The present decision concerns an invention in the field of haemodialysis. It deals with the question of whether a claim comprising a step which is formulated in terms so general that it includes configurations where a therapeutic effect is obtained, may be held patentable. In other words, is the presence of a step that is potentially (but not necessarily) therapeutic sufficient to exclude a method from patentability?
Claim 1 as granted read:
Method of determining a parameter (D, K, Kt/v, Cbin) indicative of the effectiveness of an extracorporeal treatment of blood, consisting in making a patient’s blood and a treatment liquid flow one on each side of the semipermeable membrane of a membrane exchanger,
characterized in that it includes the steps of:
- making a treatment liquid flow through the exchanger, a treatment liquid having a characteristic (Cd) which has an approximately constant nominal value (CdOin) upstream of the exchanger;
- varying the value of the characteristic (Cd) upstream of the exchanger for a time tc–ta, at the end of which the characteristic (Cd) is returned to its nominal value (CdOin) upstream of the exchanger;
- measuring and storing in memory a plurality of values adopted by the characteristic (Cd) of the treatment liquid downstream of the exchanger in response to the variation in the value of this characteristic (Cd) caused upstream of the exchanger;
characterized in that it includes the steps of:
- determining the area (Sout) of a downstream perturbation region bounded by:
- a baseline passing through two values given by the characteristic (Cd) at two times flanking the perturbation, at which times the characteristic (Cd) is not, or respectively is no longer, influenced by the perturbation; and
- a curve representing the variation with respect to time of the characteristic (Cd), established from the values of the characteristic (Cd) which are measured downstream of the exchanger between two times t1 and t3 flanking the perturbation, at which times the characteristic (Cd) is not, or respectively is no longer, influenced by the perturbation; and
- calculating the parameter (D, K, Kt/v, Cbin) indicative of the effectiveness of a treatment from the area (Sout) of the downstream perturbation region and from the area (Sin) of an upstream perturbation region bounded by:
- a baseline consisting of the nominal value (CdOin) of the characteristic (Cd), and
- a curve representing the variation with respect to time, over the period tc–ta, of the characteristic (Cd) upstream of the exchanger.
[2.1] A 53 lists certain exceptions to patentability. Its paragraph c) points out that European patents shall not be granted in respect of methods for treatment of the human or animal body by surgery or therapy and diagnostic methods practised on the human or animal body.
In its opinion G 1/04 [6.2.1], the Enlarged Board of appeal has studied the question from which point on a method had to be considered as a diagnostic method practised on the human body. In this context, it has stated that methods for treatment of the human body by surgery or therapy practised on the human body [sic] had to be distinguished from diagnostic methods and that a method could fall under the exclusion provided by A 53 c) if only one of its steps were to be considered as surgical or therapeutic.
[2.2] The fundamental question under consideration is whether the method of determining a parameter claimed in the opposed patent includes a step that has to be considered as being of therapeutic or surgical nature.
The wording of claim 1 as granted does not explicitly comprise a surgical step. Therefore, the Board has concentrated on the question of whether one of the steps that are explicitly claimed had to be considered as being of therapeutic nature.
[2.3] The claimed method is a method of determining a parameter indicative of the effectiveness of an extracorporeal treatment of blood. A method of extracorporeal treatment of blood consists in making a patient’s blood and a treatment liquid flow one on each side of the semipermeable membrane of a membrane exchanger such that there is an exchange of liquids and of substances between the patient’s blood and the treatment liquid through the membrane. The treatment liquid has a composition chosen such that the composition of the patient’s blood is modified in a predetermined way. A haemodialytic treatment that allow to treat the blood of patients suffering from renal deficiency is such an extracorporeal treatment of blood. In fact the unique embodiment of the invention in the opposed patent is such a haemodialytic treatment. The dialysis liquid has several properties, and in particular a certain sodium concentration for a given conductivity.
The idea underlying the invention is to vary one of the properties of the dialysis liquid, such as the sodium concentration, upstream of the exchanger, to measure the perturbation induced downstream of the exchanger in order to be able to mathematically deduce a parameter indicative of the effectiveness of the treatment from the perturbations measured upstream and downstream of the exchanger. The practitioner or the physician then changes (or does not change) the ongoing treatment in view of a predetermined therapeutic objective as a function of the value of this parameter.
The decisive step in claim 1 under consideration thus consists in “varying the value of the characteristic (Cd) upstream of the exchanger for a time tc–ta, at the end of which the characteristic (Cd) is returned to its nominal value (CdOin) upstream of the exchanger”.
[2.4] First it has to be noted that the wording of this step does not give any information concerning the amplitude, the duration or the frequency of the induced variation. In other words, all amplitudes, durations and frequencies suitable for serving the determination of the given parameter are covered by the scope of the claim.
It is also useful to consider the teaching of D1 published in December 1994, i.e. three years before the priority date of the opposed patent. This document concerns a device that allows to avoid the problems related to hypotension which are observed for certain patients during the dialysis. More precisely, this device allows to automatically deliver a suitable dose of sodium to the patients when the first symptoms of hypotension appear, so that the hypotension is avoided. To this aim the patient presses a button when the symptoms appear and the dialysis machine automatically increases the sodium concentration of the dialysate (for example by 16 meq/l) for a predetermined duration (for example, 10 minutes […]). The increase of the sodium concentration and the duration of the application are variable and adapted to the needs of the patients […]. As a matter of fact, the [patent proprietor] has acknowledged that the injection of sodium was a common means for fighting against hypotension problems observed for certain patients during a dialysis session.
