Canada: When Two Is Better Than One: Synergistic Combination Patents

As the Supreme Court acknowledged in the 1979 decision in Monsanto v. Commissioner of Patents, citing with approval an earlier decision of the Chancery Division:

In the drug field in particular research is very expensive and the number of "winners" found is only a minute proportion of those synthesized and tested. Once a winner is found, however, it is very common also to find that bodies more or less closely related to it have the same or even greater activity . . . Unless, therefore, the original inventor . . . can properly be given reasonably broad cover, it is likely that soon after others hear of his success similar bodies will be made by others . . . [and] any reward he may obtain for his invention and research is likely to be of little value.

In other words, in life sciences research, the mythical "eureka" moment often occurs only after an enormous investment of effort and expense. Once it does, absent strong patent protection, copycats looking to capitalize on the gains of others are likely to follow.

As with any pharmaceutical invention, the discovery of a pharmaceutical combination that displays a synergistic effect (defined in the 2009 Federal Court Lundbeck decision as one in which the use of two or more compounds in a combination therapy generates a result that is greater than the sum of its parts) will often be surprising, and arise after extensive investigation. Therefore, the inventor should consider seeking patent protection not only for the "winning" synergistic combination, but also for other combinations for which a similar synergistic effect may be predicted. For example, if compounds A and B are shown to have a synergistic effect when administered together, and compounds B and C share a common characteristic, the inventor may wish to seek patent protection over the combination of both A + B and A + C. In Canada, such protection may be obtained under the doctrine of sound prediction, provided certain criteria are met by the patent application, and by the prediction itself.

Under the doctrine of sound prediction, a patent must set out (i) a factual basis for the prediction; (ii) an articulable and "sound" line of reasoning leading from the factual basis to the prediction; and (iii) proper disclosure. While case law does not clearly define what constitutes a sound prediction, the following factors have been considered:

  • Claims must be fairly based on the disclosure;
  • It must be prima facie reasonable that the patentee has a claim;
  • Prediction cannot mean a certainty; and
  • The desired result must be inferable from the factual basis.

For a synergistic combination patent, factual basis may be provided by the observed synergistic effect. Support is a matter of fact rather than degree. In the 1982 Re Lilly Industries decision, the Patent Appeal Board held that disclosure data exemplifying the synergistic effects was not explicitly required. In that case, the factual basis was limited to a statement that, ". . . it has been surprisingly found that the combinations of the invention are particularly effective . . . ". It should be noted that such an Appeal Board decision, while persuasive, would not be binding on any court, and it is generally advisable that a patent applicant disclose at least some data, if available, demonstrating the observed synergistic effect. For the "sound" line of reasoning, the disclosure may describe common characteristics between the tested combination and the other claimed combinations, e.g., common chemical structures, functions, or modes of action. A theoretical explanation as to the cause of the synergistic effect, and why it may be reasonably expected in respect of the other, untested, claimed combinations, may also be advisable.

Over the course of prosecution (or litigation), it may be advantageous for an inventor or another expert in the field of the invention to provide evidence about what was commonly known in the art at the filing date. Returning to our hypothetical scenario, having discovered the (tested and disclosed) synergistic combination of A and B, the patentee also claimed the (untested) combination of A and C. Add to this scenario the assumption that it was known, at the date of filing of the patent application, that B and C share a common characteristic (e.g., three-dimensional shape). Further assume that knowledge of this common characteristic would have led a skilled person to predict, based on the test results for A + B, that A + C would also be synergistically effective. In this case, information about commonly shared knowledge may be useful in justifying the "soundness" of the prediction. Such information may aid in persuading the Patent Office (or a court) the claims to A + C are valid.

A surprisingly synergistic combination may constitute a valuable invention worthy of patent protection. To ensure that, following the "eureka" moment of its discovery, the inventor is rewarded with the broadest scope of patent protection possible, careful consideration of Canadian patent law particularities and practice should be taken in preparing the patent application, and carrying it through examination before the Patent Office.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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