T 2562/18 21-07-2020

Reasons for the Decision

1. The invention

The invention relates to a machine-readable storage medium embodying instructions relating to a blood treatment therapy.

Such a therapy could be a Continuous Renal-Replacement Therapy (CRRT), indicated for critically ill patients. CRRT is a kind of slow and continuous dialysis therapy, which is better tolerated than the traditional dialysis as it does not involve sudden changes in the blood which may cause cardiovascular instability. Continuous Veno-Venous Hemofiltration (CVVH), Continuous Arterio-Venous Hemofiltration (CAVH), Continuous Veno-Arterial Hemofiltration (CVAH), Continuous-VenoVenous-Hemo-DiaFiltration (CVVHD or CVVHDF) and Continuous-Arterio-VenousHemo-DiaFiltration (CAVHD or CAVHDF), mentioned in paragraphs [0003] and [0004] of the patent are all special kinds of CRRT.

The instructions defined in claim 1 of the main request may be carried out, according to the patent, by an extracorporeal blood treatment system as schematically depicted in Figures 3 and 4 reproduced below.

FORMULA/TABLE/GRAPHIC

FORMULA/TABLE/GRAPHIC

The instructions comprise instructions for pumping blood from a patient into an access line (access line 1, by means of blood pump 14), introducing an anticoagulant solution into the blood (at inlet port 32, by means of anticoagulant pump 24), filtering the blood (in artificial kidney 60), delivering the blood to a return line (return line 2, from artificial kidney 60) and then back to the patient, introducing a calcium solution including magnesium into the filtered blood traveling through the return line (at connection 46, by means of second post-dilution pump 16), introducing a substitution fluid into the blood using a first pump coupled to the access line (via pre-dilution line 31, by means of pre-dilution pump 23), and introducing the substitution fluid into the blood also using a second pump coupled to the return line (via post-dilution line 52, by means of first post-dilution pump 50).

The introduction of the substitution fluid and the calcium solution are intended to supplement the blood in order to compensate the loss of liquid and other constituents due to the filtration process and possibly to promote that process (substitution fluid introduced in the access line). Controlling the administration of all these fluids is important so as not to have those sudden changes in the patient's blood, which make traditional dialysis not suitable for critically ill patients.

Claim 1 of auxiliary request 2 additionally specifies, in particular, that the anticoagulant solution and the calcium solution are to be introduced by respective pumps, and defines instructions for, when one pump halts for any reason, stopping the pumping of the other pumps, wherein the stops of the blood pump and the anticoagulant pump are delayed after the other pumps have stopped.

According to the patent (paragraph [0055]) this is done to fill the return line with blood containing anticoagulant, to avoid the risk of clotting inside this line when the blood is not circulating.

2. Main request - sufficiency of disclosure

2.1 Claim 1 of the patent as granted is directed to a storage medium embodying instructions for performing certain method steps to be carried out by an electronically controlled blood treatment system.

2.2 What the claim requires is the suitability of such instructions for carrying out the respective method steps by means of a blood treatment system appropriately set up for this purpose. In other terms, there is no claim requirement that the instructions should enable the system to distinguish between possible fluids to be conveyed. Still, when the conveyance of a certain fluid is referred to, the instructions should enable the conveyance of this specific fluid in view of the technical purpose of the blood treatment system, i.e. the performance of a suitable treatment of a patient. For example, the instructions for introducing an anticoagulant solution into the pumped blood should enable the introduction of such a solution from a source, the source being present in the system, at a time and at a flow rate which make it effective in the treatment without putting at risk the patient's health. These time and flow rate are well known to the person skilled in the art from the common general knowledge.

2.3 As the proprietor submitted, the patent discloses the technical means of an electronically controlled blood treatment system adapted to carry out the method steps defined in claim 1 on the basis of appropriate software instructions. These are, in particular, the pumps of the system as depicted in Figures 3 and 4. The opponents' argument that for some instructions - i.e. for filtering the pumped blood, delivering it to a return line and returning it to the patient - this was not the case is not convincing. It can be accepted that the patent may not disclose a single physical entity, such as a dedicated pump, for carrying out each of the claimed instructions. Still, each instruction may be carried out by the blood treatment system as a whole, in certain cases by the cooperation of more than one element of the system. For example, the delivery of blood to a return line with a system as depicted in Figure 3 will depend on the flow rates of blood pump 14, pre-dilution pump 23 and filtration pump 8, which can be controlled by specific instructions.

