The global Lipitor patent battle
Copyright Monday, July 10, 2006 Duncan Bucknell Company
Despite litigation in at least ten jurisdictions across the world, Ranbaxy has so far been unable to obtain launch before patent expiry (~2011). (Further analysis below.)
On 28 June 2006, the United Kingdom Court of Appeal handed down its decision in Ranbaxy (UK) Ltd. v Warner-Lambert Company Rev 1 [2006] EWCA Civ 876.
In essence, the UK Court of Appeal held that the basic patent was infringed by the R, R enantiomer, but the enantiomer patent was not novel and invalid. Thus, (barring a successful appeal to the House of Lords), Ranbaxy will be unable to launch generic Atorvastatin (Lipitor) in the United Kingdom until 2011.
Comment
Two key patent families have been in issue in the various proceedings around the world (other, process patents have also been litigated in some countries). The first key family derives priority from US19860868867 andclaims a racemic mixture of enantiomers of Atorvastatin (‘the basic patent’). The second key family derives priority from US19890384187 and claims the calcium salt of the R, R enantiomer of Atorvastatin (‘the enantiomer patent’).
The pattern of litigation does not suggest a coordinated, strategic attack by Ranbaxy. Given the overwhelming lack of success to date, it is difficult to see what Ranbaxy hopes to achieve in continuing the litigation.
A trite answer (which may be all that is needed), is that given the size of the market for Lipitor, success in even one moderately-sized jurisdiction will more than pay for all of the litigation.
Clearly, Lipitor illustrates this important principle, which should be factored into global litigation strategy along with other key factors such as cost and time to first judgment (see my article ‘Value for money in global patent litigation: Relative cost and time to first judgment in eight key countries’).
What happened in the UK?
In relation to the basic patent, the UK Court of Appeal held that the R, R enantiomer infringed claims which depicted the racemic mixture. This finding was based substantially on the common general knowledge of the skilled addressee of the patent, which included knowledge that the molecule would have two chiral centres, that other molecules in the class (Statins) had at least one chiral centre and that the R, R enantiomers would be more active and readily separable.
The UK Court of Appeal held that the enantiomer patent was not novel in light of earlier filed WO 89/07598. This was essentially because the R, R enantiomer had been prior disclosed in the following terms "The preferred isomer in this invention is the 4R,6R-isomer of the compounds of Formulas I, Ia and XII above" and the patent clearly taught that (amongst others), the Calcium salt could be made. To quote Pumfrey J from the first instance decision:
"It is no answer to an allegation of anticipation that the specification gives clear and unmistakable directions to use the common general knowledge to produce a specific material."
The Court of Appeal saw no need to also determine obviousness of the enantiomer patent which it held invalid. (As the Court of Appeal mentioned, it is extremely unlikely that leave to appeal to the House of Lords would be granted, and that this Appeal would be overturned. (See — Synthon BV v SmithKline Beecham Plc [2005] UKHL 59.) If that happened, then the case would be remitted to the Court of Appeal to determine obviousness as well.)
Background
The UK appeal was from the judgment of Punfrey J in Ranbaxy (UK) Ltd. v Warner-Lambert Company Rev [2005] EWHC 2142 (Pat), [2006] FSR 14.
In that case, Pumfrey J refused Ranbaxy’s application for a declaration of non-infringement of Warner-Lambert's EP (UK) 0 247 633 (basic patent) but held Warner-Lambert's EP (UK) 0 409 281 (enantiomer patent) invalid for lack of novelty and obviousness.
