Some pharma cases are somewhat delicate to discuss in a blog post.
Case in point, if I provide the commercial name of the drug at stake in today’s litigation, I am afraid that this post may be classified as a spam and may thus never reach my email subscribers.
You see, it is the sort of drug which is prescribed for the treatment of erectile dysfunction, and which keeps coming up in these pestering unsolicited email messages that you may receive on a daily basis.
Just to be clear, today’s drug-which-must-not-be-named is not the famous one that starts with a V (containing sildenafil as an active compound), but the other famous one that starts with a C (containing tadalafil as an active compound).
Icos Corporation (of the Eli Lilly group) is the owner of a number of European patents in connection with the C. drug.
First, there is EP 0740668, which was the basic patent for a French Supplementary Protection Certificate (SPC No. FR 03C0017), which expired in November 2017. Second, there are EP 1173181 and EP 1200092, designated as “secondary patents” by the Paris Tribunal de grande instance (TGI).
In November 2014, generic drug company Mylan obtained a marketing authorization (MA) related to the C. drug. In January 2016, Mylan initiated nullity proceedings with respect to the EP’181 and EP’092 patents in front of the Paris TGI. The parties later reached a settlement agreement with respect to EP’092, so that only the fate of EP’181 remained to be decided upon. Icos Corporation and the French distributor Lilly France counterclaimed for infringement of EP’181. The first instance judgment was issued in May 2018.
EP’181 or equivalents thereof were or are also litigated in other countries. According to the summary provided by the court, the patents were revoked in Germany, the United Kingdom, Canada and Japan. It may thus come as little surprising that the same outcome was achieved in this country. On the other hand, the ground for nullity that the TGI took into consideration is relatively unexpected, as will be apparent below.
But before getting there, let’s first look at the statute of limitations defense raised by Icos.
Mylan argued that the statute of limitations is not applicable to patent nullity suits. This argument was rejected by the court, in keeping with earlier decisions.
Turning to the determination of the starting point for the limitation period, the court recalled its now established principle of an in concreto determination.
The court thus explained that the grant of the EP’181 patent was not the starting point for the limitation period. The general principle is the following:
The starting point for the limitation period must thus be set at the date, determined in concreto, at which Mylan was or should have been aware of EP’181, due to its intent to market a generic of the drug [C.], which led to the MA obtained on November 21, 2014, since this patent is an impediment to its exploitation.
In this case, a determining factor to be taken into account was the date at which Icos obtained its own MA:
In this case, the first MA for [C.] was granted in November 2002. By way of application of article R. 5121-28 of the Code de la santé publique, the generic company can only apply for an MA as from the eighth year after the grant of the originator’s MA, and cannot be granted one before the tenth year. Therefore, Mylan could not file an MA application before November 2010.
This reasoning is fully consistent with that applied in another recent case which already involved Mylan.
However, this is not the end of the story here. The court further held:
In this case, an additional fact should be taken into account in the in concreto analysis of standing and the starting point for the limitation period. […] [Namely, Icos corporation] filed a request for limitation of the EP’181 patent on February 14, 2014 with the European patent office, and the limitation of the patent was published on March 25, 2015.
Thus the patent enforceable against Mylan could only be known on this date, so that the starting point for the limitation period is March 25, 2015.
In another recent case, the starting point of the limitation period was postponed by a court to the date of the decision of the Board of appeal of the EPO in the opposition appeal regarding the patent at stake. The relevant paragraph of this decision may be worth quoting again here:
[…] It is only on [July, 7, 2014, i.e. the date of the Board of appeal’s decision] that the drafting of the patent which is sought to be revoked was stabilized and that Ethypharm was able to precisely know the content of the claims of said patent as well as all the facts making it possible for them to act, so that the action is not time-barred and is admissible.
We now have a confirmation that limitation proceedings, just like opposition proceedings, may result in a postponement of the limitation period for nullity actions.
It remains to be seen how general this principle is and in particular whether it extends e.g. to the impact of other lawsuits involving third parties.
Turning now to the merits of the case, claim 1 of EP’181 as limited reads as follows:
A pharmaceutical unit dosage composition comprising 1 to 5 mg of [tadalafil], said unit dosage form suitable for oral administration up to a maximum total dose of 5 mg per day.
Independent claim 10 is a Swiss-type claim containing similar features.
Mylan raised all classical grounds for nullity, but the court focused on insufficiency of disclosure.
After reviewing the description of the patent, the court noted the following facts:
- There are several molecules belonging to the class of type 5 phosphodiesterase (PDE5) inhibitors.
- Among them, particular reference may be made to sildenafil, the active compound of V., marketed at the priority date of the patent in doses of 25, 50 and 100 mg.
- However, sildenafil generates a number of side effects, such as facial red patches, or a lowering of blood pressure.
- The invention thus relates to a low dosage of the known alternative drug tadalafil, in order to provide an effective treatment of erectile dysfunction without the side effects associated with sildenafil.
