Prior disclosure

3.11 It would be sufficient to prove that a prior art discloses an invention, if the matter relied upon as prior art discloses subject matter which, if performed, would result in infringement of the patent (a “reverse infringement” test) as set out by the Court of Appeal in General Tire & Rubber Company v Firestone Tyre & Rubber Company Limited [1972] RPC 457 and followed in Muhlbauer AG v Manufacturing Integration Technology Ltd [2010] SGCA 6:

“If the prior inventor’s publication contains a clear description of, or clear instructions to do or make, something that would infringe the patentee’s claim if carried out after the grant of the patentee’s patent, the patentee’s claim will have been shown to lack the necessary novelty, that is to say, it will have been anticipated. The prior inventor, however, and the patentee may have approached the same device from different starting points and may for this reason, or it may be for other reasons, have so described their devices that it cannot be immediately discerned from a reading of the language which they have respectively used that they have discovered in truth the same device; but if carrying out the directions contained in the prior inventor’s publication will inevitably result in something being made or done which, if the patentee’s patent were valid, would constitute an infringement of the patentee’s claim, this circumstance demonstrates that the patentee’s claim has in fact been anticipated.”

3.12 In Merck & Co Inc v Pharmaforte Singapore Pte Ltd [1999] SGHC 323, the plaintiffs argued that any prior art that is relied on to destroy novelty must unequivocally point to the invention and must not merely be a signpost on the path to discovering the invention. Lai Kew Chai J in delivering the judgment of the High Court agreed that in order for anticipation to arise, the prior art must disclose to a notional instructed reader essential integers to the invention as claimed.

3.13 The provision of novelty therefore involves a consideration of whether the prior art discloses all of the features of the claim in question. In general a a prior disclosure will destroy the novelty of a later claim only if it discloses each and every feature specified in that claim. If the claim contains technically equivalent or additional features, then an objection of obviousness would be more appropriate.

3.14 However, a purposive construction of a claim may indicate that one or more features do not materially affect the working of the invention – in effect they are non-essential. In such rare occasions an objection of lack of novelty may be warranted. For example if the invention consists of a known drug in a package together with instructions for usage, an objection of lack of novelty based on a document disclosing the known drug in a package with the same manner of usage may be appropriate, since the feature of the written instructions merely makes explicit the presence of insturctions describing the known manner of usage, but does not materially affect the working of the invention – that is, the biological effect of the active ingredient.

3.15 A disclosure which is capable of being carried out in a manner which falls within the scope of the claim, but is also capable of being carried out in a different manner, does not anticipate – although it may form the basis of an obviousness objection. This was noted in General Tire as follows:

“If, on the other hand, the prior publication contains a direction which is capable of being carried out in a manner which would infringe the patentee’s claim, but would be at least as likely to be carried out in a way which would not do so, the patentee’s claim will not have been anticipated, although it may fail on the ground of obviousness. To anticipate the patentee’s claim the prior publication must contain clear and unmistakable directions to do what the patentee claims to have invented … A signpost, however clear, upon the road to the patentee’s invention will not suffice. The prior inventor must be clearly shown to have planted his flag at the precise destination before the patentee”.

3.16 In discussing this judgment in SmithKline Beecham Plc’s (Paroxetine Methanesulfonate) Patent [2006] RPC 10, Lord Hoffmann added:

“But the infringement must not merely be a possible or even likely consequence of performing the invention disclosed by the prior disclosure; it must be necessarily entailed. If there is more than one possible consequence, one cannot say that performing the disclosed invention will infringe. The flag has not been planted on the patented invention, although a person performing the invention disclosed by the prior art may carry it there by accident or (if he is aware of the patented invention) by design. Indeed it may be obvious to do so.”

3.17 Thus, as Lord Hoffmann summarised the disclosure requirement as follows:

“Anticipation requires prior disclosure of subject-matter which, when performed, must necessarily infringe the patented invention.”