In a significant decision by THE HONOURABLE MR JUSTICE KITCHIN of Court of Appeal for England and Wales on dispute between generic player Generics (UK) Ltd v Daiichi Pharma (innovator), court opined that SPC (supplementary protection certificate no. SPC/GB97/085) granted to product patent European Patent (UK) No. 0206283, which covers Levofloxacine is justified and not invalid. The ‘283 patent relates to the S (-) enantiomer of a racemic compound called ofloxacin. Ofloxacin is a member of the quinolone class of anti-microbial agents. The R (-) enantiomer of ofloxacin is known as Levofloxacin. The application for the Patent was filed on 20 June 1986 and it proceeded to grant on 27 January 1993. On 6 June 1997, UK marketing authorisations were granted in respect of Levofloxacin, subsequently, the SPC was duly granted to ‘283 patent on 13 July 1998. The Patent expired on 20 June 2006, but the SPC will expire on 19 June 2011.
The generic player Generics UK challenged the SPC of this patent First, it is said that the SPC is invalid pursuant to Article 15 of Council Regulation (EEC) No 1768/92 ("the SPC Regulation") because grounds exist which would have justified revocation of the Patent, or its limitation to the extent that Levofloxacin would no longer have been protected by the claims. Secondly, there is a free standing attack on the SPC (or its duration) based upon earlier marketing authorisations for ofloxacin.
Generic player Generics UK challenged the patent validity based on obviousness and cited following articles as prior art:
1) EP 0,047,005 ("the 005 Patent").
2) DL-8280, Drugs of the Future, vol 8, no. 5 (1983) pp. 395-396 ("Drugs of the Future").
3) EP application No. 0225552
4) An abstract entitled "Synthesis and antibacterial activity of the optical isomers of 6,7-dihydro-9-fluoro-5-methyl-1-oxo-1H, 5H-benzo[ij] quinolizine-2carboxylic acid (flumequine)" by Gerster et al, (Proceedings of the North American Medicinal Chemistry Symposium, Toronto, 153 (1982)) ("Gerster I").
5) A paper entitled "Differentiation of fluorinated quinolone antibacterials with Neisseria gonorrhoea isolates" by Rohlfing et al, (Journal of Antimicrobial Chemotherapy, 15, 539-544) ("Rohlfing").
6) A poster said to be that of Dr Gerster at the 1982 Toronto symposium to which the Gerster I abstract relates ("Gerster IP"). There is a factual issue as to whether Gerster IP was made available to the public.
7) A paper entitled "Stereochemical aspects of the antibacterial activity of S-25930" by Gerster et al, (25th Interscience Conference on Antimicrobial Agents and Chemotherapy, Minneapolis, 29 September – 2 October 1985) ('Gerster II'). Gerster II only becomes relevant if the Patent is not entitled to its first priority date of 20 June 1985.
The Court of Appeal dismissed the appeal and opined that the person having ordinary skilled in the art during development of Levofloxacin would have tried to resolve enantiomer of Ofloxacin, however, the skilled person could have tried to explore resolution up to a certain points. However, unexpected results like better solubility, lesser toxicity and decreased dose in comparison to Ofloxacin suggest that invention is not obvious and court opined that claim 1-2 and 5-7 of disputed patent are not invalid.
Opinion of court http://www.bailii.org/cgi-bin/markup.cgi?doc=/ew/cases/EWHC/Patents/2008/2413.html&query=levofloxacin&method=boolean
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