- The patent also contains a number of examples showing the efficacy and the absence of side effects of low dosage forms of tadalafil.
The court was apparently quite puzzled by the patent as a whole:
The problem expressed in the description of the patent is to provide a principle which avoids the issues of red patches and side effects of sildenafil by a particular dosage of tadalafil.
Indeed, and as rightly noted by Mylan, no side effect associated with tadalafil is mentioned in the patent, so that the dosage suggested for tadalafil curiously addresses a problem associated with another active compound.
The court then referred to a standard mentioned in the so-called “finasteride” judgment of December 6, 2017 by the Cour de cassation, commented on this blog:
[…] When a claim relates to a [second] therapeutic application of a substance or composition, obtaining this therapeutic effect is a functional technical feature of the claim. Therefore, in order to meet the requirement of sufficiency of disclosure, it is not necessary to clinically demonstrate this technical effect; but the patent application must directly and unambiguously reflect the claimed therapeutic application, so that the skilled person can understand, based on commonly accepted models, that the results reflect this therapeutic application.
The court then came back to the technical problem presented in the patent:
Icos Corporation and Eli Lilly do not dispute that no prior art document describes any side effect related to the use of tadalafil.
And they cannot validly argue that the absence of documentation in this respect does not amount to the absence of a problem, because the onus is on them to show that there was a problem to be solved and that it is solved by the teaching of the patent.
It thus appears that the problem described in the patent relates to sildenafil and not tadalafil, and it cannot be extrapolated that both active compounds have the same side effects, unless one were to admit the resolution of artificial or speculative problems.
In fact, the examples cited in the patent demonstrate that the dosage mentioned in the patent does not address the listed “problems”.
In summary, the problem to be solved cannot be considered as the reduction in the side effects of tadalafil, because such side effects were not known in the prior art – only side effects of sildenafil were known.
Most of the examples of the patent also do not demonstrate the existence of side effects of tadalafil associated with higher dosages, so that these were held not to “reflect” the alleged therapeutic application (using the wording of the Cour de cassation).
The conclusion reached by the three-judge panel will not doubt cause a stir, as the invention recited in claim 1 was found not to be sufficiently disclosed in the patent.
The finasteride case related to a second therapeutic application invention, for a known molecule. It is well accepted both at the EPO and in French national courts that the new therapeutic application has to be demonstrated in a plausible manner in the patent, otherwise the patent is insufficient.
Yet, in the present case, claim 1 is a classical product claim, with no functional feature. According to EPO case law, there should be no problem of insufficiency of disclosure, because the skilled person is able to manufacture the composition containing the active substance at stake in the claimed dosage range. The question of whether said claimed dosage range provides any technical benefit or not only pertains to the appraisal of inventive step.
Now, as regular readers of this blog are well aware, the French approach to validity is much more fluid than the EPO’s.
If a court is convinced that an invention does not properly solve the alleged technical problem, or that the technical problem is artificial, this can give rise to a number of invalidity objections, including insufficiency of disclosure. My understanding is that the technical problem tends to be viewed by French courts as an integral part of the claimed invention itself.
But there is yet another cause for controversy in the judgment.
I mentioned above that most of the examples of the patent do not demonstrate the existence of side effects of tadalafil associated with higher dosages. That said, there is one example, namely example 7, which does analyze in detail the occurrence of various side effects depending on the dosage of tadalafil. The table of results is in fact even reproduced in the judgment. The court first remarked that some side effects are not present at all at any dosage. So far so good. But, regarding those side effects which are indeed shown to be less frequent in the claimed dosage range than at a higher dosage, the court noted:
Regarding headache, back pain and myalgia […], the reasoning is the same because these effects were never previously observed.
This part of the judgment seems to imply that, at least in the context of drug dosage patents, the existence of the technical problem to be solved must be acknowledged in the prior art, and cannot be demonstrated for the first time in the patent itself.
The invention can thus not be a so-called “problem invention“.
Things should be put into perspective, though, and the present case may not necessarily be generalized. Maybe the court did not believe that example 7 was convincing at all. At the very least, the fact that the dosage originally claimed in the patent, namely from 1 to 20 mg, had to be later restricted to 1 to 5 mg, due to some relevant prior art, certainly contributed to the court’s perception of the patent being invalid.
In fact, the court reviewed all the following claims and concluded that they suffered from the same deficiencies as claim 1, mentioning a lack of inventive step in passing for some of them. Fluidity of the grounds for nullity indeed.
As a final note, this is probably one of the last judgments penned by Ms. Courboulay, who, given her seniority and her involvement in many conferences and events, was often considered as the leading judge in the 3rd (IP) chamber of the Paris TGI.
Ms. Courboulay has now officially retired; but given the large number of important rulings which she authored, there is little doubt that her influence will continue to be felt in the coming years.
CASE REFERENCE: Tribunal de grande instance de Paris, 3ème chambre 1ère section, April 5, 2018, Mylan v. Lilly France & Icos Corporation, RG No.16/05073.