T 0245/87 (Flow measurement) of 25.9.1987

Summary of Facts and Submissions

I. European patent application No. 84 110 884.8 filed on 12 September 1984 and published as No. 0 141 965 was refused by the Examining Division on 22 April 1987.

II. The reasons given for the refusal were based on Article 52(4) EPC. ...

III. The applicants ... appealed against this decision ... Method Claims 1-4 according to the main request read as follows: "1. A method for measuring the flow of small quantities of liquid passing through a tubular element (5) into which a gas bubble (1) is injected and the time taken by the bubble to traverse the distance between two fixed points (M1, M2) spaced longitudinally apart within the tubular element (5) is measured, the diameter of the bubble (1) being essentially the same as the internal diameter of the tubular element (5), and the rate of flow thus ascertained being used to determine the volume of liquid passing through said element, characterised in that in order to measure the rate of flow of an electrically conductive liquid the electrical resistance of the said liquid is measured between the two points (M1, M2) in the longitudinal direction of the tubular element (5), the resistance between said two points being relatively low when there is no bubble (1) and relatively high when there is a bubble between them, and in that the variations in resistance are used to determine the rate of flow. ...

4. Method as described in one of Claims 1 to 3, characterised in that a control signal (s), derived from the flow time, is provided in order to control a device (15) for conveying the liquid (7)." ...

Reasons for the Decision

3. Under Claim 1 as it stands patent protection is sought inter alia for a method (with the claimed features) in which the electrically conductive liquid, according to the example given in the description, contains a drug such as insulin (page 9, line 7) and is introduced into the body through the pump of an implantable device for controlled drug administration (page 7, lines 15-20). This first raises the question as to whether the method claimed in this specific application is to be regarded as a method for treating the human or animal body by therapy within the meaning of the first sentence of Article 52(4) EPC. In the Board's opinion the introduction of a drug into the human body by means of a device for controlled drug administration that has already been implanted is clearly unconnected with either a surgical or a diagnostic method.

3.1 The Board sees the problem inferable from the application documents with regard to Claim 1 as the development of a reliable system, based on the detection of very small volumes of flowing liquid, for checking the operation of devices for controlled drug administration in a miniaturised form particularly suitable for implanted devices; cf. also page 1, line 20 to page 2, line 18 and page 4, lines 15-20 of the description. The miniaturisation of a system for monitoring a device to ensure that it is in working order has to do exclusively with the production of an effect on the structure of the device and is not itself influenced by the effects produced by the device on the body. The check on the operation of the device therefore requires no medical knowledge whatsoever as regards the behaviour of the body into which the device is introduced. For this reason the Board is satisfied that the problem objectively inferable from the application documents is addressed solely to the engineer designing the device for controlled drug administration and not to the doctor using the finished product.

3.2 The above problem is solved according to Claim 1 by measuring the time during which a gas bubble (1) carried by the flow of liquid (7) along a tube (5) increases the electrical resistance between two separate measuring points (M1, M2) spaced longitudinally apart within the tube. 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. The solution to the problem solely involves obtaining, by the exertion of natural forces, information on the current working order of the device, and the body in which the device is implanted is not affected. The problem of miniaturising a system for checking that a device is operational is therefore clearly solved by purely technical means.

3.2.1 On account of the lack of operative connection in Claim 1 between timing and the pump, the Board cannot share the Examining Division's opinion in the last two lines of page 3 of the impugned decision that the steps of the method indicated in Claim 1 would themselves, if carried out in an implanted device for controlled drug administration, enable a set dose to be administered and monitored. The fact that, while the flow is being timed in accordance with Claim 1 in an implanted device, a drug is also passing into the body generally with a therapeutic effect, is not sufficient on its own in the Board's view to justify a finding that the flow timing is therapeutic. On the contrary, for this to be so, the result of the method would have to influence the quality or quantity of the drug flow. This is, however, not the case here: the result of the method is merely a reading indicating in terms of quantity the time required for a volume of fluid such as insulin solution, predetermined by apparatus setting, to flow between the measuring points (M1, M2). It merely characterises a property of the device, i.e. the capacity of the pump (15) under the selected operational parameters, and does not affect the actual quantity of insulin conveyed. The steps described in Claim 1, even in an implanted device for controlled drug administration, therefore represent no more than a method of measuring the efficiency of the pump fitted in the device.

