Astellas Pharma Industries Limited v Teva Pharmaceutical Industries Limited & Ors

A patent claim may define a broad class by structural and functional features where the specification gives a reasonable basis for expecting the invention to work across that class. Plausibility is assessed by identifying the claimed class, determining what it means for the invention to work, and asking whether success across substantially the whole scope can reasonably be predicted.

Patent claims are construed purposively and objectively. Defined expressions in the specification must be given effect where the skilled team would understand them to form part of the patentee’s chosen lexicon. In assessing obviousness, routine empirical development may be obvious, but a route to the claimed result cannot be selected by hindsight or mere chance.

Astellas alleged that generic mirabegron products proposed by Teva and Sandoz infringed EP(UK) 2,345,410, a patent concerning modified-release pharmaceutical compositions intended to reduce food effects. Teva and Sandoz counterclaimed for revocation on grounds including insufficiency, obviousness and added matter.

The principal issues were the construction of the expression “pharmaceutical composition for modified release”, whether the claims were insufficiently broad, whether the claimed formulation was obvious over Fix, Michel and Chapple, and whether the Sandoz product infringed. Teva’s original product was admitted to infringe; infringement of Teva’s revised product was not tried.

1. Construction. The expression “a pharmaceutical composition for modified release” in claim 1 was construed by reference to paragraphs [0022] and [0023] of the specification. The claim therefore required some more-than-minimal reduction in the relevant food-effect measure, although no particular percentage reduction was required. The dissolution definition in paragraph [0025] was also used in paragraph [0022] and was reflected in the claim. This was the natural purposive construction of the patentee’s defined terminology.
2. Insufficiency. The reasonable-prediction approach requires identification of the claimed class, identification of what it means for the invention to work, and assessment of whether success across substantially the whole class can reasonably be predicted. The patent disclosed a sufficient basis for predicting that formulations satisfying the claimed structural and dissolution requirements would maintain absorption beyond the food-effect period and reduce the food effect. The arbitrary nature of the boundaries did not itself establish insufficiency because the patent’s promise was delivered within those boundaries.
3. Obviousness. Fix disclosed both controlled release capable of functioning through the gastrointestinal tract and reduced food effects. It did not teach that food-effect reduction necessarily depended on colonic release. The Skilled Team would investigate the OCAS approach using routine formulation work, but none of the proposed routes to a formulation within claim 1 was obvious without hindsight. The same conclusion applied to Michel, whether read alone or with Chapple. On Astellas’ rejected alternative construction, however, the claim would have been obvious.
4. Infringement and orders. EP410, as unconditionally amended, was valid but not infringed by the Sandoz product because Astellas had not demonstrated the required reduction in food effect. Teva’s original product infringed by admission. Infringement of Teva’s revised product remained to be determined. The parties were directed to arrange a hearing on the form of order if necessary.

This was a first-instance decision of the High Court (Patents Court). The judgment records earlier litigation concerning EP(UK) 1,559,427 and its appeal, but those proceedings concerned a different patent and are not the decision under appeal in this case.