INDUSTRY TALK
Is your future dosage patent vulnerable to 'obviousness'?
Inventing dosage regimes is a crucial and lengthy step in drug development. Patenting dosage is even trickier. Subsequent to the UK Supreme Court’s ruling on the Tadalafil patent, Spoor & Fisher’s Tertia Beharie shares insight into the implications of the obviousness argument on dosage patents.
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atent (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.
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
familiar pre-clinical and clinical procedures. It would have been ‘very likely’ the skilled research team would have conducted further testing at lower doses, including five
The patent is owned by ICOS and exclusively
blanket prohibition on such patents when
milligrams, which the experts suggested
licensed to Eli Lilly. Tadalafil (branded as
drafted in the corrected format.
would have been a ‘no brainer’.
CIALIS) is an orally administered drug for treating erectile dysfunction (ED). It works
The obviousness argument
Implications for SA
in a similar way to Pfizer’s blockbuster drug
Considering the 10 steps, the UK Supreme
The patent for Tadalafil has also been
Viagra, but with fewer side effects. UK
Court found the patent ‘obvious’. The
filed in South Africa and is set to expire in
1 173 181 relates to a dosage regime
obviousness argument was based on a
2020. While it’s unlikely the patent will be
for Tadalafil.
prior art patent application (WO 97/03675)
challenged locally, the stringent 10 step
known as Daugan, which disclosed the use
approach might be used as a blueprint
milligrams of Tadalafil up to a maximum total
of Tadalafil for the treatment of ED, giving
and influence South African Courts in
dose of five milligrams per day.
a 50mg dose as a formulation example.
assessing the inventive step for future
The patent claims doses of nought to five
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
The 10 step approach might be used as a blueprint and influence South African Courts
• was the research routine in nature
dosage patent cases. The judgement also begs the question – when are dosage patents considered inventive? Given the long list of factors a court might consider, it appears a dosage patent could be more vulnerable to an obviousness attack, not just in the UK but worldwide. Dosage patents can still be valid and a worthwhile means of protecting continuing research on a known drug. Yet patent applicants should focus on any unusual features in their research programme and emphasise these
• the burden and cost of the
Daugan specified a Tadalafil dose in the
research programme
range of 0.5 to 800mg per day. Daugan also
• what value judgments would the
provided data for a 50mg Tadalafil dose.
no doubt reconsider their future global
research team have to make
Daugan did not disclose a dose of one to
patent filing strategies for dosage patent
• were there alternative paths
five milligrams per day of Tadalafil as an
applications, as a result of this judgment. •
of research
effective treatment of sexual dysfunction.
• the motivation of the skilled person to
The novelty of the subsequent Tadalafil
undertake certain technical trials • were the results unexpected or surprising – the court did caution that the fact routine
patent in view of Daugan was therefore not at issue. The Court confirmed the skilled team
tests have uncertain results, does not turn
would use routine, established practices
those results into an invention
involved in pharma research, and the
• the need to avoid hindsight – was
Daugan patent would have motivated them
the combination of steps by which
to identify the low dose. The skilled person
the inventor arrived at the invention
generally aims for a dose as low as possible,
ascertained by hindsight knowledge
consistent with effectiveness and with regard
• whether the feature of the claimed
where possible. Multinational pharma companies will
ABOUT THE AUTHOR
Tertia Beharie is a patent attorney and an attorney of the High Court of South Africa. She specialises in filing applications in the chemical, pharma, petrochemical, agrochemical, metallurgical and biochemical fields.
for safety and tolerability, via routine and
P C Review | JULY 2019 |
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