High court rules in generics uk (mylan) v novartis [2011] ewhc 2403 (pat) - rivastigmine spc/gb98/038 and its basic patent uk patent no 2 203 040

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High Court Rules in Generics UK
(Mylan) v Novartis [2011] EWHC 2403 (Pat)
Rivastigmine SPC/GB98/038 - and its
basic patent UK Patent no 2 203 040
The High Court has recently handed down judgment resulting in the revocation of the Novartis patent and
SPC relating to rivastigmine (Exelon®). This is a further action where the Court was faced with a patent
relating to the resolved enantiomer of a prior art racemic compound. Unlike the previous occasions, the
evidence presented was supportive of the conclusion that it would have been obvious for the skilled person
to have resolved the prior art racemic compound.
Rivastigmine is an acetylcholine esterase approved for the treatment of dementia/Alzheimer’s Disease. It is
the (-) enantiomer of a compound disclosed in EP0193926A (Weinstock) and a subsequent paper by the
same group. Novartis developed the racemic compound by resolution to identify the preferred enantiomer
and took this compound through clinical development. The patent in suit claimed priority from an application
filed in March 1987.
The parties acknowledged the previous cases decided by the UK courts on similar issues and the judge,
Floyd LJ, correctly stated that the case must be decided on its own facts. The judgment therefore includes
no analysis of those earlier cases.
Weinstock (the patent disclosure and paper) described a genus of phenyl carbamate compounds that, other
than in one possible embodiment, all possessed a chiral dialkylaminoalkyl substituent. Of the compounds
identified as being preferred, all possessed a chiral center, there was no data presented on the one achiral
derivative.
There was a difference of opinion between the expert medicinal chemists on whether the skilled person
would have directly resolved the most active compound (RA7) or first conducted a more detailed
structure/activity analysis of the generic class disclosed involving the synthesis of further derivatives
including the achiral compound.
The judge concluded that while conducting a more detailed analysis was always an option, it did not exclude
the resolution of RA7 from the realms of being an obvious step to take. The Weinstock disclosures were
taken as providing sufficient promise to render the further development of RA7 as obvious. It was not denied
that the synthesis of further compounds could also have unearthed improved derivatives but this would not
render the further development of RA7 as inventive.
The court then considered the rationale for resolution and whether there was an expectation of improved
properties. Here the difference in the experts' approach was that GUK’s expert, taking a practical approach,
described resolution in such circumstances as simply being “good science”, whereas Novartis’s expert
preferred to undertake a theoretical study for potential benefits before proceeding with the resolution. In
particular, as he could not have foreseen any potential for improvement through resolution, he would not
have resolved.
The court established that there was reason to resolve, if not for improved potency, which in this case was
acknowledged as not resulting in an improved therapeutic window, but for at least the 'practical benefits' of
avoiding potential side effects arising on drug metabolism.
In reaching this conclusion the judge noted that Novartis had not argued that the resolution itself was
potentially problematic and therefore a barrier to resolution.
D Young & Co LLP is a limited liability partnership and is registered in England and Wales with registered number OC352154. A list of members of the LLP is displayed at our registered office and on our list of members page within this website. Our registered office is at 120 Holborn, London, EC1N 2DY. D Young & Co LLP is regulated by the Intelectual Property Regulation Board. Copyright 2011 D Young & Co. All rights reserved. ‘D Young & Co’, ‘D Young & Co Intelectual Property’ and the D Young & Co logo are registered trade marks of D Young & Co LLP. This article is designed to provide information in respect of D Young & Co's intel ectual property services. Nothing in these pages constitutes legal or other professional advice and does not take into account individual circumstances and may not reflect recent changes in the law. For advice in relation to any specific situation, please contact our specialist advisors. This case provides an excellent example of how case-specific facts influence the overall decision. In contrast to the decisions in escitalopram (Generics v Lundbeck [2009] UKHL 12, difficulty to resolve and relevant dates) and levofloxacin (Generics v Daiichi [2009] EWCA Civ 646, acknowledged facts in a specific area of antibiotic chemical development), the judge found no reason to conclude that the resolution of RA7 would not have been undertaken with an expectation of success in the sense of improved properties. D Young & Co LLP is a limited liability partnership and is registered in England and Wales with registered number OC352154. A list of members of the LLP is displayed at our registered office and on our list of members page within this website. Our registered office is at 120 Holborn, London, EC1N 2DY. D Young & Co LLP is regulated by the Intelectual Property Regulation Board. Copyright 2011 D Young & Co. All rights reserved. ‘D Young & Co’, ‘D Young & Co Intelectual Property’ and the D Young & Co logo are registered trade marks of D Young & Co LLP. This article is designed to provide information in respect of D Young & Co's intel ectual property services. Nothing in these pages constitutes legal or other professional advice and does not take into account individual circumstances and may not reflect recent changes in the law. For advice in relation to any specific situation, please contact our specialist advisors.

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