2.4 Hence, the Board concludes that the person skilled in the art can readily formulate the instructions for the respective purposes as defined in claim 1 on the basis of the disclosure of the patent (in particular paragraphs [0058] to [0062]) and the common general knowledge.

2.5 For the same reasons, also the instructions defined in claim 9 can readily be formulated by the person skilled in the art.

2.6 As far as claim 7 is concerned, the opponents argued that the removal of air by the means of air traps 3 (Figure 4) worked without any control from a CPU. However, the patent additionally teaches that air can be removed with the aid of an air bubble detector (33) controlled by a monitoring system (paragraph [0052]). This amounts to a disclosure of a technical means adapted to carry out the method step defined in claim 7, on the basis of appropriate software instructions.

The opponents further argued that the patent did not disclose how to distinguish between air bubbles introduced with the substitution fluid and air bubbles of another origin. However, claim 7 simply defines instructions for detecting air bubbles introduced with the substitution fluid, without distinguishing the origin of the bubbles. Detecting all air bubbles (as taught in the patent) will inevitably detect the air bubbles introduced with the substitution fluid.

2.7 It follows that the ground for opposition of insufficient disclosure (Article 100(b) EPC) does not prejudice the maintenance of the patent on the basis of the main request.

3. Main request - novelty

The opponents argued on the basis of documents D2, D2a, D11 and D11a. D2 and D2a belong to the same patent family and have the same technical content. The same applies to D11 and D11a. For ease of reference the Board will only refer to D2a and D11 in the following.

3.1 D2a concerns a system that can be employed for performing hemofiltration in intensive therapy (paragraphs [0002] and [0010]). Such a system is schematically depicted in Figure 1 reproduced below.

FORMULA/TABLE/GRAPHIC

D2a discloses an access line (3a) with a blood pump (21), an anticoagulant syringe (35) for introducing an anticoagulant into the blood, a blood filter (2), a return line (3b), a pump (9) suitable for introducing a calcium solution into the blood (paragraphs [0149] to [0151]), a pump (19) for introducing substitution fluid from a supply of substitution fluid into the blood traveling through the access line (paragraphs [0046] and [0047]) and a further pump (13) for introducing substitution fluid from another supply of substitution fluid into the blood traveling through the return line (paragraph [0075]).

These elements are controlled by a processing unit (40, paragraph [0105]). It follows that the system of D2a must comprise a machine readable medium (RAM or ROM) comprising suitable instructions for the processing unit.

The proprietor argued that D2a did not disclose the administration of a calcium solution including magnesium. The Board agrees. D2a generally discloses the administration of an electrolyte solution containing "suitable substances (for instance calcium) for recovering the ion balance in the blood" when citrates are used as anticoagulants (paragraph [0149]).

However, claim 1 merely requires instructions suitable for introducing a generically defined "calcium solution including magnesium". In the absence of a more precise definition of the solution, for example the respective concentrations of calcium and magnesium, the Board concludes that instructions for introducing an electrolyte solution of the kind mentioned in D2a at times and at a flow rate which make the administration effective in the treatment without putting at risk the patient's health will also be suitable for administering, for the same purpose, an electrolyte solution according to the definition of claim 1. As a matter of fact, the description of the patent does not describe either how the claimed instruction could possibly differ from an instruction for introducing a calcium solution as known from D2a.

The proprietor also argued that D2a did not disclose two pumps for introducing substitution fluid which pumped from the same fluid supply.

However, this is irrelevant as far as the nature of the instructions suitable for introducing the substitution fluid are concerned. The time and the flow rate of the administration do not depend on where the fluid comes from, but are only related to the administration means, in particular pumps 19 and 13 of D2a.

The Board therefore concludes that D2a discloses all the features of claim 1 of the main request.

3.2 D11 concerns a system that can be employed for performing hemofiltration in the context of CRRT (paragraph [0035]). Such a system is schematically depicted in Figure 3 reproduced below.

