Teva Pharmaceutical Industries Ltd. v Istituto Gentili Spa& Ors

A patent claim is not inventive merely because it identifies an untested member of a known class where the prior art discloses relevant structure–activity relationships, the compound has a reasonable prospect of biological activity, and testing is straightforward. Later publications cannot retrospectively alter what was obvious at the priority date.

A Swiss-type claim directed to a new dosing regime may nevertheless be, in substance, a method of treatment where the therapeutic use is known and the alleged novelty lies only in the manner of administration. Such a claim is excluded by section 4(2) of the Patents Act 1977, and section 4(3) does not save it where the claim also covers known dosage forms.

Three generic drug companies sought revocation of two patents concerning alendronate, an aminohydroxybisphosphonate used to inhibit bone resorption. The first patent claimed pharmaceutical compositions containing alendronate or a related compound, including oral compositions. The second patent claimed the use of alendronate in a 70 mg once-weekly osteoporosis dosing regime.

The court considered novelty and obviousness over several items of prior art. It also considered whether the second patent’s Swiss-type claim was excluded as a method of treatment of the human body by therapy, and whether known 10 mg and 40 mg tablets anticipated the claim.

1. Both patents were invalid. The claims of the first patent were anticipated or obvious. The claim of the second patent was excluded as a method of treatment and was also anticipated by the known dosage forms.

2. The skilled team in 1982 could include a medicinal chemist. The skilled person was entitled to take up the prior art and do what it made obvious. Common general knowledge included the clinical use of bisphosphonates in treating disorders involving excess bone destruction.

3. The disclosure in Blum, General Tire and Kabachnik was sufficient to disclose pharmaceutical use of the relevant compounds. A pharmaceutically acceptable carrier or diluent was the ordinary consequence of preparing a pharmaceutical composition with an active ingredient. The relevant claims were therefore anticipated or lacked inventive step.

4. The Fleisch article disclosed useful structure–activity relationships: an amino group and hydroxyl group enhanced activity, and increasing chain length could increase activity. It was obvious to try longer-chain analogues of pamidronate. The exercise involved only a small number of compounds and available testing methods. A mechanism of action did not need to be understood before a rational structure–activity investigation could be undertaken.

5. Evidence and publications after the priority date could not establish that an earlier invention was unobvious. Nor did an unproved assumption that activity would decline linearly between compounds justify declining to test alendronate.

6. The second patent claimed a dosing regime, not merely a 70 mg dosage form. It could be practised using several known forms, including seven 10 mg tablets, a liquid dose, or probably two 40 mg tablets. Applying the binding majority approach in Bristol-Myers Squibb v Baker Norton, the claim was in substance to a method of treatment because the known drug and therapeutic purpose were unchanged and the alleged novelty lay only in the dosing method. Section 4(3) did not save the claim.

7. The known 10 mg and 40 mg forms also anticipated the claim because the only relevant difference was the administration instruction. The claims were accordingly revoked, and both patents were held invalid.