T 0044/12 - No medical method

Key points

• The Board rejects the argument that a method of detecting an occlusion in a downstream fluid line of a medical pumping system is not excluded from patentability by Article 53(c) EPC. In the claimed method, the downstream fluid line is configured to carry fluid under pressure between a fluid source and a patient.
• The Opposition Division and the respondents/opponents considered that the step "initiating the pumping sequence to cause the fluid to flow into the fluid line" of claim 2 was a therapeutic step because it changed the patient's status through the injection of medicine.
• The Board is of the opinion that " the subject-matter of claims 1 and 2 falls within the definition of methods only concerning the operation of a device"  of G 1/07.

EPO T 0044/12 - link

V. Claims 1, 2, 21 and 40 of the main request as filed on 8 August 2016 read as follows (additions over version as granted underlined):

"1. A method of automatically detecting an occlusion in a downstream fluid line (22) of a medical pumping system (10), the downstream fluid line (22) being configured to carry fluid under pressure between a fluid source (13) and a patient (24), the method comprising:
during a pumping sequence, determining a first force value indicative of force in the downstream fluid line (22) at time T1;
during the pumping sequence, determining a second force value indicative of force in the downstream fluid line (22) at time T2; and
providing an indication of the occlusion in the downstream fluid line,
characterised in that the step of providing an indication of an occlusion includes:
determining a slope relationship between the first and second force values by dividing a difference between the second force value and the first force value by a difference between time T2 and time T1; and
determining if the slope relationship departs from an expected slope relationship by comparing the slope relationship to the expected slope relationship, wherein an indication of an occlusion is provided if the slope relationship between the first and second force values departs from the expected relationship."

"2. The method of automatically detecting an occlusion of claim 1, wherein the fluid source (13) is a syringe (13), and the medical pumping system (10) is a syringe pump (10) having a housing (14) adapted to support the syringe (13) containing a plunger (16) moveable inside the syringe (13) by pushing an end of a plunger (16) with a pusher (17) to expel fluid from an outlet of the syringe into the fluid line (22) connected to the outlet so as to carry fluid under pressure to a patient (24), the method further comprising:
mounting the syringe (13) onto the housing (14) with the plunger end extended;
coupling the pusher (17) to the end of the plunger (16); and
initiating the pumping sequence to cause the fluid to flow into the fluid line (22)."

Reasons for the Decision

4. Main request - method for treatment of the human body by therapy - Article 53(c) EPC

4.1 The Opposition Division and the respondents/opponents considered that the step "initiating the pumping sequence to cause the fluid to flow into the fluid line" of claim 2 was a therapeutic step because it changed the patient's status through the injection of medicine. Even claim 1 fell under the exception of Article 53(c) EPC, because it encompassed the surgical step of placing the infusion needle and the therapeutic step of pumping medicine into the patient during the execution of the claimed method. The method decided on in T 245/87 was different from the present one in that it did not mention the patient in its wording.

4.2 The parties cited T 245/87. The object of that decision was to determine whether a flow measuring method applicable to an insulin pump implanted in a patient according to EP-A-0141965 fell under the exclusion of Article 52(4) EPC 1973 (equivalent to Article 53(c) EPC). More precisely, the method described there was entitled "A method for measuring the flow of small quantities of liquid passing through a tubular element" and was intended for measuring the flow of small liquid quantities in tubing of small diameter and with small flow speeds (page 4, lines 9 to 20), in particular for application to implanted medicine delivery devices (page 1, lines 20 to 25), for which it was important to be able to detect any disturbances in the functioning, such as occlusion of the narrow tubing (page 1, lines 25 to 35). The invention described there consists in measuring an electrical resistance between two electrodes placed in the electrically conductive fluid flowing in the tubing, once without a small gas bubble in the tubing and once with a small gas bubble in the tubing, and then deducing a flow time from the difference between the measured electrical resistances. In that decision the board considered that such a flow measuring method was not a method of treatment of the human body by therapy, because there was no functional link between the method claimed and the dosing of the drug administered by means of the device.

The decision includes the following passages:

"3.2 (...)
The subject-matter of Claim 1 does not include any steps constituting a functional link between the timing of the variation in resistance and the pump conveying the liquid in the example. Thus, the steps described in Claim 1, even when the method is applied to an implanted device for controlled drug administration, only involve measuring the volume of the drug solution flowing into the body per unit of time and the flow itself is not affected. These steps may therefore be performed without any medical knowledge and they have no therapeutic effect whatsoever in themselves.
(...)
3.2.2 (...)The operating parameters measured according to the method claimed allow the doctor complete liberty to plan the operating timetable of the pump - and thus the drug intake required for treatment - with medical discretion.
(...)
3.2.3 A method therefore does not fall within the scope of the first sentence of Article 52(4) EPC if there is no functional link and hence no physical causality between its constituent steps carried out in relation to a therapy device and the therapeutic effect produced on the body by that device."

