Omnipharm Ltd v Merial

A patent is insufficient if its specification, read with common general knowledge, gives the skilled person no sufficient practical guidance to work the invention across the claim’s breadth without undue effort. Detailed worked examples are not invariably required. Their absence may nevertheless be decisive where a broad claim to a technically difficult formulation provides only general lists of ingredients and an unworkable theory, leaving the skilled person to undertake empirical research.

An appellate court will respect a trial judge’s multi-factorial evaluation of insufficiency unless an error of principle or perversity is shown. A discretionary costs order will likewise stand where the judge has fairly assessed the parties’ substantive commercial success and the overlap between the issues.

Omnipharm sought revocation of Merial’s patents for spot-on fipronil formulations for pets and declarations that its proposed products did not infringe. The Patents Court upheld the amended 881 patent, but held the 564 patent invalid for insufficiency because it claimed a fipronil and insect-growth-regulator combination without practical formulation guidance. It also ordered Merial to pay 40% of Omnipharm’s costs.

Merial appealed the invalidity finding and the costs order. Omnipharm advanced contingent cross-appeals on obviousness, which were not argued after the court indicated that the insufficiency finding would be upheld. The central issue was whether the 564 specification enabled the skilled team to formulate products throughout the claims without undue effort.

The court dismissed Merial’s appeal against the invalidity of the 564 patent and against the 40% costs order. It allowed Merial the costs of its applications to preserve security for costs pending the appeal.

1. The judge had not treated the absence of detailed examples as an independent legal requirement. Rather, he had found that the 564 specification gave only broad lists of active ingredients, solvents and excipients. It contained no worked formulation of the claimed two-active spot-on product. In the circumstances, it gave no real practical assistance beyond common general knowledge and left the skilled team to find a successful combination by empirical effort.
2. The evidence supported that conclusion. The skilled team did not possess an accepted theory explaining non-systemic distribution, did not know which formulation tools would achieve it, and faced a materially harder task in formulating two active ingredients together. The 564 patent was therefore insufficient because it did not enable the claimed invention across its breadth without undue effort.
3. The court gave appropriate respect to the judge’s multi-factorial evaluation of insufficiency, consistently with the appellate restraint described in Biogen v Medeva [1997] RPC 1. No error of principle or evidential deficiency had been shown.
4. The claims did not require either systemic or non-systemic distribution. That point did not assist Merial, because sufficiency depended on whether the claimed formulations could be made without undue effort, whatever their mechanism of distribution.
5. Applying the principles governing review of discretionary costs orders, including Adamson v Halifax [2003] 1 WLR 60, the court held that the judge was entitled to regard Omnipharm as the overall winner. It had cleared the way for three proposed formulations and obtained freedom to market combination products, despite Merial’s important success in maintaining the 881 patent. The overlap between obviousness and insufficiency justified treating the 564 challenge as a genuine squeeze and supported the 40% order.
6. Omnipharm should have offered its satisfactory undertaking about security earlier. Merial was therefore entitled to the costs of the later security applications, to be set off against Omnipharm’s costs of the substantive appeal.

• Court of Appeal (Civil Division): Dismissed Merial’s appeals against the invalidity of the 564 patent and the 40% costs order; awarded Merial the costs of its applications concerning security pending appeal: [2013] EWCA Civ 2.
• High Court, Chancery Division, Patents Court: Floyd J upheld the amended 881 patent, revoked the 564 patent for insufficiency, granted declarations of non-infringement for three proposed formulations, and ordered Merial to pay 40% of Omnipharm’s costs: [2011] EWHC 3393 (Pat).