in a pictorial fashion setting out, in a two dimensional way on the page, the way in which the relevant atoms are arranged. By convention a dash is used to represent bonds between atoms in the plane of the page, a wedge is applied for bonds coming upwards out of the plane of the page and a broken or hashed line is used for bonds that go behind or down from the page.

5 5 2.4 These conventions are important to the issues which arise in this case because the patent (as will indeed be the case with any chemical patent) is represented in written form. It is the proper interpretation of that written form which, therefore, lies at the heart of the dispute between the parties in this case.

6 6 2.5 The carbon atom (along with hydrogen and oxygen) forms the basis of organic chemistry. A carbon atom is capable of bonding with four other atoms or groups of atoms in a way which, in three dimensional terms, resembles a tetrahedron. The representation below shows two different three dimensional representations of such a tetrahedron. In each case the centre is a Carbon atom. It will also be noted that in each case four different other atoms or groups of atoms numbered respectively a, b, c, d, are attached. From the notation referred to above, the "c" atoms (being represented by a wedge) should be visualised as being above the page while the "d" atoms (being represented by a hashed line) should be seen as being below the page. The a and b atoms (being attached by a dash) should be seen as being in the plane of the page. In any of the relevant cases what is attached to the carbon atom may also be a group of atoms rather than a single atom. It will also be seen that the two molecules (1 and 2) represented are mirror images of each other and are not capable of being superimposed one on the other. Any physical object (such as the two hands of a human being) whose mirror image is not identical with itself is said to be chiral. Where stereoisomers exist that are not superimposable mirror images of each other they are known as enantiomers. Therefore enantiomers will be made up of the same atoms arranged in almost the same way save that they are mirror images of each other in the way depicted.

Mirror plane

2 2 2.6 It has been well known for some time that despite their chemical similarity enantiomers often have very distinct properties. The tragic case of thalidomide is often put forward as one of the best known examples. One enantiomer in that case was an effective sedative. Unfortunately the other enantiomer caused serious birth defects. Regrettably the adverse effects of the latter enantiomer were not discovered until after many tragic cases had occurred.

3 3 2.7 There would appear to be a number of different conventions used for the purposes of distinguishing between different enantiomers of the same compound. One such convention relies upon the fact that enantiomers typically rotate plane polarised light in either a clockwise or anticlockwise direction depending on which enantiomer is involved. Using this notation the enantiomer which rotates plane polarised light in a clockwise direction is labelled "+" or "d" (the latter being for dextrorotatory). The enantiomer which rotates polarised light in an anti-clockwise fashion is labelled "-" or "l" for levorotary. This leads to the definition at the heart of the chemistry involved in the compounds with which I am concerned. A racemic mixture (or racemate) is a mixture of two enantiomers which is, for all practical intents and purposes, equal. It is...