T 1925/08 (Infrared dye/SIEMENS) 01-07-2013

Reasons for the Decision

Main request (claims as granted) - Article 100(c) EPC

1. In the decision under appeal, the opposition division found that Article 100(c) EPC prejudiced the maintenance of the patent as granted. In particular, the opposition division held that the subject-matter of claim 1 extended beyond the content of the application as filed because the negative feature "... said infrared dye not labelling a component of said reagent composition", which had been introduced into claim 1 in examination proceedings to establish novelty over intermediate document (5) (cited as D6 in examination proceedings), was neither disclosed in the application as filed nor met the requirements established by the Enlarged Board of Appeal in decisions G 1/03 and G 2/03 (OJ EPO 2004, 413 and 448) for a disclaimer to be considered allowable.

2. In appeal proceedings, appellant I maintained that the objected feature had a basis in the application as filed, in particular on the passages on page 12, lines 3 to 8 and page 9, lines 11 to 14. These passages read:

"In embodiments wherein the IR dye is incorporated into a test pad, the IR dye cannot adversely affect the reagent incorporated into the test pad or adversely affect an interaction between the analyte of interest and reagent present in the test pad" (page 12, lines 3 to 8)

"In another aspect of the invention, the IR dye is incorporated into a test pad of the strip, either in conjunction with the assay reagent or separately from the assay reagent" (page 9, lines 11 to 14)

3. Like the opposition division, the board is not convinced that a person skilled in the art could derive, directly and unambiguously, from the passages of the application as filed quoted above that the infrared dye on the claimed test strip does not label a component of the reagent composition. As regards the first passage, the statement that neither the reagent incorporated into the test pad nor the interaction between the reagent and the analyte of interest should be adversely affected by the infrared dye would not be interpreted by a person skilled in the art as a requirement that the infrared dye does not label a component of the reagent composition. Labelling a component of the reagent composition with an infrared dye does not necessarily have to interfere or adversely affect the reagent incorporated into the test pad or its interaction with the analyte. Conversely, if there is an adverse effect in the presence of an infrared dye, it may be caused by different kinds of interaction between the dye and a component of the reagent, other than labelling.

4. As regards the second passage, the board does not share appellant I's view that the skilled person could derive the objected feature from the statement that the infrared dye can be incorporated into the test pad separately from the assay reagent. Two different embodiments are disclosed in this passage. While the possibility that the infrared dye labels a component of the reagent composition would in fact be logically excluded in the second embodiment, it cannot be excluded from the first (i.e. the infrared dye is incorporated in conjunction with the assay reagent). Thus, the feature that the infrared dye does not label a component of the reagent composition cannot be considered to be unambiguously derivable from this passage.

5. In appeal proceedings, appellant I did not contest the opposition division's finding that the negative feature in claim 1 cannot be regarded as an allowable disclaimer (see G 1/03 and G 2/03, supra), and the board does not see any reasons which may allow a different finding.

6. In view of the above, the board confirms the opposition division's finding that Article 100(c) EPC prejudices the maintenance of the patent in the granted form.

Admission of the claims according to the first and second auxiliary request into the proceedings

7. Claims 1 to 14 of the first auxiliary request presently on file were filed on 2 July 2009 and are essentially identical to those of the first auxiliary request submitted together with the statement of grounds of appeal, except for an amendment of the wording introduced by appellant I to remedy a clarity deficiency. The set of claims according to the second auxiliary request was filed together with the statement of grounds of appeal.

8. Both requests have been filed in an attempt to overcome the ground for opposition raised under Article 100(c) EPC, which was considered by the opposition division to prejudice the maintenance of the patent in the granted form.

9. However, in the summons issued in preparation of the oral proceedings the opposition division had expressed the (provisional) view that there was a basis in the application as filed for the contested negative feature, and that the feature in question also fulfilled the requirements for an allowable disclaimer established in decision G 1/03 (supra). Appellant I has credibly argued that it had been taken by surprise by the opposition division changing its mind during the oral proceedings, and that, under time pressure, it had not been able to amend the claims to obviate the objected negative feature and avoid the "inescapable trap" of Article 123(2) and (3) EPC.

10. In view of these particular circumstances, the sets of claims according to the first and second auxiliary request are admitted into the proceedings.

First auxiliary request (claims 1 to 14 filed on 2 July 2009) - Article 123(3) EPC

11. The board accepts that amended claim 1 was filed as an attempt to overcome the objection under Article 100(c) EPC by replacing the negative feature lacking a basis in the application as file by the feature that the infrared dye is positioned on the support handle of the test strip (see decision G 1/93; OJ EPO 1994, 541). The question arises whether or not the amendment breaches Article 123(3) EPC.

