A recent High Court decision ( WEHC 1831(Pat)) has considered the scope of the European
“Swisstype” second medical use claim. These claims are embedded in European practice through
EPO Enlarged Board of Appeal decision G5/83 and take the form: “x for use in the manufacture of a
In the present decision (Ranbaxy (UK) Limited and AstraZeneca AB), Ranbaxy sought a declaration
of non infringement and revocation of EP patent number 1 020 461, owned by AstraZeneca.
The Patent covers one of AstraZeneca’s drugs called Nexium which is used to treat gastric acid re-
lated disease. The active ingredient of Nexium is magnesium esomeprazole, the magnesium salt of
the S enantiomer (the (-) enantiomer) of the racemic mixture known as omeprazole which was itself
introduced onto the market under the brand name Losec in 1988.
Claim 1 of the patent is in “Swiss form” and is 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
There was no dispute that Ranbaxy’s process of manufacture begins with magnesium esomeprazole
with an optical purity of ≥ 99.8% e.e. There was also no dispute that the process involves the addition
of a quantity of omeprazole racemate such that the finished product no longer contains magnesium
esomeprazole of that optical purity.
AstraZeneca’s case was that Claim 1 is a process claim which is infringed if a magnesium salt of
esomeprazole with an optical purity of ≥ 99.8% e.e. is used for the manufacture of a medicament for
the inhibition of gastric acid secretion irrespective of whether or not the medicament contains magne-
sium esomeprazole at all. They argued that the product which Ranbaxy wishes to import is the direct
Ranbaxy said it is not infringing because, on a proper interpretation, Claim 1 is directed to the 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.
Thus, the whole issue turns on the proper interpretation of claim 1. The Court went on to consider
what the skilled person would have understood the patentee to be using the language of the claim to
The skilled person must be taken to know the basic drafting conventions used to frame a patent and
its claims. The judge (The Hon. Mr Justice Kitchin) said that EPO Decision G5/83 embodied the form
of Swiss type claims in EPO practice and indicated that he thought it is inherent in the reasoning of the
this decision that the skilled person would generally understand a Swiss form claim to mean that the
medicament must contain the active ingredient for which the new and inventive use has been found.
But for the exclusion contained in Article 52(4) EPC 1973, the claim would have been directed to the
new and non obvious use of that ingredient.
He did not go so far as to suggest that a claim cast in Swiss form must always be construed as be-
ing directed to the use of an active ingredient for the manufacture of a medicament which contains
that ingredient. However, he did say said that the skilled person would appreciate that to construe
it otherwise would render the claim vulnerable to an attack of insufficiency. He noted that in this
case there is no suggestion anywhere in the body of the specification of the provision or use of any
analogue of derivative of magnesium esomeprazole or, indeed of any other active ingredient for
the treatment of gastrointestinal disorders or any other condition. The whole teaching of the speci-
fication is about the production of optically pure magnesium esomeprazole and its use in particular
therapies and, for that purpose, its formulation with a conventional carrier.
Ranbaxy was therefore entitled to its declaration of non infringement.
Swiss-type claim vs. EPC2000 purpose limited product claim
The patent also contained a corresponding EPC2000 purpose limited product claim: “a magne-
sium salt of esomeprazole with an optical purity of ≥ 99.8% e.e. for use in inhibiting gastric acid
secretion”. The judge commented on the overlap between the Swiss-type claim on the one hand
and the EPC2000 claim on the other. Does the Swiss-type claim capture a product (as a direct
product of the claimed process) that the EPC2000 product claim does not? In this case, the judge
answered “no”. Kitchin believed the skilled person would believe the patentee has simply seized
the opportunity afforded under the EPC 1973 and the EPC 2000 to include both types of claim.
This is an interesting point and one upon which even the EPO does not seem sure of its position.
In the EPO Official Journal, Special Edition 4, 2007, it was said that the protection conferred by an
EPC 2000 purpose limited product claim is equivalent, as far as the further uses are concerned,
to that offered by the Swiss type claim. However, in Enlarged Board of Appeal decision G2/08, for
example, the Enlarged Board said that it appears that the rights conferred on the patentee by the
EPC 2000 purpose limited product claim are likely broader. Further, Technical Boards of Appeal
are not allowing a change of claim category from the Swiss-type claim to the EPC 2000 purpose
limited product claim in post-grant opposition proceedings as offending provisions relating to im-
permissible extension of protection (A123(3)EPC), (T 250/05). In view of this divergence, a referral
to the Enlarged Board might be expected.
For now, our advice is to continue to include both types of claim for applications where one is en-
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