Merck & Co Inc v Generics (UK) Ltd

Patent claims are construed objectively from the language used, particularly the claims, read in the context of the specification. The Protocol permits protection for variants which the skilled reader would conclude, with reasonable confidence, that the patentee intended to cover. It does not authorise the court to enlarge the monopoly merely because a variant takes the benefit of the inventive contribution. The Improver questions are useful tools, but are not a rigid checklist or a substitute for the Protocol. Experiments may inform the factual background, but they cannot determine construction. Where it is not apparent that a claim limitation was unintended, the limitation remains effective. Clear and specific process integers could not be replaced by broad alternatives where the patent gave no reasonable basis for doing so.

The claimant sought a declaration that products made by the defendant’s confidential Indian manufacturing process infringed claims 1 and 2 of a patent for making alendronate. Validity was challenged by counterclaim, but that issue was stayed. The trial therefore concerned only construction of the process claims.

The defendant’s process differed from the claims in several respects, including the absence of methanesulphonic acid, different neutralisation and crystallisation conditions, and different collection and purification steps. The central issue was whether those differences were immaterial variants within the scope of the claims under the Protocol on Interpretation of Article 69 of the European Patent Convention.

1. Construction. The claims and specification were clear and contained no relevant technical ambiguity. The patent was to be read by the notional skilled reader, treating the patentee as skilled in the art. The court’s task was to determine objectively what exclusive rights the patentee intended to claim, with reasonable certainty for third parties. The Protocol did not permit protection to be extended merely because the variant made use of the patent’s alleged inventive contribution.
2. Variants and the Improver approach. The three Improver questions are normally useful tools, but they are not a rigid checklist and cannot replace the Protocol. If the structured approach is used, question 3 is the decisive construction question. Questions 1 and 2 may provide factual background, but do not justify experiments to determine the scope of the monopoly. Unless it is apparent that a claim limitation cannot have been intended to exclude a minor variant, the limitation remains effective.
3. Application. The reference to methanesulphonic acid could not be expanded to cover other sulphonic acids. The skilled reader could not conclude with reasonable confidence that the patentee intended that result. Nor could the precise neutralisation, cooling, filtration, washing and drying integers be replaced by unspecified alternatives. The patent presented these features as an interacting package directed to high purity and high yield, and gave no basis for identifying the extent of any wider monopoly.
4. The evidence did not establish that the defendant’s alternative acid would achieve the same high purity and yield, or that the claimed process would remain a one-pot process. The defendant’s process therefore fell outside the claims. Products made by that process did not infringe.
5. Case management. It was disproportionate for a straightforward construction issue to generate a four-day trial costing more than £850,000. The court should control evidence, experiments, disclosure, cross-examination and timetables under the overriding objective. Experiments directed to Catnic-type construction questions should not be conducted without informed prior permission. The Patents Court’s streamlined procedure could be imposed by the court where appropriate.