Patents – whether correct to revoke on novelty grounds

Synthon BV v SmithKline Beecham plc [2003] EWCA Civ

SKB was the proprietor of a patent in respect of an invention entitled ‘paroxetine salt’. The patent was filed in April 1999 with a priority date of 2 July 1998. Synthon BV was the applicant for a patent filed in June 1997 for an invention entitled ‘4-phenylpiperidine compounds’. It was not published until 17 December 1998. Synthon started proceedings seeking revocation of SKB’s patent alleging that it was not new at its priority date having regard to what was disclosed in the Synthon application. That was an appropriate allegation as s2(3) of the Patents Act 1977 required the application to form part of the state of the art for the purposes of considering whether the SKB patent was novel. The patent claimed paroxetine methane sulfenate (PMS) as a novel compound and the specification gave general directions for the preparation of crystalline PMS. The claims in the Synthon application did not mention PMS, although it fell within the generality of the formulae. No claim was made to a crystalline form. The only relevant mention of PMS was in an experiment. The issue before the judge was whether the patent was new having regard to the description in the application. The judge concluded that the two inventors had disclosed the same invention at the same level of generality and that Synthon was first, so that the patent was not new and he ordered its revocation.