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Friday, 15 July 2011

Not Nexium OK for Import - Ranbaxy v AstraZeneca [2011] EWHC 1831 (Pat)

The first of two judgments handed down by Mr Justice Kitchin this morning, Ranbaxy v AstraZeneca [2011] EWHC 1831 (Pat) concerns a declaration for non infringement sought by Ranbaxy in respect of its proposed importation of a product for the treatment of complaints caused by excess gastric acid.

AstraZeneca is the proprietor of a patent (EP(UK) 1 020 461) on the use of esomeprazole (right) for the inhibition of gastric acid secretion. It markets this treatment under the trade name “Nexium”. Esomeprazole is the S, or (-), enantiomer of the racemic mixture known as omeprazole (itself marketed since 1988 as “Losec”).

The patent requires the use of magnesium esomeprazole with a high optical purity (expressed in terms of enantiomeric excess (e.e.), i.e. the fraction of the compound present as the major enantiomer less the fraction of the compound present as the minor enantiomer). It was drafted in the “Swiss form”, and claims were directed to the use of magnesium esomeprazole with an optical purity of ≥ 99.8 % e.e. for the manufacture of a medicament for the inhibition of gastric acid secretion.

Ranbaxy is an importer of generic pharmaceuticals. As noted, it sought a declaration of non-infringement in respect of plans to import a pharmaceutical product that it (unsurprisingly given the nature of the declaration sought) considered did not infringe AstraZeneca’s patent. AstraZeneca, for its part, counterclaimed alleging that it did.

The product for which Ranbaxy sought its declaration was formed from a starting material of magnesium esomeprazole with an optical purity of ≥ 99.8 % e.e. To this was added a quantity of omeprazole racemate. The resultant product accordingly no longer contained magnesium esomeprazole of that optical purity.

AstraZeneca contended that this was still an infringement – arguing that the product Ranbaxy wished to import “was the direct product of a process in which magnesium esomeprazole with an optical purity of ≥ 99.8 % e.e. is used to make a medicament for the inhibition of gastric acid secretion.”

Ranbaxy, by contrast, contended for a different interpretation – arguing that the product it wished to import was not formulated using, and did not contain, magnesium esomeprazole with an optical purity of ≥ 99.8 % e.e.

It all came down to the interpretation of the claims. Claim 1 read:
“The use of a magnesium salt of (-)-5-methoxy-2[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-benzimidazole ((-)-omeprazole) with an optical purity of ≥ 99.8% enantiomeric excess (e.e.) for the manufacture of a medicament for the inhibition of gastric acid secretion.”
Ranbaxy contended that this was limited to use of magnesium esomeprazole with an optical purity of ≥ 99.8% e.e. for the manufacture of a medicament which contains magnesium esomeprazole of that purity. AstraZeneca, however, argued that this was a simple process claim and that as such, it was not limited to the manufacture of specific products but extended to the use of the claimed process to make any product. Accordingly, it stated that the claim covered use of a magnesium salt of esomeprazole with an optical purity of ≥ 99.8% e.e. for the manufacture of a medicament for the inhibition of gastric acid secretion irrespective of whether or not the medicament itself contained magnesium esomeprazole at all.

Following a rather nice potted history of “Swiss form” claims and second medical use (found between [42] and [61]), the Judge addressed the “crucial question, namely what the skilled person would have understood the patentee to be using the words of claim 1 to mean.” Diving into the specification, Kitchin J noted that the skilled person:
[67] “Recognising the teaching of the specification that magnesium esomeprazole with an optical purity of ≥ 99.8 % e.e. is new, he would nevertheless understand claim 1 to be directed to the use of such magnesium esomeprazole to manufacture a medicament which contains that active ingredient.”
This understanding would be backed up by appreciation that the claims themselves fell into various sets
[69] “Claim 1, as a Swiss form claim, and forming as it does the first of a cascade of claims directed to the use of optically pure magnesium esomeprazole to manufacture a medicament for the treatment of different or more specific uses, would … naturally be understood as requiring the medicament to contain the active ingredient for which the claimed use has been found.”
Accordingly, Ranbaxy was entitled to its declaration of non infringement and AstraZeneca’s counterclaim for infringement failed.

