T 0453/08 (Cross linked polyvinyl alcohol microspheres/BIOSPHERE MEDICAL) 17-01-2012

Reasons for the Decision

1. Admissibility

1.1 The appeals are admissible.

1.2 Admission of the requests into the proceedings

1.2.1 The admission of changes to a party's submission after the filing of the statement of grounds of appeal and the reply thereto is, as specified by Article 13(1) RPBA, at the board's discretion and depends upon the circumstances of the case under consideration. According to Article 13(1) RPBA, the criteria to be considered when exercising this discretion are inter alia the complexity of the new subject-matter, the current state of the proceedings and the need for procedural economy. Account is taken of whether they could have been filed earlier, and if so, the reasons why they were not (see R 16/09 of 19 May 2010, points 2.2.4 and 2.2.11). Moreover, the amendments should be of clear and simple nature and prima facie allowable (T 87/05 of 4 September 2007, point 2 of the reasons). A general principle is that the later the requests are filed, the less likely the requests will be held to be admissible.

1.2.2 The main request and auxiliary requests 2, 3, 8 and 9 were all filed with the letter dated 6 July 2001 at a late stage in the proceedings, as the main request and auxiliary requests 1, 2, 7 and 8 respectively.

1.2.2.1 The main request differs from the main request filed on 8 March 2007 in that the claims drafted as "product for use claims" (claims 19 to 21), which had been objected to in the board's communication dated 11 May 2011, have been deleted. This amendment constitutes a direct and clear response to an objection raised by the board of its own motion.

Moreover, process claim 19 has been amended by the introduction of a step h), namely a sterilizing step, and by the incorporation of a reference to the product of claim 1. These amendments represent a response to the board's communication, since the board had observed that the process claim was an independent claim and that the product obtained was not necessarily the product of claim 1. Furthermore, the amendments had been introduced to prevent further objections caused by the grounds for opposition. Thus, the amendments are prima facie a response to the grounds for opposition.

Consequently, the amendments to the main request are occasioned by developments during the appeal proceedings and prima facie address the issues raised by the board without giving rise to new ones and without adding complexity to the case under consideration. They constitute a direct, clear and fair attempt to respond to the board's communication. Therefore, although submitted after the filing of the statement of the grounds of appeal, the main request is admitted into the proceedings.

1.2.2.2 Auxiliary request 2 differs from auxiliary request 3 as upheld before the opposition division in an analogous manner to the way in which the main request differs from the previous main request (see point 1.2.2.1 above).

Consequently, auxiliary request 2 is admitted into the proceedings for analogous reasons to those stated above for the main request.

1.2.2.3 Auxiliary request 3 basically differs from auxiliary request 2 in that the expression "under microscopic examination" has been added to claim 1. The other amendments are analogous to the amendments made in auxiliary request 2.

Thus, the amendments introduced constitute a direct response to the board's communication.

Consequently, auxiliary request 3 is admitted into the proceedings.

1.2.2.4 Auxiliary request 8 differs from the main request as filed on 8 March 2007 in that all the product claims relating to the microspheres per se (previous claims 1 to 9) have been deleted.

Additionally, new claim 1 differs from independent claim 10 of the main request in that it incorporates the feature "wherein the difference in diameter between the microspheres is from 0 mym to 150 mym". This latter amendment in claim 1 represents a direct response to the board's observations in relation to the broad range of diameter size in the claims.

Furthermore, as for the main request, process claim 10 comprises a reference to the microspheres as "defined in claim 1" and the "product for use claims" have been deleted (claims 19 to 21). Therefore, the reasons given above for the main request apply mutatis mutandis to auxiliary request 8.

Consequently, auxiliary request 8 is admitted into the proceedings.

1.2.2.5 Auxiliary request 9 differs from the main request filed on 8 March 2007 in that all the product claims have been deleted.

The deletion of the product claims is seen as a direct response to the objections to them raised by the board. As already mentioned, the set of claims as granted contained an independent process claim.