12. In appellant I's view, the feature introduced into claim 1 limited the claimed subject-matter to test strips in which the infrared dye was positioned outside of the test pad. Since according to the claim the reagent composition was located only in a test pad, this necessarily implied that the infrared dye would not label a component of the reagent composition, as required in claim 1 as granted.

13. The board disagrees with appellant I's interpretation of the introduced feature. Although the wording "support handle" appears to be somehow ambiguous, it is apparent from claim 1 itself and, especially, from claim 3, which is dependent on claim 1 and specifies that "... the infrared dye is incorporated into one or more test pad", that the feature "said infrared dye being positioned on the support handle" does not preclude the infrared dye being incorporated into a test pad where the reagent composition is also located. Thus, as appellant II argued, the new feature does not introduce any limitation to the scope of the claim. Since, on the other hand, the limiting negative feature included in claim 1 as granted has been omitted in the amended claim 1, the latter claim encompasses subject-matter which extends beyond the scope of the claims as granted, contrary to Article 123(3) EPC.

14. For the sake of completeness, the board observes that, even though the additional feature "... wherein the handle is formed from hydrophobic material" in amended claim 1 is, in fact, a limiting feature, the scope of the claim has, nevertheless, been extended compared to claim 1 as granted, as a result of the omission of the negative feature. Since the additional feature does not limit the scope of the claim to the same - or a larger - extent that it is extended by the omission of the negative feature, the amendments introduced into the claim do not conform to Article 123(3) EPC.

15. It follows from the above that, contrary to appellant I's request, maintenance of the patent in amended form cannot be based on the claims according to the first auxiliary request.

Second auxiliary request (claims 1 to 14 filed together with the statement of grounds of appeal) - Article 123(3) EPC

16. A similar conclusion is reached in respect of the amended claim 1 of the second auxiliary request. Claim 1 of this request specifies that the infrared dye is incorporated into one or more test pad, the dye not adversely affecting the reagent incorporated into the test pad. As stated above in connection with the main request (see point 3 above), an infrared dye that labels a component of the reagent composition could, but not necessarily has to adversely affect the reagent composition. Since the feature "not adversely affecting the reagent" excludes from the scope of the claim only those embodiments in which there is in fact an adverse effect, the amended claim seems to encompass those embodiments of the test strip in which a component of the reagent is labelled with an infrared dye, but the labelling has no deleterious effects on the reagent or the interaction with the analyte. Such an embodiment of the test strip did not fall under the scope of the claims as granted.

17. Since as a consequence of the amendment the scope of the claim has been extended, contrary to Article 123(3) EPC, the patent cannot be maintained on the basis of the claims of the second auxiliary request.

Third auxiliary request

Articles 123(2) (3), 84 and 83 EPC

18. No objections under these articles were raised by appellant II, and the board does not see any reason to do it of its own motion. Thus, the respective requirements are regarded as fulfilled.

Article 54 EPC - Novelty

19. In the decision under appeal, the opposition division decided on objections of lack of novelty raised by the opponent relying on documents (1) and (2). In its statement setting out the grounds of appeal, appellant II submitted arguments against the novelty of the subject-matter of present claim 1 with regard to documents (2) and (6), and in its further written submissions documents (6) and (9) were also cited . However, at the oral proceedings appellant II stated that its novelty objection was based solely on documents (1), (2) and (4).

Document (1)

20. In the decision under appeal, the opposition division found that the claimed methods of monitoring alignment of a test strip in an optical pathway of a detection apparatus were novel with regard to document (1). In the opposition division's view, the purpose of the method described in document (1) was to enable a quantitative correction of the measurement carried out on a "primary color forming or color changing indicator" in a reagent composition. This was achieved by using a secondary inert chromogen marker, e.g. an infrared dye. The opposition division stated that "correction" in document (1) was meant to be a numerical calculation, rather than monitoring the position of the test strip in a detection apparatus, as in the claimed method. Consequently, the step of correlating the reflectance measurement of the infrared dye to the alignment of the test strip in the detection apparatus (step (e) of the method of claim 1) could not be derived from document (1) (see section 5.6 of the decision under appeal).