6 comments:

Anonymous said...

I've not yet read this decision but I am looking forward to it, particularly relating the interpretion of the scope of Swiss claims. The EPO now consider such claims to lack clarity and are no longer allowable. Mr Kitchin must have felt differently and was able to form a clear meaning.

The case appears to highlight the problem of pharmaceutical patent claims being narrower than the scope of the product covered by the approved product label. If you can work outside the patent and still produce a marketable product then the patent is of little value.

Anonymous said...

The ban on Swiss form claims was not retroactive, and thus since the patent has a priority date of 1993, the Judge has to construe it as a Swiss form claim under the old rules.

That is what happens when the parent compound patent is barely inventive (if at all) and is revoked.

You are left with a life-cycle extending narrow patent of questionable validity and, as seen here, able to be designed around.

AZ got enough of a monopoly out of this life cycle extension product to be more than happy.

For the rest of us not concerned with the inventive benefit of "decreased inter patient variability" justifying 100 times the cost, we will continue to just take two omeprazole tabs.

Anonymous said...

My comment re swiss claims is more to do with the reasoning for their recent demise. If the EPO believe they lack clarity today, then they must have always lacked clarity. Personally I don't believe they do lack clarity though I'm not sure how many decisions have needed to interpret their scope. Is this the only one?

Why take two tablets into the shower when one will do? Be nice to see what the curretn position is regarding the benefits of the single isomer over the racemate, rather than the early data used to support the patent.

Anonymous said...

G2/08 did not state that the Swiss claim was unclear, it merely stated that the question referred to the Enlarged Board in respect of the new Art.54(5) had not been clearly answered in respect of the Swiss claim as well. This decision is correct in my view, since if the claim is to be interpreted broadly as contended by AZ as formulating a composition containing any % enantiomeric purity of the active constituent, provided that a purer form is used to produce it and is then diluted by a racemate to result in an active agent of a % enantiomeric purity which has been used in the state of the art, such an interpretation would mean that the claim lacked inventive step because (i) the claim in such a broad interpretation would no longer solve the problem only solved by the higher purity and (ii) the treatment would involve using a known level of purity for treating the same disease.

Anonymous said...

The justification by the EPO for banning the use use of Swiss claims is utter nonsense. A patentee has the right to define their invention as they see fit and if a Swiss claim is of different scope to the current allowed wording, the patentee has a right to that scope

The wording of the claim was originally deemed allowable to fill the so-called lacuna, but a lacuna can only be filled by a claim whose wording has a clear meaning and scope. If the claim wording is meaningless for new applications then it must also be deemed worthless retroactively.

I have no problem with Swiss claims, but then I am not one of the current breed of the EPO who want to re-write everything to give themsleves a reason to exist. Let the EPO get back to basics and examine the applications that are clogginf up their desks.

Anonymous said...

The EPO never said that the Swiss Form was not clear.

It stated that since it was no longer needed, it would no longer be allowable to have a claim in that format to cover a further medical indication of a known compound.

The key is that the claim has to be construed to include the intended use of the medicament being manufactured as a limiting feature, otherwise it is just formulating a product known to have medical use into a medicament - which lacks novelty.

Hence, EPO policy is now that Swiss type claims post-G2/08, if directed to a further medical indication of a known drug, will refused as lacking novelty.

They will still let you have a 'Swiss' format claim if the compound is novel per se (although their internal guidance says that applicants should be advised to use the EPC2000 format instead).

It was the UKIPO, in their practice note issued shortly after G2/08, who stated that such claims would now be refused as lacking clarity - which I agree is a nonsense. If it was clear before, it is clear now.

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