The plausibility of second medical use inventions - why is it necessary?
In the Supreme Court decision, Lord Sumption began his discussion of plausibility by considering the problem raised by determining the sufficiency of Swiss-style second medical use claims.
An armchair inventor |
Positive and negative plausibility
Warner-Lambert argued that the lessons to be taken from T 609/02 were that it is necessary for the patentee to disclose reasons regarding the claimed therapeutic effect as plausible only when the skilled person reading the patent would be skeptical about it in the absence of such a disclosure ("negative plausibility"). However, Lord Sumption thought that, whilst this reading was consistent with the turns of phrase in the case, "it would have been a strange thing for the Technical Board of Appeal to have meant". This was because it would be inconsistent with the whole reason behind the necessity of the plausibility test: "it would mean that if nothing was known either for or against the claimed therapeutic effect, no disclosure need be made in support of it". Lord Sumption thus interpreted the principle laid down by T 609/02 as being that "the specification must disclose some reason for supposing that the implied assertion of efficacy in the claim is true" (paragraph 36) ("positive plausibility").
Lord Sumption's reading of T 609/02 was key to how he decided on the appropriate requirements for plausibility. However, other judges voiced some concern with the reasoning.
Following the standard interpretation of T 609/02 as requiring negative plausibility, does it follow that in a case where nothing is known either for or against a claimed effect, no disclosure need be made in support of it? Some would argue that, on the contrary, that in the empirical sciences completely new assertions (i.e.those lacking any evidence either way for their truth) must be backed-up with some form of empirical evidence before they are considered remotely plausible. In fact, the more disconnected an assertion is with that which has gone before, the greater the need for evidence. Negative plausibility thus may not enable someone to claim something for which there is no evidence whatsoever. Lord Sumption's interpretation of the EPO approach to plausibility is therefore controversial.
Plausible over the entire scope of the claim?
However, it could be argued that the distinction is perhaps not quite as clear as it first appears. If a patent specification provides data demonstrating that a drug only works in 95% of patients suffering from HIV infection, following the Supreme Court's reasoning, it is sufficiently disclosed for a drug for use in the treatment of HIV infection. However, the reason the treatment does not work in the 100% of HIV patients will be due to differences in the underlying pathology of the disease, the mechanisms of which have just not been identified.
By contrast, if a patent specification only provides data showing that a drug works with respect to patients shown to have HIV-1 infection (e.g. representing 95% of HIV infections) but is not sufficiently disclosed with respect to the treatment of HIV-2, it is not enabled across the entire scope of a claim to a drug for use in the treatment of HIV. The patent would only be sufficiently disclosed for a drug use in the treatment of HIV-1.
The only difference between the former and latter examples is that in the latter the reason for the drug not working in all patients (95% of patients versus HIV-1 but not HIV-2 infected individuals) is known. It can be asked therefore, whether there is a distinction between a treatment that only treats a proportion of patients suffering from a condition and a treatment that only treats a sub-type of patients suffering where the condition? (except that the sub-type has been identified).
Personalized medicine takes these issues to the extreme. In personalized medicine, conditions can be said to embrace an ever increasing number of causative pathologies, potentially each unique to an individual. Whilst this is an extreme example, it demonstrates that achieving plausibility for the use of a drug to treat a disease having potentially many distinct (and as yet potentially unknown) underlying mechanisms of pathology may not be a trivial task. It also raises the question of how the plausibility test should be applied when the the distinct causative pathologies are identified after the filing date for a patent application.
What about first medical use claims?
Lord Sumption appears to restrict the plausibility test to second medical use claims. This seems to be because he believes the invention underlying a first medical use patent to be the provision of the compound, as opposed to it use in a treatment. However, an inventor could make a new (but e.g. obvious) compound and speculatively claim from the comfort of their armchair that it could be used to any number of diseases. Following Lord Sumption's logic for the need for the plausibility test, should the specification of a patent claiming a first medical use also be required to make the assertion plausible to all conditions falling under the scope of the claim? Particularly, if in a hypothetical world, the patent in suit was the first to disclose pregabalin, and included a broad claim to the use of pregabalin in the treatment of pain, would this be deemed sufficiently disclosed?
However, Lord Sumption argued that just because central sensitization may be involved in both peripheral neuropathic pain and inflammatory pain “does not prove that they have a common cause” and “does not suggest that there may be a common metabolic mechanism at work”. [the phrase "metabolic mechanism" is quoted from the TBA law, but does not make sense in this context; "common mechanism of action" may have been a better choice of phrase].
