Merck Sharp & Dohme Corp v Teva UK Ltd

For inventive-step purposes, the relevant state of the art is fixed at the priority date under the Patents Act 1977. There is no express or implied deadline within which the skilled person must complete routine testing. Time needed for routine experiments, or for regulatory approval, does not make an otherwise obvious invention inventive.

A structured account of the skilled person’s reasoning is not hindsight merely because it identifies several known matters. The question is whether the prior art would motivate a skilled team to undertake the relevant project with a fair expectation of success, using routine work rather than invention. Commercial unattractiveness, including the absence of prospective patent protection, is irrelevant to that inquiry.

Merck owned a patent concerning ophthalmic formulations combining dorzolamide and timolol for glaucoma treatment. An abstract published six days before the priority date disclosed consecutive administration of the two drugs and a clinically significant additive reduction in intraocular pressure.

Teva sought revocation. Floyd J held the patent invalid for obviousness, including as proposed to be amended, and revoked it: [2009] EWHC 2952 (Pat). Permission to appeal confined Merck to amended claim 18, a process claim requiring a co-formulated solution adjusted to pH 5.5–6.0. The central issue was whether the skilled team, starting from the prior art, would arrive at that formulation without invention.

1. Appeal dismissed unanimously. The Chancellor, with whom Richards and Patten LJJ agreed, upheld Floyd J’s conclusion that amended claim 18 lacked an inventive step. The added-matter objection therefore did not require determination.

2. Under Patents Act 1977, ss 2(2) and 3, novelty and inventive step are assessed by reference to matter publicly available before the priority date. The statutory test imposes no further time requirement. If the claimed invention is obvious from that art, it remains obvious even though routine tests would take longer than the interval between publication and the priority date. Regulatory approval work is likewise irrelevant. Merck’s time-based submission was not raised below, lacked evidential support, and was legally wrong.

3. The judge’s reasoning did not involve impermissible hindsight. The supposed multiple steps mostly described separate elements of the known state of the art. In substance, the skilled team would first embark upon a co-formulation project suggested by the prior art and then conduct routine tests to identify the necessary pH adjustment.

4. The evidence justified the findings that the prior art’s twice-daily additive results and the patient-compliance advantage would strongly motivate the skilled team, with a fair expectation of success. Discovering that lower pH was needed to dissolve sufficient dorzolamide, and investigating the limited possible effect on timolol bioavailability, would not cause the project to be abandoned. The relevant inquiry was inventive step, not whether the project would be commercially attractive or patentable.

• Court of Appeal (Civil Division) Dismissed Merck’s appeal and upheld the finding that amended claim 18 was obvious: [2011] EWCA Civ 382.
• Chancery Division, Patents Court Floyd J held the patent, including as proposed to be amended, invalid for lack of inventive step; dismissed the amendment applications and ordered revocation: [2009] EWHC 2952 (Pat).