The introduction of a step h), namely a sterilization step, in process claim 1 is a clear and simple response to the board's communication.

Consequently, auxiliary request 9 is admitted into the proceedings.

1.2.3 Auxiliary request 1 was submitted during the oral proceedings before the board, after the discussion on the novelty of the main request had taken place. This request was therefore submitted at a terminally late stage of the procedure.

Auxiliary request 1 basically differs from the main request in that claims 1-9 relating to the microspheres per se have been deleted. Moreover, the new claim 1, which corresponds to the previous independent claim 10, has been amended by the incorporation of the feature of dependent claim 13.

Additionally, independent process claim 9 has been amended by introducing the following feature: "useful for embolization, which have a diameter ranging from 10 mym to 2,000 mym, and are substantially spherical and sterile".

The discussion during the oral proceedings before the board of the novelty of the main request vis-à-vis documents (3) and (9) did not justify the filing of a new request. The novelty of the main request had been contested during the opposition proceedings and in the written proceedings in appeal. The assessment of the novelty of the subject-matter claimed in any requests vis-à-vis documents (3) and (9) could not have taken the appellant-proprietor by surprise, since both documents had been on file since the beginning of the procedure, and no new issues were introduced during the oral proceedings before the board in this respect.

Furthermore, the re-drafting of the new claims which originate from a combination of prior claims 10 and 13 constitutes a shifting of the invention at a very late stage of the proceedings. The introduced amendments would have occasioned a new discussion on novelty and raised, prima facie, new issues in relation to the clarity (Article 84 EPC) of the terms in the new context of the claim.

Admitting new auxiliary request 1 during the oral proceedings would have put into question the basic principles governing fair inter parte proceedings. Inter parte appeal proceedings cannot be seen as a means for re-examining the application, nor does the patent proprietor have the absolute right to file sequential auxiliary requests in the course of the discussions before the board of appeal.

The appellant-proprietor should have been prepared to respond earlier to the objections of lack of novelty by filing an adequate set of auxiliary requests.

Accordingly, auxiliary request 1 is not admitted into the proceedings.

1.2.4 Auxiliary request 4 was filed as auxiliary request 3 with the letter dated 6 July 2011, i.e. at a late stage in the proceedings.

Claim 1 of auxiliary request 4 differs basically from claim 1 of the main request filed on 3 March 2007 in that the feature "wherein the microspheres have a smooth surface such that no attrition occurs and no small-sized particles are generated from said microspheres" has been included at the end of the claim.

The feature "wherein the microspheres have a smooth surface such that no attrition occurs and no small-sized particles are generated from said microspheres" originates from the description and was not present originally in any of the granted claims. This amendment raises new issues which would necessitate a complex assessment of the content of the description and is considered to be prima facie not allowable under Article 84 EPC.

Accordingly, auxiliary request 4 is not admitted into the proceedings.

1.2.5 Auxiliary request 5 was filed with the letter dated 23 December 2011, i.e. at a very late stage in the proceedings.

Claim 1 of auxiliary request 5 differs from claim 1 of auxiliary request 4 filed with the letter of 6 July 2011 in that the word "and" has been replaced by the word "or" in the expression "for prophylactic and therapeutic embolization". This particular amendment can be seen as remedying an obvious error.

Auxiliary request 5 does not contain claims of the product category, since claims 1-18 have been reworded as use claims in the "Swiss-type" form.

The justification given by the appellant-proprietor was that the rewording of the product claims as use claims represents a fair attempt to overcome the appellant-opponent's objections of lack of novelty regarding the product claims.

However, as mentioned in point 1.2.3. above, the objection of lack of novelty raised against the product claims was long known to the appellant-proprietor, and was already present in the opposition proceedings and pursued again by the appellant-opponent in its grounds of appeal.

As a matter of fact, it was clear from the beginning that the assessment of novelty would be a major issue in the present case. Thus, it was the appellant-proprietor's duty to provide as early as possible, for a complete defence, all possible fallback positions, inter alia a rewording of the product claims as use claims. This was not the case with auxiliary request 5, which was filed at a late stage in the proceedings.

