"Obvious to try" is obviously not obvious

What is left of the Johns-Manville “obvious to try” inquiry? That is the question raised by last month’s decision from Mr Justice Floyd in Omnipharm Ltd v Merial [2011] EWHC 3393 (Pat). The patents in issue relate to treatments for protecting pets or small mammals from fleas. The main claim of interest, claim 1A of Merial's European Patent (UK) 0 881 881 claimed a “spot on” formulation of fipronil for the treatment of fleas. In a “spot on” treatment the insecticide is dabbed on a small area of the animal’s body, usually near the shoulder blades, and then spreads over the animal’s body to kill the fleas. The closest prior art was Merial’s own “Frontline” product, a "spray on" fipronil treatment, which, since its launch roughly a year before the priority date of the 881 patent “rapidly became recognised as a very effective product, better than anything else on the market” [23].

How do fleas and insecticide ever manage to meet?

The crucial question was whether a spot on formulation was obvious over a spray on formulation. Mr Justice Floyd held that because a spot on formulation was easier to apply than spray on formulation, “there was a motivation for the skilled team at least to ask itself whether a spot-on formulation of fipronil could be made.” However, there was no satisfactory theory of how or why spot on treatments worked. It was a mystery as to how the active ingredient spread itself over the animal’s body. Consequently, it could not be predicted in advance whether any particular insecticide would work in a spot on formulation. This Kat imagines the following conversation at Merial, which is consistent with Floyd J’s findings:

          “We’ve had a great success with the fipronil spray. Should we try it as a spot on?”
          “Certainly. It’s not as messy as a spray, and pet owners like it better.”
          “Will it work?”
          “No way to tell with these things. We’ll just have to try it and see.”

A few weeks later:

“How did it go.”

“No problem. Had to mess around a bit to get the right excipients, but that wasn’t too much trouble.”

Though it was obvious to try, and there was no evidence of difficulty in achieving success, Floyd J nonetheless held the formulation to be not obvious. The key point was that “[t]he skilled team would have no basis for predicting that that result could be achieved” [124].

Certainly this reasoning is supported by the authorities cited by Floyd J at [85]-[89], to the effect that even though an invention is obvious to try, it is nonetheless obvious only if it is “more-or-less self-evident that what is being tested ought to work” (Lord Justice Jacob in St Gobain v Fusion Provida [2005] EWCA Civ 177 [35]) and there must be a “fair expectation of success” (Lord Hoffmann in Conor v Angiotech [2008] UKHL 49 [42].)

This doctrine has gotten a bit hairy

But if this is right, then what is left of Johns-Manville's Patent [1967] RPC 479? As I understand it, that case is directed exactly at those situations where success cannot be predicted in advance, yet the invention is obvious to try and succeeds without difficulty once tried. The claim was to a flocculating agent (which causes separation of suspended solids) for use in production of asbestos cement. It was well-known that a flocculating agent that would not weaken the cement would be desirable, but none had previously been found. The flocculating agent in question had recently been developed and used with success in other industries, so it was held to be obvious to try them in making asbestos cement. There is no suggestion in that decision that it could be predicted with any particular expectation of success that the flocculating agent in question would work, apparently because the question of whether the agent would weaken the cement was a question which could only be answered by experiment. The patentee’s argument was precisely that the invention was only obvious if success could be predicted in advance (485), and this was the test that was rejected by the Court of Appeal. Diplock LJ stated, “I think that ‘would be’ puts it too high if it postulates prior certainty of success before actually testing the polymers in the filtration process; it is enough that the person versed in the art would assess the likelihood of success as sufficient to warrant actual trial.” There was no discussion of the particular level of success in Johns-Manville; the point was that it was obvious to try, and once tried, succeeded without difficulty, and that was enough for it to be obvious.

In this Kat’s view, Johns-Manville was rightly decided. In an “obvious to try” scenario we may ask two questions: Was the invention obvious to try? If so, was it also obvious to succeed? Asked this way it would seem the invention is not obvious to succeed if success cannot be predicted in advance, no matter how obvious to try and how easy the success. But the equivalent questions framed in terms of inventive step are slightly different: Was there an inventive step in deciding to try the invention? Was there an inventive step involved in bringing the invention to success, once tried? The reformulation makes no difference to the first question, but to ask whether there was an inventive step, rather than whether the invention would obviously succeed, means that success need not be predicted in advance, so long as the trial itself did not require ingenuity or experimentation deserving of a patent reward. This is essentially the view of Judge Birss QC in Molnlycke Health Care AB v Brightwake Ltd [2011] EWHC 376 (Pat) [301] in the course of finding the invention obvious: “So the product is obvious to conceive but it would remain a mere proposal unless the skilled team can actually make it without the exercise of invention.”

No doubt is it wrong to say that simply because an invention is obvious to try and it in fact succeeds once tried, it is therefore obvious. There may be an inventive step in achieving success. That, in this Kat’s view, is the important clarification of Johns-Manville that is reflected in cases such as Saint-Gobain and Conor v Angiotech. In Saint-Gobain there was secondary evidence that pointed strongly to non-obviousness [23], and in Conor v Angiotech there were a large number of drugs which could be tried [41], which distinguishes them from Johns-Manville on their facts. But Omnipharm v Merial is very difficult to distinguish from Johns-Manville. In Johns-Manville the question was whether a new flocculating agent should be tried for cement. In Omnipharm the question was whether a new spray on flea treatment should be tried in a spot on formulation. In both cases the invention was obvious to try. In neither cases was inventive ingenuity necessary for success. Is Johns-Manville sound in principle? This Kat believes it is. Would Johns-Manville be decided the same way today? This Kat is not so sure.