FORMULA/TABLE/GRAPHIC

D11 discloses an access line (102) with a blood pump (112), an anticoagulant pump (120), a blood filter (140), a return line (104), a pump (32) suitable for introducing an electrolyte solution into the blood (paragraph [0058]), a substitution pump (114a) for introducing substitution fluid from a supply of substitution fluid into the blood traveling through the access line (paragraph [0056]), and a substitution pump (114b) for introducing substitution fluid from another supply of substitution fluid into the blood traveling through the return line (paragraphs [0055] and [0056]).

These elements are controlled by a processing unit (70, Figure 2). It follows that the system of D11 must comprise a machine readable medium (RAM or ROM) comprising suitable instructions for the processing unit.

Pump 32 is suitable for administering a calcium and magnesium solution into the blood: paragraph [0018] discloses that infusions of calcium and magnesium (specific electrolyte solutions) can be administered, and paragraph [0058], discloses that pump 32, coupled to supply 156, can be used to administer, inter alia, electrolyte solutions.

Contrary to the proprietor's view, for the same reasons as those given with respect to D2a, D11 also anticipates instructions suitable for introducing a generically defined calcium solution including magnesium into the filtered blood traveling through the return line as required by claim 1.

For the reasons explained in view of D2a the fact that D11 does not disclose two pumps introducing substitution fluid which pump from the same fluid supply does not represent a differentiating feature either.

It follows that the subject-matter of claim 1 of the main request also lacks novelty in view of D11.

3.3 As a consequence, the patent cannot be maintained on the basis of the main request for lack of novelty (Article 54(1) and (2) EPC).

4. Auxiliary request 1 - added subject-matter

Claim 1 of auxiliary request 1 is based mainly on claim 1 of the original application and claim 34 of the parent application as filed, in combination with page 17, lines 18 to 29, of the original application and paragraph [0055] of the parent application as filed as regards the feature "instructions for, when one pump halts for any reason, stopping the pumping of the other pumps, wherein the stops of blood pump (14) and anticoagulant pump (24) are delayed after the other pumps have stopped".

4.1 The definition of the machine-readable medium being a "storage medium" is based on paragraph [0067] of the parent application and page 21, lines 4 to 16 of the original application as filed. These passages expressly refer to "the methods or algorithms described in connection with the embodiments disclosed herein". Hence they constitute a general disclosure for all the embodiments of the invention. It follows that the opponents' argument regarding an alleged intermediate generalisation in this respect is without merit.

4.2 A basis for the definition that the substitution fluid introduced before and after the blood filter is the same fluid is provided by claims 2 and 3 of the original application and claims 35 and 36 of the parent application as filed, and by Figure 3 of the parent and the original application as filed. The Board does not accept the opponents' argument that it should be specified that this substitution fluid does not contain calcium and magnesium ions. Those claims of the original application and the parent application as filed did not specify it either. The presence or absence of calcium and magnesium ions in the substitution fluids is in no technical relation to issue of whether one or more of such fluids is used.

4.3 The opponents' argument concerning the absence of the definition that the instructions are for carrying out hemofiltration is not convincing for similar reasons. Claim 1 of the original application and claim 34 of the parent application as filed did not require it either. The use of a single substitution fluid or the specific instructions concerning the stopping of the pumps cannot make this definition necessary, from a technical point of view.

4.4 The additional features of claim 9 are based on paragraph [0054] of the parent application and page 17, lines 15 to 17 of the original application as filed. Contrary to the opponents' submissions, these passages are not specific to dialysis devices, but concern the nature of the substitution fluids, and the pumps and tubing employed in any of the disclosed blood treatment systems. There is thus no inextricable link between the specific nature of the fluids mentioned in these passages and the means for their administration. Hence, the opponents' objection of added subject-matter directed to claim 9 is not convincing.

4.5 However, the introduction of the feature "instructions for, when one pump halts for any reason, stopping the pumping of the other pumps, wherein the stops of blood pump (14) and anticoagulant pump (24) are delayed after the other pumps have stopped" in claim 1 of auxiliary request 1 is problematic.

The opponents argued that it constituted an unallowable intermediate generalisation, in particular because claim 1 did not specify that all pumps were controlled together, that when the blood pump run all other pumps had to be activated, and that the administration of the solution containing calcium and magnesium had to stop before the stop of the blood pump and the anticoagulant pump.