Nor, moreover, can the filing of said request be seen as a last chance attempt, since the issue of novelty had not been decided prior to the oral proceedings before the board and had not yet been assessed by the board at the time of filing.

In inter partes appeal proceedings the principle of fairness and equity must apply to all parties. Thus, in the absence of any good reasons for its late filing, i.e. exceptional circumstances that justify the late filing, auxiliary request 5 is not admitted into the proceedings.

1.2.6 Auxiliary request 6 was filed with the letter dated 6 July 2011 as auxiliary request 5.

It basically differs from the main request as filed on 8 March 2007 in that the feature "and wherein the microspheres are in hydrogel form and comprise 0.5% to 20% by weight polyvinylalcohol" has been added to claim 1. Claim 10 has been amended by the incorporation of a reference to claim 1, and the process claim has been amended as mentioned for the main request in point 1.2.2.1 above, i.e. the "product-for-use" independent claims submitted in the course of opposition proceedings (claims 19 to 21) have been deleted.

Even if it is considered that the amendment introduced in claim 1 was made in an attempt to overcome new objections raised in the board's communication, it represents a real shifting of the invention and opens up new issues, especially regarding the clarity of the claim (Article 84 EPC).

Consequently, the amendments introduced in claim 1 are not of a clear and simple nature, and are not prima facie clearly allowable. Auxiliary request 6 is not admitted into the proceedings.

1.2.7 Auxiliary request 7 was filed with the letter dated 6 July 2011 as auxiliary request 6.

It basically differs from the main request as filed on 8 March 2007 by the addition of the feature "wherein the difference in diameter between the microspheres is from 0 mym to 150 mym, when the particles are in the form of an injectable suspension" in claim 1.

The other modifications in product claim 10 and process claim 19, as well as the deletion of the "product for use" claims, are analogous to the modifications mentioned for auxiliary request 6 (point 1.2.6. above).

The feature introduced in claim 1 of auxiliary request 7 is merely an optional and conditional feature which does not clearly restrict the claim vis-à-vis claim 1 of the main request, since the claimed microspheres are not necessarily in the form of a suspension.

Consequently, auxiliary request 7 is not admitted into the proceedings.

1.2.8 Auxiliary requests 10 and 11 were submitted very late, with the letter dated 9 December 2011, as auxiliary requests 9 and 10.

The filing of these requests is not justified by exceptional circumstances, since they do not respond to any new argument by the board or submission by the appellant-opponent. No other reason for their late filing was given by the appellant-proprietor than that they were an attempt to more clearly define the subject-matter claimed. This is, however, not a justification for late filing, since there had been opportunities to file such auxiliary requests far earlier.

Additionally, each claim 1 of these auxiliary requests has been newly reformulated as a "product by process" claim (obtainable by the process as defined in any of the process claims 19 to 35). On the other hand, process claim 19 of both requests relates to a process for making microspheres according to claim 1. Thus, the reformulation of the independent claims in the form of loop references raises prima facie new issues in relation to the requirement of clarity (Article 84 EPC).

Therefore, amended claim 1 of auxiliary requests 10 and 11 is prima facie not allowable.

Consequently, auxiliary requests 10 and 11 are not admitted into the proceedings.

2. Admission of additional documents and experimental data

2.1 The opposition division did not admit into the proceedings documents (17) to (19), which were filed on 10 October 2007 (Rule 71a EPC 1973). The division considered that these documents were not prima facie relevant for novelty and inventive step and that they were not more relevant than the documents already on file.

The board considers that the opposition division was correct in exercising its discretionary power not to admit these documents under Rule 71a EPC 1973 by taking into account the circumstances of the case and by giving precedence to the criteria of relevance. Indeed, the board cannot discern any new issue which has not been discussed before the opposition division and which could justify the finding of a misuse in the opposition division's exercise of discretion.

