Is your future dosage patent vulnerable to ‘obviousness’?

Patent (UK 1173 181) for the drug Tadalafil has been ruled as invalid by the UK Supreme Court, on the basis it lacked an inventive step. The patent is owned by ICOS and exclusively licensed to Eli Lilly. Tadalafil (branded as CIALIS) is an orally administered drug for treating erectile dysfunction (ED). It works in a similar way to Pfizer’s blockbuster drug Viagra, but with fewer side effects. UK 1 173 181 relates to a dosage regime for Tadalafil.

The patent claims doses of nought to five milligrams of Tadalafil up to a maximum total dose of five milligrams per day.

In an attempt to clear the market for their own Tadalafil generic, Actavis and other generic companies brought revocation proceedings against the ICOS/Lilly patent.

The case concerns a principle question – how does the test of obviousness apply to a dosage patent?

To clarify the theory behind the inventive step, the UK Supreme Court provides guidance in a 10 step approach.

The following factors have to be considered in the obviousness assessment:

• was it obvious to try

• was the research routine in nature

• the burden and cost of the research programme

• what value judgments would the research team have to make

• were there alternative paths of research

• the motivation of the skilled person to undertake certain technical trials

• were the results unexpected or surprising – the court did caution that the fact routine tests have uncertain results, does not turn those results into an invention

• the need to avoid hindsight – was the combination of steps by which the inventor arrived at the invention ascertained by hindsight knowledge

• whether the feature of the claimed invention is an added benefit in which the claimed innovation is obvious for another purpose

• in the case of a dosage patent, there is no blanket prohibition on such patents when drafted in the corrected format.