Document D1 shows that for at least certain durations and variations of the sodium concentration (which is a characteristic of the treatment liquid) there certainly is a therapeutic effect that is acknowledged in certain patients. As the wording of the contested step of the method does not contain any range of values, the execution of this step, therefore, necessarily has a therapeutic effect on the patients suffering from hypotension when the characteristic varies in the proportions and during the durations indicated in D1.
The preceding considerations are sufficient for imparting a therapeutic step within the meaning of A 53 c) and, therefore, for excluding it from patentability.
[2.5] The [patent proprietor] has acknowledged that the execution of the claimed method might have a physiological effect on the patient. However, according to it, in order for the method to be considered as therapeutic, there would have to be a therapeutic purpose, as well as a therapeutic effect. In other words, there would have to be an indication of a disease or an ill-being to be avoided or healed and a precise treatment, i.e. the injection of a well-defined component at a well-defined moment for a well-defined duration. Such an interpretation would be contrary to the principle according to which, in a claim “the general covers the specific”. The claim in its generality covers a multitude of treatment liquids, the dose, and injection times. Therefore, it also covers the case in which the chosen treatment liquid, the dose and the injection time will have a beneficial effect on a patient showing the symptoms of hypotension. In other words, the method of determining a parameter such as claimed in claim 1, that is to say, defining an indeterminate value of the variation of a characteristic of the treatment liquid during an indeterminate duration necessarily includes the case in which it will have a beneficial effect on a patient showing the symptoms of hypotension, as disclosed in D1.
The [patent proprietor] has not been able to persuade the Board that the doses and durations of application recommended in D1 could not be used in the claimed method. Quite to the contrary, the doses and durations indicated by the [patent proprietor] are of the same order of magnitude as those needed for the treatment of hypotension.
[2.6] The [patent proprietor] insisted on the fact that the doses required for the measures had no effect on the therapeutic treatment of the patient. Furthermore, the physician of a hospital using several dialysis machines having a system for measuring the dialysance based on the injection of a peak of sodium similar to the claimed one, had confirmed that these peaks of sodium had no influence on the therapy.
On one hand, the [patent proprietor] has not supplied any precise test or proof allowing to corroborate its affirmations. On the other hand, what matters is not whether the machines of the prior art sending a sodium peak to patients for reasons of measurements produce a therapeutic effect or not, nor does it matter whether there are values in the claimed range of values for which there is no therapeutic effect or even a negative effect on the patent. The question is only whether the values or the ranges of values that lead without any doubt to a therapeutic effect are covered by the wording of the claim.
As for the passage in the description of the opposed patent according to which the patient is exposed to a treatment liquid different from the prescribed treatment liquid for a very short period of time, it does not allow to affirm that no therapeutic effect is obtained. It rather indicates that if the time or exposition (cumulated or not) is badly chosen, it will necessarily have a negative influence on the ongoing haemodialysis. Moreover, the duration is not specified in the claim under consideration.
[2.7] The [patent proprietor] considers that it should not be hindered from obtaining a patent for a method including one single step that could be therapeutic because this would prevent it from suing a possible infringer whereas a physician reproducing only the critical step could not be sued for infringement anyway because he would not reproduce the method as a whole.
Even if one admits that the purpose of the exclusion under A 53 c) is to avoid that the medical corps be hindered in exercising its functions, the Board is bound by the text of the EPC. The Board is forced to recognize that through the wording of A 53 c) the legislator has not chosen to exclude only the methods that could be prescribed by a physician for a therapeutic purpose, but, more generally, methods for treatment of the human or animal body by therapy practised on the human or animal body.
To this aim, as has been stated by the Enlarged Board of appeal in its opinion G 1/04, the presence of one single therapeutic step is sufficient for excluding a method practised on the human body from patentability. Thus a method practised on the human or animal body and claimed in general terms, as in the claim under consideration, and which originally has no declared therapeutic purpose but which, under certain circumstances, inevitably generates a therapeutic effect when executed, falls under the exclusion according to A 53 c).
[2.8] The [patent proprietor] argues that A 53 c) does not contain any wording such as “relative to a therapeutic treatment” or “which are useful for the purpose of a therapeutic treatment”, which means that the claimed method should not be excluded from patentability.
The method claimed in the opposed patent cannot be considered as being merely “relative to a therapeutic treatment” as it inevitably produces a therapeutic effect in patients having symptoms of hypotension. A method for the production of one of the components of the dialysis liquid would, for instance, be a method “relative to a therapeutic treatment”. Nothing of that kind is claimed here.
[2.9] The [patent proprietor] has also pointed out that the EPO had already granted a great number of patents concerned with the determination of a parameter during a therapeutic treatment and that the Office had to remain coherent with itself and thus grant a patent.
As provided in A 23, the members of the Boards of appeal are independent in the exercise of their duties. In particular, A 23(3) states that in their decisions the members of the Boards shall not be bound by any instructions and shall comply only with the provisions of this Convention. The existence of patents granted for methods that are similar to the method claimed here, therefore, could not possibly bind the Board, even in the case where the Board departed from the interpretation or explanation of the Convention in an earlier decision of one of the Boards (see Article 20 RPBA).
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