Consequently, documents (17) to (19) are not admitted into the proceedings.

2.2 Document (26) was filed with the letter of 9 December 2011, i.e. at a late stage in the appeal proceedings. Said document is a print of a Google search on "smooth microspheres" performed in 2011. This Google search is neither pertinent nor relevant to the present appeal case and document (26) is therefore not admitted into the proceedings.

2.3 Document (22) was filed with the appellant-opponent's statement of the grounds of appeal and can be considered as a reaction to the arguments of the decision of the opposition division (Article 12 RPBA).

Although document (22) may possibly not be relevant for the decision, it is pertinent and therefore is admitted into the proceedings.

2.4 Document (23) was filed with the appellant-opponent's grounds of appeal. The document is an experimental report concerning the preparation of microspheres of polyvinylalcohol according to document (3). It was filed in order to support the appellant-opponent's arguments in relation to the novelty assessment. Moreover, the admissibility of document (23) was not disputed by the appellant-proprietor. Consequently, document (23) is admitted into the proceedings.

2.5 Experimental report (25) was filed on 27 June 2011 by the appellant-opponent in response to the board's communication. Its content is prima facie relevant for the assessment of novelty vis-à-vis document (3) and the appellant-proprietor's arguments in relation to the non-enabling disclosure of document (3). Moreover, the appellant-proprietor has been able to assess its content and to reply to it.

Consequently, experimental report (25) is admitted into the appeal proceedings.

2.6 Experimental report (27) was filed on 9 December 2011 by the appellant-proprietor. It represents an attempt to respond to experimental report (25). Its content is prima facie relevant for the assessment of novelty vis-à-vis document (3). Consequently, experimental report (27) is admitted into the proceedings.

2.7 Document (24) was filed by the appellant-opponent with the letter of 21 April 2011 in an attempt to respond to the appellant-proprietor's arguments in appeal proceedings. This document discloses spherical cross-linked polyvinylalcohol beads (see Title; abstract; page 11 third paragraph). Document (24) is therefore prima facie relevant for the assessment of novelty and/or inventive step. Moreover, it was submitted well enough in advance of the oral proceedings before the board of appeal, which means that the appellant-proprietor had sufficient time to prepare his reply. Document (24) is admitted into the proceedings.

3. Main request - novelty

3.1 The main request was objected to by the appellant-opponent on the basis of Article 123(2) EPC and Rule 80 EPC in the course of the oral proceedings before the board of appeal. However, the board sees no need to conclude on these two issues for the main request, since the request fails for other reasons, as will become evident from the paragraphs below.

3.2 Document (3)

3.2.1 Document (3) discloses cross-linked polyvinylalcohol microspheres which are used as particulate emboli, and the method of preparation thereof. The microspheres have a size ranging from 100 to 1,500 mym (Abstract; Figures 1-4) and have as constituent cross-linked polyvinylalcohol of "low molecular weight" type (see page 68, Materials). Two types of microsphere are made, namely with and without barium sulphate (see page 68, Methods). The microspheres disclosed in document (3) have a substantially spherical shape, since the document states that "this method led to the formation of nonaggregatory, predominantly spherical beads in less than one hour" (page 69, left-hand column, end of first paragraph) and that "Figure 3 shows the SEM of the PVA microsphere having a barium sulphate content of 40 wt%. The predominantly spherical shape of the microspheres could be ascertained from the photomicrograph" (see page 69, right column).

The microspheres disclosed in document (3) are inevitably sterile, since document (3) states that "it was observed that the barium sulphate was firmly trapped inside the microspheres as it did not leach out on prolonged standing in water, on sonication or on steam sterilization in 0.9% saline" and "as in the case of barium sulphate, there was no migration of methyl iothalamate when the microspheres were subjected to sonication or steam sterilization" (see pages 69, right-hand column, and 70, left-hand column, first and second paragraphs).

