UK: H. Lundbeck A/S v (1) Norpharma Spa (2) Infosint S/A: Prior use right and failure to register assignment of patent in UK [2011] EWHC 907 (Pat)

03 May 2011

Gerry Kamstra

In his judgment of 14 April 2011 Mr Justice Floyd had (in addition to the usual patent infringement and validity issues) to deal with two slightly unusual questions: Namely the application of the prior use right (under section 64 Patents Act 1977) to a number of the chemical processes used over the years by Lundbeck and its suppliers; and the application of restrictions on relief to Infosint (under section 68) for failure to register the assignment in the UK of the patent in suit. The patent (EP(UK) 1,118,614) claimed “A process for the preparation of 5-carboxyphthalide [5-cbx] … in an open and however not pressurised reactor which comprises adding formaldehyde and terephthalic acid … to fuming sulfuric acid containing 20-33% by weight of SO3, heating the mixture at 120-145oC and isolating the [5-cbx] thus obtained”. 5-cbx is a chemical intermediate used in the manufacture of Lundbeck’s anti-depressant drug citalopram and the proccedings were commenced by Lundbeck, for revocation of the patent.  In the event the judge found the patent invalid for obviousness, but given the likelihood of an appeal (and potential reversal of this finding) he nevertheless dealt with the section 64 defence and the restrictions on damages and recovery of costs under section 68.

Section 64 gives the right to continue to do acts which were done in good faith in the UK before the priority date.  The judge considered some 10 processes for the synthesis of [5-cbx] which had been used by Lundbeck companies and their suppliers over the years, which were operated at various temperatures and atmospheric conditions and with different levels of SO3 in the sulphuric acid (oleum).  Of these, 5 of the processes fell within the requirements of the claim.  Of these 5 “infringing” processes 2 (the “low temperature” processes) were used before (and after) the priority date and benefited from the section 64 defence. The other 3 processes were developed by Lundbeck to avoid infringement of the patent and involved the use of two more reaction vessels (rather than one) in the belief that such “two pot” processes would not infringe the patent (which Lundbeck conceded at trial was a mistaken belief). There were two arguments for the judge to consider in relation to such “two pot” processes: First were they in substance the same as the “low temperature” processes used before the priority date, so that the importation of citalopram made by these processes should benefit from the section 64 defence in relation to infringement of the patent’s process claim ? Second, if a section 64 defence applies to these processes does it apply to the importation of the specific enantiomer escitalopram (as opposed to the importation of the racemic mixture citalopram that had gone on since before the priority date) ?  The judge held that the two pot processes were not in substance the same as the processes used before the priority date, so that the section 64 defence did not apply to them; and that the importation of escitalopram is not substantially the same act as the importation of citalopram, so this would not benefit from a section 63 defence either. As noted above however the patent had been held invalid anyhow, so there was no infringement.

Section 68 provides that where a party becomes the owner of a patent and the patent is subsequently infringed the Court will not award (A) damages or an account of profits or (B) costs or expenses unless the assignment is registered with the Patent Office within 6 months of its date or the Court is satisfied that that it was not practicable to register the assignment before then (note that section 68 was amended on 29 April 2006, so that the text at (A) applied until then and the text at (B) applies since then).  The assignment of the patent to Infosint was dated 22 July 2002 (shortly after grant to Norpharma) but was not registered with the UK Patent Office until after the proceedings were commenced by Lundbeck in 2010 (which is why Norpharma were a party to the action) – it appears that the UK patent attorneys instructed by Infosint did not expressly request the Patent Office to register a change of proprietorship as well as a change of agents on the record.  Infosint argued that the registration of that change of ownership at the European Patent Office had legal effect in the UK for the purposes of section 68, but this was rejected by the judge as the UK Act only has a provision that treats registration at the EPO of an application for a patent as registration at the UK Patent Office – there is no provision in the Act that treats registration of a transfer of ownership of a granted patent at the EPO as registration at the UK Patent Office.  The judge also found that there it was practicable to register the assignment within 6 months.  So, had the patent been valid and infringed the Court would not have awarded Infosint damages or costs.