21. Appellant II contested this finding relying in particular on the passage in column 12, lines 46 to 56 of document (1). This passage reads:

"The secondary, inert chromogen marker is capable of correlating primary chromogen reflectance measurement to achieve approximately a two-fold increase in measurement accuracy. The secondary, inert chromogen marker corrects for variations in reagent pad scattering coefficient, pad thickness, pad volume, reflectance of reagent strip backing or support material, height variability of the reagent pad, position variability of the reagent pad and drift within the specrophotometer[sic]"

22. The board observes that, rather than appellant's line of argument, this passage supports the opposition division's view that the purpose of a "correction" in the method of document (1) is not to monitor the alignment of the test strip in the detection apparatus, but to achieve an increase in measurement accuracy by introducing into the calculation a "correction factor" which is derived from the measurement of a secondary, inert marker. The board also remarks that the whole second sentence in this passage, and specifically the wording "position variability of the reagent pad", on which appellant II particularly relied, relates to the correction of variations concerning the reagent pad. Thus, the wording "position variability" in the passage quoted above is understood by the board as referring to the variability in the position of the reagent pad within the test strip, rather than to a possible misalignment of the test strip within the detection apparatus.

23. This interpretation is supported by the passage on column 5, lines 33 to 37, to which the opposition division referred in its decision, and which reads:

"This correction factor allows the calculated concentration of the analyte to be corrected for variations in reagent strip characteristics such as thickness and scattering coefficient as well as instrumental variability" (emphasis added by the board)

In the board's understanding, the wording "instrumental variability" in this passage stands for a variation between different detection apparatuses, rather than for a variation in the position of the test strip within the detection apparatus.

24. For these reasons, the board concludes that document (1) does not describe a method of monitoring alignment of a test strip in an optical pathway of a detection apparatus comprising the step of correlating the reflectance measurement to the alignment of the test strip. Hence, document (1) is not prejudicial to the novelty of claim 1.

Document (2)

25. In the decision under appeal, the opposition division held that document (2) did not destroy the novelty of claim 1 because this document did not describe measuring the reflectance of infrared radiation from an infrared dye for monitoring the alignment of a test strip in a detection apparatus (see sections 5.2 to 5.4 of the decision under appeal).

26. It is undisputed that document (2) describes a method using a test strip with a marker field absorbing in the infrared region. Also steps b) to d) of the method of present claim 1 can be derived from this document (see, e.g., claim 1 in document (2)). Thus, for the assessment of novelty with regard to document (2), the decisive question is whether or not this document describes a method of monitoring the alignment of the test strip in a detection apparatus.

27. In this respect, appellant II pointed to the passage on column 8, lines 13 to 18 reading:

"[The color coding sequence] ... can also allow the software to look up information on critical measurement parameters such as location of reacting areas, critical times, strip age, and reactivity. After the color sequence has been identified, the instrument will move the test strip to the proper location, i.e. test field 501 ..."

The passage goes on as follows:

"... and collect data at the proper wavelengths and at the proper time or times such that the collected data can be analyzed by an appropriate algorithm to complete the assay" (see column 8, lines 19 to 22)

28. As indicated by the opposition division in the decision under appeal, it is apparent from the quoted passage that, after the test strip is moved to the proper location based on the information provided by the "color coding sequence" (e.g. a bar code with marker fields absorbing in the infrared regions of the spectrum), the test results for the analyte are measured. Hence, the purpose of the "color coding sequence" described in document (2) is not to assess whether or not the strip has been correctly introduced into the apparatus, but to direct the test strip to a position in which the analyte can be measured.

29. For these reasons, the board shares the opposition division's view that, with regard to document (2), the method of claim 1 is novel.

Document (4)

30. During the oral proceedings, appellant II raised - for the first time in appeal proceedings - a novelty objection in respect of the claims of the third auxiliary request relying on document (4). According to Article 13(1) RPBA, any amendment to a party's case after it has filed its grounds of appeal or reply may be admitted and considered at the board's discretion. This discretion is exercised taking into account, inter alia, the state of the proceedings.

31. There is no doubt that appellant II could have raised and substantiated a novelty objection against claims 1 to 5 of the third auxiliary request based on document (4) much earlier in appeal, for instance in the statement of grounds of appeal, the reply to appellant I's statement or any of the numerous submissions filed in appeal (see sections X, XII, XIV and XVIII above). Appellant II did not give any reason why the objection was submitted at such a late stage of the proceedings. Since the late submission deprived the other party of the time required for a careful preparation of counter-arguments, the board, exercising its discretion under Article 13 RPBA, decides to disregard the novelty objection based on document (4). The objection is, thus, not subject of this decision.

32. Summarising the above, the board concludes that the subject-matter of claim 1 - as well as that of dependent claims 2 to 5 - is novel with regard to documents (1) and (2).

Article 56 EPC - Inventive step

33. In the decision under appeal, document (1) was regarded as the closest state of the art, and the objective technical problem to be solved as the provision of an alternative method of avoiding errors due to position variability. The opposition division took the view that the subject-matter of the claims was not obvious in view of the content of document (1) alone or in combination with either document (6) or document (4) (see sections 6.3 and 6.4 of the decision under appeal).

