Vericore Ltd v Vetrepharm Ltd & Anor

In construing a patent claim expressed in Swiss form, the expression “for the treatment of” means “suitable for” that treatment. A claim to the use of an emulsified concentrate therefore covers a concentrate capable of producing either an emulsion or a suspension in the treatment medium, where the specification and examples support that construction. An amendment cannot be allowed if the amended claims encompass subject matter already invalid for lack of novelty or obviousness. A skilled person’s assessment of obviousness is objective and excludes personal preferences or dislikes. A warning in prior art that a formulation can be toxic will not deter the skilled person where it falls short of a firm teaching against testing the otherwise obvious formulation.

Vericore sought to amend the claims of patent GB 2,270,261 after the Patent Office held that the original claims lacked novelty and were obvious. The appeal against that decision had been dismissed, and permission had been given to apply for amendment.

The proposed principal claim concerned the use of a pyrethroid pesticide to manufacture an emulsified concentrate for treating sea lice in seawater fish. The central issues were whether the claim was limited to treatment by an emulsion in seawater and, if so, whether that subject matter was inventive over the cited prior art.

1. The amendment application was refused. The proposed claims covered products capable of generating a suspension of pyrethroid in seawater. That construction followed from the ordinary meaning of “for” as “suitable for”, the wording of the claim and the specification’s examples.
2. The reference to an emulsified concentrate described an intermediate formulation. It did not require the pyrethroid to remain in emulsion form when the fish were treated. The examples used emulsified concentrate mixed with ethyl alcohol before introduction into seawater, where the pyrethroid precipitated as fine solid crystals and formed a suspension.
3. Because the proposed claims included treatment by suspension, they encompassed subject matter already found invalid. The application to amend was therefore refused.
4. Alternatively, if the claim were confined to use of an emulsion in seawater, it would still lack inventive step. The skilled addressee would regard an emulsion as the obvious delivery vehicle for a compound of very low water solubility. The passages in D2 and D9 did not provide a sufficiently firm warning to deter that course, and the skilled person would also consider synthetic pyrethroids.
5. The assessment was objective. Applying the approach stated in Pfizer Ltd’s Patent [2001] FSR 201 at paragraph 62, the notional skilled person did not possess the personal preferences or dislikes of an individual witness. The separate delay argument and the added-matter argument did not require determination.

1. Patent Office: The Divisional Director, acting for the Comptroller, held on 18 March 2002 that the original claims lacked novelty and that the claims were obvious. Permission was given to apply for amendment.
2. High Court (Patents Court): The appeal against that decision was dismissed on 6 February 2003. The present court refused the subsequent application to amend.