Court Of Appeal Confirms Invalidity Of Patent For EXELON Because It Was Obvious To Resolve Racemate Using Standard Techn

Novartis AG v. Generics (UK) Limited (t/a Mylan) [2012] EWCA Civ 1623

The Court of Appeal has upheld the High Court's ruling that Novartis AG's patent covering a (-)-enantiomer was invalid for obviousness.

Background

The Patent (UK Patent No. 2,203,040 and associated SPC) covered the chemical rivastigmine, which Novartis markets in the UK as Exelon for the treatment of Alzheimer's disease. Rivastigmine is composed of a (-)-enantiomer1 and, at the priority date, a racemic compound containing rivastigamine (-) enantionmer had already been disclosed in two prior publications which had identified RA7 as a potential treatment for Alzheimer's disease but did not suggest the compound should be resolved into its individual enantiomers.

Generics had applied to revoke the Patent. The High Court held that it would have been obvious to a skilled team working in the pharmaceutical industry at the priority date of the Patent (1987) to select RA7 for development, to separate RA7 into its enantiomers and to use the (-)-enantiomer for the treatment of Alzheimer's disease. The Patent and associated SPC were therefore found to be invalid.

The Law

Section 3 of the Patents Act 1977 states that an invention involves an inventive step "if it is not obvious to a person skilled in the art, having regard to any matter which forms part of the state of the art".

The Courts have recently cautioned against substituting a test such as "is it obvious to try" for the statutory test in section 3. However, it has also been acknowledged that, in certain circumstances, the "obvious to try" formula can sometimes be useful in determining the obviousness question, particularly if there is a reasonable or fair expectation of success within a reasonable timeframe (eg Kitchin LJ in Medimmune Ltd v Novartis Pharmaceuticals UK Ltd & Ors [2012] EWCA Civ 1234).

The Dispute

Novartis contended that the High Court had incorrectly used the "obvious to try" test and had not considered whether there was a fair expectation of success. At the priority date, it was not obvious: (i) to stop the process of Weinstock's investigations and move a compound into development; (ii) to try the (-)- enantiomer for a particular therapeutic purpose.

The Respondent, however, argued that Novartis was simply inviting the court to reverse the judge's evaluation of the facts.

The Decision

The Court of Appeal held that in deciding whether an invention was obvious to the skilled but unimaginative addressee at the...