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Velocys Inc v CompactGTL Limited, UK Patents Court, 22 September 2014, [2014] EWHC 2951 (Pat)

This case raises some unusual issues regarding patent amendment.  Velocys, an exclusive licensee, alleged infringement of two European patents, EP (UK) Nos. 1 206 508 and 1 206 509.  The patents were almost identical specifications but with different claims and related to catalysts for use in the Fisher-Tropsch process.

A key feature of claim 1 of the 508 patents was a “feed stream having a residence time within said catalyst structure less than 5 seconds”.  Velocys applied to amend the patent.  In the amended claim “residence time” was replaced with “contact time”.  Velocys also applied to make a similar amendment to the 509 patent.  Unusually the grounds for the amendment was that the reference to “residence time” was an obvious mistake.  Both parties were agreed on the law: unless the references to “residence time” were an obvious mistake, amending those references to “contact time” would add matter and extend the protection conferred by the patent, with the result that the patent would be invalid.  To succeed Velocys therefore had to show that the skilled person would (i) immediately appreciate that the reference to “residence time” was not intended, and (ii) unequivocally ascertain that the patentee meant to refer to “contact time”.


After analysing the disclosure of the patent and the evidence of the expert witnesses, the judge (Arnold J) held that the mistake was indeed obvious to the skilled man, as was the correction to contact time.  He therefore permitted the amendment. 

Velocys also applied to add new dependent claims to both patents and argued that they should be permitted to make these amendments even if the independent claims on which the new claims depended were held to be valid.  The judge disagreed: EPO practice did not allow new dependent claims in such circumstances to be added in opposition proceedings and the same principle had been applied previously to national amendment applications in the UK.  The judge therefore refused to allow these amendments as the new dependent claims were unnecessary if the independent claims were valid. 

Finally, the judge did hold that the independent claims were valid (and infringed).  CompactGTL alleged that they were anticipated and obvious over certain prior art.  On the facts the judge found that the anticipation attacks failed.  Obviousness was alleged over international patent application WO98/38147 (“Schanke”).  The judge held that, for a number of reasons, Schanke would not have been regarded by the skilled person as a good starting point.  Even if the skilled person had used Schanke as a starting point, it would still not have been obvious.

Read the judgment here.

Headnote: Graham Burnett-Hall, Marks&Clerk Solicitors