2.5.3.3.5 "Obvious to Try"

The High Court in Aktiebolaget Hassle v Alphapharm Pty Ltd [2002] HCA 59; (2002) 212 CLR 411 endorsed the “Cripps question” approach to obviousness:

"Would the notional research group at the relevant date, in all the circumstances, which include a knowledge of all the relevant prior art and of the facts of the nature and success of chlorpromazine, directly be led as a matter of course to try the -CF3 substitution in the '2' position in place of the -CI atom in chlorpromazine or in any other body which, apart from the -CF3 substitution, has the other characteristics of the formula of claim 1, in the expectation that it might well produce a useful alternative to or better drug than chlorpromazine or a body useful for any other purpose?"

This can be simplified to:

Would the person skilled in the art (in all the circumstances) directly be led as a matter of course to try the claimed invention in the expectation that it might well produce a solution to the problem?

This approach is only appropriate when there is a problem to be solved, being either a problem that is recognised in the art or a problem that is reasonably inferred from the specification. Where the invention lies in the identification of the problem, the “obvious to try” approach will not be appropriate.

It should be noted that “obvious to try” is qualified by the requirement that there is a reasonable expectation that the solution might well solve the problem.

When applying this test, examiners need to appreciate that there will often be many possible solutions to a problem. Not all solutions can be regarded as obvious. Some possible solutions will be likely to solve the problem, while others will be highly speculative. The question that needs to be considered is whether there is a reasonable expectation that the solution will solve the problem.  

The reasons why there would be a reasonable expectation could be:  

• the solution is known in analogous systems;
• the art is highly predictable; or
• the prior art teaches that the solution will work, although it has not been confirmed in an example.

The reasons should be provided in support of the objection, e.g.

“The problem relates to identifying compounds with antibacterial activity. The citation teaches that compounds of formula II will have antibacterial activity, although there are no examples confirming this prediction. In light of this disclosure, it would have been obvious to try compounds of formula II in the expectation that they would have antibacterial activity.”