34. In its submissions in appeal proceedings, appellant II relied on document (6) as the closest state of the art, and argued that the subject-matter of the present claims lacked an inventive step in view of the combination of this document with any of documents (1), (2) and (4).

35. Document (6) describes a device for photometric analysis of liquid samples, in particular body fluids. The device has two reading units for reading test strips having a test field onto which the liquid sample has been applied. The test strip is provided with two coding systems: the first coding system is a bar code consisting of bars of varying width, and the second coding system has a bar code including a clock track and a data track. When the test strip is inserted into the device, the clock track is read by one reading unit, which triggers the reading of the data track by the other reading unit (see claim 1 in document (6)).

36. In order to ensure that the test strip has reached and also maintains a predetermined position within the device, the test strip can be provided with an additional mark. If the test strip has been correctly introduced, this mark is positioned in front of the reading units. By reading the mark, the device monitors whether or not the test strip has reached the final position for measurement ("Endlagenkontrolle"; see paragraph bridging columns 1 and 2).

37. Figure 5 of document (6) shows a test strip 34 having a data track 72 which includes information required for measuring the test results, and a track 74 for monitoring the correct position ("Endlagenanzeige"). The track can be provided as a bar code or a single bar on the test strip (see column 5, lines 11 to 14).

38. Contrary to the opposition division's assessment, the board takes the view that a person skilled in the art can derive from document (6) a method having the same purpose as the method of the present invention, namely to monitor whether or not a test strip is correctly aligned in the optical pathway of a detection apparatus. The difference between the two methods is that, instead of a bar code or a single bar in black colour as used in document (6), the method of the present invention uses an infrared dye. Accordingly, in the claimed method, the predetermined location where the infrared dye is located on the test strip has to be illuminated with infrared radiation (step (c) in claim 1), and a reflectance of infrared radiation from the predetermined location measured (step (d) in claim 1). Also these features of the claimed method cannot be derived unambiguously from document (6).

39. Appellant II argued that the term "infrared dye" as defined in the patent (see paragraph [0033] of the patent specification) included any dye that absorbs not only in the infrared region, but also at different wavelengths. Thus, in its view, a black ink which shows at least some absorbance in the infrared region has to be regarded as an "infrared dye".

40. The board disagrees with this view. Paragraph [0033] of the patent specification defines an infrared dye as a dye having a strong absorbance in the infrared region. Apart from the fact that there appears to be no evidence on file showing that the black ink used in document (6) has a strong absorbance in the infrared region, the board observes that, even if the black ink may possibly absorb infrared radiation to a certain extent, a person skilled in the art reading document (6) would not learn from the document that absorbance in the infrared region is an essential feature of the ink. When determining the content of document (6) for the assessment of inventive step, the question to be decided is what this document makes available to a skilled person, not what might be inherent in what is made available (see decision G 2/88, OJ EPO 1990, 93).

41. Both the method of document (6) and the method of the invention seem to achieve the same technical effect: an increased accuracy and the avoidance of false negative assay results. In the absence of any hint in document (6) to possible drawbacks or any suggestion for improvements, in particular in respect of the track for monitoring the correct position, the problem to be solved must be formulated as the provision of an alternative method of monitoring alignment of a test strip. As a solution, the patent proposes the method as defined in claim 1, which credibly solves the posed problem.

42. Appellant II's argument that it was obvious to a person skilled in the art to replace the black ink in the method of document (6) by an infrared dye as described in any of documents (1), (2) and (4) fails to convince the board. While a person skilled in the art seeking for an alternative to the method of document (6) could, in principle, replace the black ink by any of the different dyes suggested in documents (1), (2) and (4), the board cannot see why the skilled person would consider in particular an infrared dye, as this would require to adapt the detection device described in document (6) by adding to the first and second reading units a third dedicated reading unit suitable for measuring reflectance of infrared radiation. This would only increase the complexity (and the price) of the detection apparatus, without bringing any apparent further advantages in accuracy in comparison to the method described in document (6).

43. The board is not persuaded that, in view of the above, a person skilled in the art had an incentive to replace the black bar code of document (6) by an infrared dye. He/she would be rather deterred from doing it because this would require additional technical means and increase the complexity of the measurement.

44. The board thus concludes that the method of claim 1 was not obvious to a person skilled in the art, within the meaning of Article 56 EPC. This confirms the opposition division's finding.

Conclusion

45. Having considered the arguments put forward by the parties in appeal proceedings, the board sees no reason to set aside the decision under appeal.