3.2.2 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. Hence, even if under Claim 1 protection is granted for a method of measurement carried out in relation to an implanted device for controlled drug administration, the doctor is in no way hindered in exercising his professional skills, i.e. preventing, curing or alleviating illness; cf. also the definition of therapeutic action in point 3 of Decision T 144/83 of EPO Technical Board of Appeal 3.3.1 dated 27 March 1986 (OJ EPO 1986, 301, 304). Non- commercial and non-industrial medical and veterinary activities are therefore not restricted by patent rights in this case; cf. in this connection point 22 of Decision G 1/83* of the EPO Enlarged Board of Appeal dated 5 December 1984 (OJ EPO 1985, 60 - 63). * For the corresponding english version see G 5/83, OJ EPO 1985, 64 - 66 "Second Medical Indication/EISAI Co. Ltd.".

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.

3.3 For the reasons stated above, the Board is satisfied that the steps claimed in Claim 1 are exclusively technical and therefore industrially applicable, even if carried out in an implanted device for controlled drug administration as in the example given in the description. In these circumstances it is no longer necessary to decide whether a claim defining both subject-matter which is susceptible of industrial application and subject-matter which is not must be explicitly limited to the former subject- matter in order to fulfil the requirements of the EPC.

4. ...

5. The method described in Claim 4 covers the functional link between flow-rate measurement and the feed pump, lacking in Claims 1-3, which could enable fluid dosage to be regulated. The question whether the execution of the steps set out in Claim 4 in relation to an implanted device for controlled drug administration constitute steps of a therapeutic method within the meaning of the first sentence of Article 52(4) EPC therefore needs to be considered separately.

5.1 The subject-matter of Claim 4 is limited to the general teaching that a control signal for a liquid-feed device, such as a pump, may be derived from the measured rate of flow. The description gives no further explanation as to how the control signal is obtained or what effect it has on, say, a pump. Consequently the claim - either on its own or in conjunction with the description - does not even furnish the maker of the device with the technical details of how a discretionary fluid dosage can be introduced into the body.

5.2 In the Board's opinion, a finding that a claim seeks protection inter alia for a therapeutic method covered by Article 52(4) EPC is not warranted unless the said claim defines a control mechanism in full technical detail which, when embodied in an implanted device for controlled drug administration, clearly determines when what volume of which drug fluid is fed to the body within what period of time. Only then would the controlling action claimed, when featured in an implanted device for controlled drug administration, have any functional connection with the quality and quantity of the drug dose and a direct causal influence on the therapeutic effect produced, thus hindering the doctor in the exercise of his professional skill. The derivation and use of the control signal as specified in Claim 4, however, merely enhances the technical capabilities of the device and does not cause any such hindrance.

5.3 The subject-matter of Claim 4 therefore likewise does not require a decision on the admissibility of claims with a field of application which is partly non-industrial.

5.4 A method of measuring the flow of small quantities of liquid is therefore not automatically excluded from patentability by Article 52(4) EPC, even if used in an implanted device for controlled drug administration, as long as there is no functional link between the method claimed and the dosing of the drug administered by means of the device.

6. For the reasons stated above, the Board is satisfied that the subject-matter of Claims 1 to 4 meets the requirements of Article 52(4) EPC without limitation, either verbal or substantive or both, and without a disclaimer in Claim 1. ...

ORDER

For these reasons, it is decided that:

1. The contested decision is set aside.

2. The case is remitted to the Examining Division for resumption of the examination proceedings on the basis of Claims 1 to 14 filed on 6 July 1987.