As regards the allegedly omitted feature that all pumps are controlled together, this is implied by the claim on a technical reading of it. The claimed instructions, when implemented, result in the stop of all the pumps. This implies their control.

Claim 1 of the original application and claim 34 of the parent application as filed did not prescribe that when the blood pump runs all other pumps have to be activated. Moreover, this feature is clearly not inextricably linked with the claimed delay of the stop of the anticoagulant pump and the blood pump, which is for preventing clogging of the return line when the system stops (paragraph [0055] of the parent application and page 17, lines 18 to 29 of the original application as filed). It follows that its omission does not add subject-matter.

However, as the opponents argued, the omission of the feature that the administration of the solution containing calcium and magnesium should stop before the stop of the blood pump and the anticoagulant pump is not allowable. If that administration is not stopped the prevention of the risk of clogging the return line, which is what the claimed instructions aim at, is not achieved: free calcium ions, which play an important role in the coagulation of blood and which are bound by the anticoagulant, would be re-introduced into the blood. Hence, the original application and the parent application as filed inextricably link the omitted feature with the claimed instructions of stopping the pumps. In contrast, claim 1 of auxiliary request 1 conveys the information that the stopping of the administration of the solution containing calcium and magnesium is merely optional.

The proprietor's argument that claim 1 of auxiliary request 1 had to be understood to imply that the administration of the solution containing calcium and magnesium should stop before the stop of the blood pump and the anticoagulant pump is not convincing. The claim does simply not state that such administration is performed by means of a pump. Moreover, a pump is not the only possible technical means for performing that administration. The solution could be delivered from an infusion bag by gravity or from a reservoir under pressure, whereby the flow rate could be controlled by a regulating valve, for example. Hence, stopping the pumps does not necessarily result in stopping the administration of the solution containing calcium and magnesium.

4.6 For this reason the subject-matter of claim 1 of auxiliary request 1 extends beyond the content of the original application and the parent application as filed, in contravention of Articles 76(1) and 123(2) EPC.

Hence

5. Auxiliary request 2 - Article 123(2), 83 and 84 EPC

In claim 1 of auxiliary request 2 it is expressly mentioned that the calcium solution including magnesium is administered by a pump, i.e. the second post-dilution pump. Hence, the claimed instructions for stopping all the pumps of the system imply that the administration of this solution stops before the stop of the blood pump and the anticoagulant pump. This overcomes the non-compliance with Articles 76(1) and 123(2) EPC explained above.

For the reasons given in the analysis of the main request made above, auxiliary request 2 also meets the requirements of sufficiency of disclosure.

6. Auxiliary request 2 - Novelty and inventive step

It is common ground that D2/D2a and D11/D11a do not disclose instructions for, when one pump halts for any reason, stopping the pumping of the other pumps, wherein the stops of blood pump and anticoagulant pump are delayed after the other pumps have stopped.

6.1 The opponents argued that since this distinguishing feature concerned a technical problem which was different from the problem addressed by the other claim features a combination of more documents could prejudice the novelty of the claim.

It is the established jurisprudence that, in the assessment of novelty, the claimed invention should be compared with the prior art to see whether the invention differs from it. If it does, no matter for which reason, the invention is novel. In the comparison it is not permissible to combine separate items of prior art together. A claimed subject-matter would lack novelty only if a "clear and unmistakable teaching" of a combination of the claimed features could be found in a prior art disclosure (Case Law of the Boards of Appeal of the European Patent Office, Ninth Edition, July 2019, I.C.4.2 and I.C.5.1).

It follows that the opponents' objection of lack of novelty based on the combination of separate documents (D2/D2a or D11/D11a with D10) is without merit.

6.2 The opponents argued against inventive step starting from D2/D2a or D11/D11a, in combination with one or more of D10, D31 and D32.

D2/D2a and D11/D11a do not disclose instructions for, when one pump halts for any reason, stopping the pumping of the other pumps, wherein the stops of blood pump and anticoagulant pump are delayed after the other pumps have stopped.

As the proprietor submitted, the patent (paragraph [0055]) explains that this distinguishing feature allows to fill the return line with blood containing anticoagulant, to avoid the risk of clotting inside this line when the blood is not circulating.

This solves the objective technical problem of increasing the safety of a patient under treatment, in case the treatment is continued after the stop of all pumps.