According to document (3), the microspheres are "presumed to perform favourably in vascular occlusion" (see page 72, conclusions). The formation of emboli on arteries using heparinized calf blood is explicitly mentioned on page 71 of document (3).

Consequently, document (3) anticipates all the features of the subject-matter claimed in claim 1 of the main request.

3.2.2 The relevance of document (3) was contested by the appellant-proprietor in relation to the "sterile" character of the microspheres and their "suitability for embolization". Moreover, the appellant-proprietor submitted that the content of document (3) concerned a non-enabling disclosure.

As stated above, document (3) studies the behaviour of the BaSO4 or methyl iothalamate loaded microspheres on steam sterilization (see page 70). The explicit sterile character of the microspheres cannot therefore be denied.

As regards the term "useful for embolization" in claim 1 of the main request, it only reflects a suitability of the claimed microspheres for embolization. Document (3) mentions the use of the microspheres as emboli several time (Abstract; pages 71 and 72). Furthermore, there is no reason to doubt the suitability for embolization of microspheres having the same size and shape as the microspheres of the present invention.

As regards the argument of lack of enablement of the disclosure of document (3), three documents were filed by the parties with experiments repeating the process of preparation of the microspheres disclosed in document (3), namely experimental reports (23), (25) and (27).

The appellant-proprietor filed in support of its argumentation of lack of enablement of the disclosure the experimental report in document (27) and based its argumentation of non-enablement mainly on the results of the experimental reports in documents (23) and (27).

The experiments in document (27) attempted to repeat the process of document (3) for making microspheres with BaSO4 but did not manage to produce any microspheres. The result of the experiment was a mass of fibres which stuck to the impeller and which may not be regarded as microspheres. The content of document (27) is, however, not sufficient to show a lack of enablement of the disclosure of document (3).

The polyvinylalcohol used in document (27) has a molecular weight of 31 to 50 kDa, which cannot qualify as a low molecular weight PVA and is higher than the low molecular weight of the PVA used, for instance, in the experiment in document (23). The board is therefore not convinced that the polyvinylalcohol used in document (27) is the same as that used in the experiments in documents (3) or (25) and that it can be considered a low molecular weight polyvinylalcohol. The presence of a heating step at 50ºC, absent from the process in documents (3), (23) or (25), in order to dissolve the polyvinylalcohol, is an indication contrary to the appellant-proprietor's assertions.

Consequently, the technical information of document (27) does not disprove that the process of document (3) is enabling.

Additionally, the experiments in document (23) repeat the process of preparation of the microspheres of document (3) without BaSO4. The microspheres obtained are shown to be smooth and spherical (see "Results" and "Conclusion"). The steering speed used during the process was lowered to 400 rpm, instead of 2,000 rpm as in document (3), since the "dispersions were unstable at 2,000 rpm and produced many particle fragments". The beaker was of the same size in both documents (3) and (23) and the stirrer was in document (3) a "half-moon stainless steel paddle stirrer" and in document (23) a PTFE stirrer (see "Comments on method" on page 3). The size of the stirrer in document (3) was not stated. Another difference consisted in the nature of the oil phase used in the process.

The differences in the processes cannot however serve to be regarded as evidence for a lack of enablement of the process in document (3). Document (3) is silent about the size of the stirrer, but it can be expected to have an influence on the stirring speed which can be used. A lowering of the stirring speed down to 400 rpm is a self-evident adaptation between the stirrers available today and the size of the beaker.

On the other hand, document (23) shows explicitly that smooth and spherical microspheres had actually been obtained (Figure 1).

The experiments in document (25) repeat the process of making the microspheres comprising BaSO4 of document (3). The successfully produced microspheres appear smooth and spherical under microscopic examination (Figure 1). Apart from the differences in the oil phase, the products and process conditions in the experiments of documents (3) and (25) are comparable. Thus, in view of the experimental results set forth in document (25), the board does not see any reason to question the enablement of the preparation process in document (3). As regards the argument concerning the feasibility of the stirring step in a beaker of 100 ml, document (25) shows that it appears possible to reach a speed of 2,000 rpm in a beaker of the chosen size with an appropriate stirrer.