4.3 The Enlarged Board of Appeal endorsed the approach of T 245/87 and similar decisions in G 1/07. Although this decision deals more specifically with the question of what is a surgical step and when does a claimed method fall under the exception to patentability for methods for treatment of the human body by surgery, in point 4.3.2 the Enlarged Board of Appeal addressed the methods only concerning the operation of a device and stated the following:

"The approach adopted in that jurisprudence has not been put into question in these proceedings and the Enlarged Board also sees no reasons for doing so. Methods which are merely directed to the operating of a device without themselves providing any functional interaction with the effects produced by the device on the body are teachings in which the performance of a physical activity or action that constitutes a method step for treatment of a human or animal body by surgery or therapy is not required in order for the teaching of the claimed invention to be complete. Hence, even if in such a case the use of the device itself requires the application of a surgical step to the body or is for therapeutic treatment the same does not apply to the claimed method for operating the device. It appears therefore to be correct to say that such inventions are not methods for treatment of the human or animal body within the meaning of Article 53(c) EPC and that the distinction made in the jurisprudence of the technical boards properly delimits patentable methods of a merely technical nature from such inventions as fall within the exclusion under Article 53(c) EPC. Whether or not a claimed invention only concerns the operation of a device without any functional link to the effects of the device on the body, is not an issue of law but requires an evaluation of the overall technical circumstances of the case and is therefore a matter to be determined by the first instance and the technical boards of appeal in the individual cases under consideration."

4.4 In the Board's opinion in the present case the subject-matter of claims 1 and 2 falls within this definition of methods only concerning the operation of a device. Indeed, the method according to claim 1 not only is entitled "A method of automatically detecting an occlusion in a downstream fluid line of a medical pumping system", which as such already points towards an occlusion detecting method only, but also basically only includes determining two force values at two different times, determining a slope relationship between the first and second force values by dividing a difference between the second force value and the first force value by a difference between time T2 and time T1, and determining if the slope relationship departs from an expected slope relationship by comparing the slope relationship to the expected slope relationship, wherein an indication of an occlusion is provided if the slope relationship between the first and second force values departs from the expected relationship. In other words, it involves no more than determining two force values at two different times, deducing a relationship and making a comparison in order to be able to give an indication of a possible occlusion. The Board fails to see how such experimental determination and mathematical comparison of two values has a functional link with the medicine being injected into the patient for his therapy. The execution of the said claimed method has in itself no influence whatsoever on the quantity, frequency or speed of delivery of a given medicine present in the pumping system. The method appears to be a monitoring method which will indicate whether or not there is a risk of occlusion in the downstream fluid line, but it does not influence the ongoing process of delivering medicine to the patient, let alone give the medical doctor an indication of any measure to be taken in relation to the therapeutic treatment of the patient in case an occlusion is likely to be present.

4.5 Claim 2 adds a more precise definition of the different mechanical parts composing the pumping system used and some steps necessary in order for the pumping sequence, during which the force values will be determined, to exist, namely mounting the syringe onto the housing with the plunger end extended, coupling the pusher to the end of the plunger and initiating the pumping sequence to cause the fluid to flow into the fluid line.

4.6 The respondents/opponents and the Opposition Division considered that the step of initiating the pumping sequence had to be considered a therapeutic step as it would change the status of the patient.

The Board does not share this view. This step has to be read in the context of the claimed invention, in particular bearing in mind the specific steps of the method as defined in claim 1. The method according to claim 1 requires the force values to be determined during a pumping sequence or, in other words, while fluid is steadily flowing through the downstream fluid line. Hence, the initiation of the pumping sequence (so that a pumping sequence exists) is already a necessary step to be able to carry out the method of claim 1 during such a pumping sequence. The fact that the method per se of detecting an occlusion should actually be guaranteed to be carried out during a pumping sequence as required by claim 1 is further emphasised in claim 5 and the following claims, where it is indicated that the steady-state condition is determined. Hence, this step of claim 2, when read in context, does no more than guarantee that there is a pumping sequence during which the actual detection method of claim 1 can be carried out.

It is further emphasised that in the Board's opinion such a step of initiating the pumping sequence in claim 2 is no different to the statement in claim 1 that the method is carried out during a pumping sequence. Of course, during a pumping sequence the patient will receive the medicine and after initiation of the pumping sequence he will receive the medicine as well. However, the experimental and mathematical determination of a possible occlusion in the fluid line has no effect on this steady or initial pumping and does not give the medical doctor any clue as to what should be done in the then ongoing particular therapeutic treatment in the event that the possible presence of an occlusion is indicated, i.e. as to the therapy. The present Board considers that the statement by the board in T 245/87 under point 3.2.2 is applicable in the present case: "The Board regards such a method as solely a matter for the apparatus designer. The operating parameters measured according to the method claimed allow the doctor complete liberty to plan the operating timetable of the pump - and thus the drug intake required for treatment - with medical discretion."

4.7 The respondents/opponents considered that the wording of claim 1 in T 245/87 did not include the patient whereas the wording of present claim 1 did, which would be an additional indication that the method was for therapy.

The Board does not share this opinion. While mentioning the patient in the wording of a method claim might be an additional sign that the claim merits careful examination as to its possible falling under the exceptions to patentability pursuant to Article 53(c) EPC, such mentioning of the patient is in itself not the decisive issue. What is decisive for the assessment of the question whether or not a method has to be considered a method for treatment of the human body by therapy is whether there is a functional link or a direct influence of the method claimed in itself on a given therapy, such that the medical doctor's freedom of choice and of practice in this respect is hindered. As explained above, the Board considers that this is not the case for the present method claims in the same way as this was the case in T 245/87.

4.8 For the same reasons as above, the necessary puncturing of the patient to connect him to the pumping system is, in the present case, irrelevant for the question of whether or not the method falls under the exceptions to patentability pursuant to Article 53(c) EPC.

4.9 Hence, in the present case the Board considers that the claimed method only concerns the operation of a device, without any functional link to the effects of the device on the body, and so the method does not fall under the exception to patentability pursuant to Article 53(c) EPC concerning methods for treatment of the human body by therapy or by surgery.