6.2.1 D10 (column 17, lines 25 to 30) discloses a "safe state" of an extracorporeal blood treatment apparatus in which all pumps of the apparatus are stopped. Column 19, lines 52 to 57, discloses that a control processor puts the apparatus in the "safe state" if a pump is malfunctioning. According to column 19, lines 57 to 64, if the malfunction is detected "the operator may choose [...] to disconnect the patient with or without returning treated blood to the patient". The opponents argued that this implied that the blood pump had to run longer than the other pumps before being eventually stopped so as to reach the "safe state". Even if this were accepted, there is no disclosure in D10, either explicit or implicit, that the anticoagulant pump should continue running together with the blood pump. The Board notes that D10 is silent about any risk of blood clotting for the purpose of returning the treated blood to the patient before disconnection. This risk is not implicit either, since during that operation the blood would circulate normally in the blood treatment apparatus. It follows that D10 does not disclose the distinguishing feature. It is not concerned with the objective technical problem either.

6.2.2 D31 concerns a system for performing hemodialysis employing citrate as an anticoagulant (column 3, lines 5 to 12). In column 4, lines 57 to 68, D31 teaches that the system should be monitored to ensure that citrate and calcium ions are being added during the hemodialysis operation and that the blood pump should be monitored with the dialyser for determining if and when the blood is bypassing the dialyser. Column 5, lines 30 to 42, mentioned by the opponents, concerns this last situation. It discloses:

"the calcium ion pump should be shut down immediately whereas the blood pump should be shut down only after a delay of, e.g., 3 minutes. This permits sufficient time to adjust the dialyzer apparatus without shutting the entire apparatus [...] down. This for the reason that bypass operations are relatively common, and a patient would be in no danger for a short period while attempts are made to put the dialyzer apparatus back on stream. In addition, the citrate pump should be shut down after a period of time following shut down of the blood pump, e.g., 4 minutes after monitoring of a bypass condition in the dialyzer".

Hence, D31 does not disclose instructions for, when one pump halts for any reason, stopping the pumping of the other pumps. In fact, it suggests that the bypass condition is relatively common and should be solved without the need of a complete stop of the system. Moreover, D31 does not teach to fill the return line with blood containing anticoagulant in order to solve the objective technical problem, but simply to purge it altogether by leaving the anticoagulant pump in operation after the blood pump has stopped. It follows that D31 does also not suggest that the objective technical problem should be addressed as it is done by the claimed invention.

6.2.3 D32 concerns a system for CRRT, in particular hemofiltration, comprising, inter alia, a blood pump and an anticoagulant pump (page 9). On page 29, referred to by the opponents, it is explained that pressing a button "Behandlung Start/Stop" activates a function of the system in which a pre-dilution pump, a post-dilution pump and a filtrate pump are stopped while the blood pump continues working. On page 30, also referred to by the opponents, it is disclosed that a syringe containing an anticoagulant can be replaced activating a further function of the system. This implies an interruption of the administration of the anticoagulant. However, there is no disclosure in D32 that these functions are in any relation to each other. In particular, there is simply no disclosure in D32 that the anticoagulant delivery can only be interrupted by activating the function of the syringe replacement or that when the function "Behandlung Start/Stop" is activated the anticoagulant syringe continues delivering anticoagulant. Hence, D32 does not disclose the distinguishing feature of claim 1 of auxiliary request 2. It does not address the objective technical problem either.

6.2.4 Since none of D10, D31 and D32 teaches the distinguishing feature for the solution of the objective technical problem, their combination with D2/D2a or D11/D11a does not render obvious the subject-matter of claim 1.

6.3 The opponents also argued against inventive step of claim 1 of auxiliary request 2 starting from D32, under the assumption that this document disclosed all the claim features except the administration of a calcium solution containing magnesium by the means of a pump, and that this feature was rendered obvious by several other documents of the state of the art.

However, as explained above, D32 does not disclose the claimed instructions for stopping the pumps either.

It follows that the objection starting from D32 is without merit for this reason alone.

6.4 In conclusion, the subject-matter of claim 1 of auxiliary request 2 - and a fortiori of dependent claims 2 to 9 - is novel (Article 54(1) and (2) EPC) and inventive (Article 56 EPC).