Lord Sumption disagreed with the Court of Appeal that the plausibility test could be satisfied by “the slimmest of evidence” from which a therapeutic effect could be plausibly predicted. Lord Sumption instead identified the principle as being that “the specification must disclose some reason for supposing that the implied assertion of efficacy in the claim is true”. Given that “the specification in the present case says nothing about neuropathic pain of any kind”. Furthermore, the specification did not refer to the central sensitization as a mechanism of action of the drug, "there is nothing to suggest, even as a hypothesis, that pregabalin works with peripheral neuropathic pain by blocking central sensitisation". Additionally, whilst the specification provides mouse models that may be used to test for the efficacy of a drug in peripheral neuropathic pain, it does not directly suggest doing so.
Lord Sumption thus ruled that the requirement for plausibility was not satisfied, as the specification did not provide a full disclosure of its contribution to the art: "The disclosure did not contribute any knowledge of the art capable of justifying a claim to a monopoly of the manufacture of pregabalin for the treatment of neuropathic pain of any kind".
By requiring explicit disclosure of a mechanism of action of a claimed therapeutic effect that is predictive across the entire scope of the claim, Lord Sumption therefore arguably establishes a prima facie test for the plausibility of the therapeutic efficacy of a composition. This test seems to go beyond that usually applied by the EPO, in that positive reasoning is required as to why the claimed effect is plausible given the data provided in the specification.
Lord Hodge and Lord Mance
Has the right balance been struck?
The disagreement among the Judges on whether negative or positive plausibility should be the test for second medical use claims, has been reflected in the responses to the decision since it was handed down. There are diverging opinions as to whether the Supreme Court (and particularly Lord Sumption) places the bar for plausibility too high. Is the requirement for positive reasons for the plausibility of a claimed therapeutic effect necessary to prevent speculative inventors obtaining unfair monopolies? Would the EPO's test for negative plausibility have ensured that the right bargain had been struct between the patentee and the state?
In the follow-up next post on the case, IPKat will look at the court's reasoning on the issue of infringement.
How terrible it is that an inventor should need to provide positive evidence of actually having invented something prior to being awarded a monopoly for 20 years that can stymie any R&D in that area! I think that some perspective is needed here. It is still a very low bar - there just need be some tangible reasoning disclosed. The other route would constitute a charter for trolling...
ReplyDeleteThe question relating to an HIV treatment is interesting.
ReplyDeleteTo my mind, if an application claims a drug for treating HIV and doesn't acknowledge the existence of the two different types of HIV or differentiate between the efficacy of the drug for the two different types then the application is insufficient for both types of HIV. This is extremely basic information that has to be included in a patent application. In the absence of this information the skilled person would likely consider the specification to be extremely deficient and would not consider anything disclosed therein to be plausible (even if it actually works).
This, again, is a very low bar that could be overcome by a simple paragraph stating "There are two types of HIV: HIV-1 and HIV-2, these are believed to have different underlying pathologies. It is currently believed that the drug is effective in treatment of both types."
Interesting summary - thanks. Is there an authority for saying "Following the STANDARD INTERPRETATION of T 609/02 as requiring negative plausibility" and "Would THE EPO'S TEST FOR NEGATIVE PLAUSIBILITY have ensured that the right bargain had been struct between the patentee and the state" (my emphasis)? I'm not sure most EPO practitioners would characterise the approach of the EPO in this way. Personally, I think the EPO tends to require what this summary calls "positive plausibility", although there are of course variations between Divisions and Boards.
ReplyDeleteIf one would follow Warner-Lambert’s line of argumentation it would boil down to, in case of a first or further medical indication, that by merely alleging some medical effect without the faintest proof of it, be it empirical or not, a patent should be granted. This is anything but reasonable.
ReplyDeleteI cannot see that the standard interpretation of T 609/02 is requiring “negative plausibility”, the contrary seems true. If as an applicant you allege some medical effect, you have the onus of proof.
For the disclosure to be sufficient in this matter, it is important for the applicant/proprietor to show that at the priority/filing date the originally filed documents render it plausible that the patent is solving the problem stated, i.e. to be effective in the treatment of a given illness or to have the desired effect on the metabolism.
T 609/02 is only one of a long list of decisions relating to plausibility in case of medical uses. T 488/16 (dasatinib) is another decision of the same kind. See also T 866/08, T 1050/12 or T 1255/11.
The only valid plausibility is a “positive plausibility”. It is only if plausibility is positively given at the priority/filing date that post-published documents can be taken into account. This seems plainly logical and it is difficult to see anything controversial in it.
When disclosing plausibility, it does not mean that plausibility at filing should only be required in case of a second medical use. It applies as well to a first medical use. I would simply say that it is even more important in a second medical use that the pathology treated is different and that there is a least some reasonable likelihood, that it works.
A patent can only be granted if there is a contribution to the existing art. And this has to be demonstrated at priority/filing, hence the quest for plausibility. That not every pharmaceutical has a positive effect on a human body is a mystery which might never be solved, but it has at least to be made plausible.