Omnipharm Ltd v Merial

In assessing obviousness, the court must decide the single statutory question whether the invention was obvious. “Obvious to try” is only one factor and requires a fair expectation of success. Where the claimed invention plausibly promises a technical effect, the question is whether achieving that effect was obvious, rather than whether it might occur.

For insufficiency, practical guidance and working examples may enable a broad claim even though further experiments are needed. But a patent is insufficient where it gives only broad component lists and an assertion of efficacy, without enough guidance to achieve the claimed invention without undue effort.

Omnipharm sought revocation of two Merial patents concerning fipronil flea treatments for pets and declarations of non-infringement. The patents were attacked for obviousness, insufficiency and added matter. Merial offered amendments, including amendments concerning spot-on formulations and the scope of “composition”.

The central issues were whether the claimed fipronil spot-on formulations and fipronil-plus-insect-growth-regulator combinations were obvious, whether the specifications enabled the inventions across their breadth, whether the amendments were allowable, and whether Omnipharm had standing to seek declarations of non-infringement.

1. Obviousness. The court applied the structured approach in Pozzoli v BDMO [2007] EWCA Civ 588; [2007] FSR 37. The inventive concept of the 881 claims was a suitable fipronil spot-on formulation, not a formulation which might work. The skilled team had motivation to investigate a spot-on, but no common general knowledge theory explaining non-systemic distribution from a point of application. Other successful spot-ons and the efficacy of fipronil did not provide a technical basis for predicting success. There was therefore no fair expectation of success, and the obviousness attack on 881 failed.
2. The 564 claims were no more obvious than the narrower 881 claims. The attack based on Donahue & Young failed because that publication concerned a different active ingredient and a spray. The court made an obiter observation that, if a suitable non-systemic formulation principle had existed, the strong rationale for combining an adulticide and an insect growth regulator might have led to a successful formulation.
3. Insufficiency. The 881 specification contained working formulation examples and sufficient practical guidance. Further experiments did not establish insufficiency. The 564 specification contained no proper formulation examples. Its general references to solvents, co-solvents and anti-nucleating agents did not guide the skilled person to success without undue effort. The 564 patent was therefore insufficient.
4. Amendments and standing. The amendments were allowable. A spot-on and a pour-on were sufficiently distinct to be understood by the skilled person. Under section 71 of the Patents Act 1977, an applicant need only propose to do the relevant act; the court need not investigate whether the proposal is settled, firm or commercially realistic.
5. Patent 881 was valid, while patent 564 was invalid. The amendments were allowed. Omnipharm was entitled to agreed declarations of non-infringement.