Generic challenge stands up as dosing patent flops

In a UK Supreme Court judgment, ICOS Corporation and Eli Lilly’s patent for a dosing regime for tadalafil, a second in class erectile dysfunction drug, was found to lack inventiveness.

The first medical use patent and SPC for tadalafil has expired and manufacturers were preparing to launch generic versions of tadalafil.  ICOS’s patent, exclusively licensed to Lilly, claimed dosage regimes allowing for daily dosing of a low dose of tadalafil and management of erectile dysfunction without having to utilise on demand dosing.  

Actavis brought revocation proceedings, seeking to clear the way for its own generic tadalafil. The Court of Appeal found ICOS’s patent invalid, as it was obvious in view of standard procedures in clinical trials. The notional skilled team would try to find the lowest effective dose of tadalafil and therefore there was no inventive step in this dosage regime, required for an invention to be patentable. 

The Supreme Court has upheld the Court of Appeal’s decision. Organisations such as Medicines for Europe, the British Generic Manufacturers Association, the IP Federation and the UK BioIndustry Association provided submissions to the court to reflect concerns on behalf of their members that the outcome of this judgment might mean that inventions made in the course of experiments on a patented drug would now not be patentable as they would be obvious.

However, Lord Hodge made it clear in this judgment that these types of claims would be assessed on a case-by-case basis and emphasised that the law of inventive step is there to strike a balance in the patent system.

For the moment, this means that there is no further protection for tadalafil and generics will be able to enter into this market with a daily dosage medication for patients with erectile dysfunction.