3.2.3 Consequently, document (3) is novelty-destroying for the subject-matter of claim 1 of the main request.

3.3 Document (9)

3.3.1 Document (9) (understood to refer to the English translation submitted as document 9.2) discloses microspheres for embolization of the hepatic artery made from cross-linked polyvinylalcohol (see Abstract and paragraph I.2., pages 2-3). The microspheres have a size of 150+/-30 mym (page 4, par. VI). Furthermore, the microspheres are "sphere-like particles under the optical microscope" (page 6). The microspheres are sterilized (page 4, paragraph IV, "Test of sterilization") and used for embolization (page 4, paragraph VI, "Test of embolization of the hepatic artery", and paragraph VII).

Consequently, document (9) anticipates all the features of the subject-matter claimed in claim 1 of the main request.

3.3.2 The relevance of document (9) was contested by the appellant-proprietor for lack of enablement of its disclosure.

According to the appellant-proprietor, document (9) gives only a general teaching regarding the manufacture of the microspheres of polyvinylalcohol. It submitted that the process used in document (9) concerns an emulsification polymerization, without giving any indication regarding the catalyst, the nature of the water in oil emulsion, or the dispersant.

However, document (9) is a scientific document which relates to the use of microspheres for embolization and to the comparison of different types of microsphere for said use. Thus, the main focus of interest of document (9) is the studies concerning the use of the microspheres in embolization and not the specific details of their manufacturing process. However, it is part of the general knowledge of the skilled person to know how to prepare PVA microspheres and which catalysts to select for emulsion polymerization. Document (5) confirms that there are a number of catalysts, emulsions and emulsifying agents useful for the polymerization and cross-linking of polyvinylalcohol (see document (5) col. 3, line 58 to col. 4, line 24 and example 1).

The board is convinced that the skilled person would be able to reproduce the microspheres disclosed in document (9), as shown by the photographs on page 6, following the manufacturing process mentioned therein.

Consequently, document (9) is novelty-destroying for the subject-matter of claim 1 of the main request.

3.4 For the reasons given in points 3.2 and 3.3 above, the main request fails for lack of novelty of claim 1 (Articles 52(1) and 54 EPC).

4. Auxiliary request 2 - Article 84 EPC

4.1 Claim 1 of auxiliary request 2 has been amended to include the expression "and wherein the surface of the microspheres appears smooth under less than 1,000-fold magnifications" in order to overcome the lack of novelty of the main request.

4.2 Therefore, the question to be answered with respect to the clarity of the claim within the meaning of Article 84 EPC is whether it is possible to determine whether or not a particular embodiment falls within the claim.

Even if it is considered in favour of the appellant-proprietor that the skilled person would be able in most cases to determine whether or not the surface of a microsphere is smooth, the condition of the appearance of smoothness is relative and subject to the observer and to the conditions under which it is observed. In order to establish a valid comparison between different microspheres having a certain degree of smoothness, a standard definition or a standard test would be required.

However, the claim does not even state the lowest magnification possible for observing the microspheres, nor does the description disclose any standard method.

As a matter of fact, the description does not give any definition of the desired smoothness, nor do the examples illustrate that the microspheres are indeed smooth. There is indeed no observation reported on the microspheres prepared in the examples. Therefore, it is not possible to ascertain whether the surface of the claimed microspheres has to be perfectly smooth or if a certain number of surface irregularities may be tolerated.

In view of above, claim 1 of auxiliary request 2 does not fulfil the requirement of Article 84 EPC.

4.3 According to the appellant-proprietor, the term "smooth" is clear to the skilled person and serves to differentiate the claimed microspheres from those in the prior art.

It submitted that the definition of smoothness is common and was given in the description, as "no attrition occurs and no small-sized particles are generated from said microspheres" (page 8, lines 11-13 of the application as filed) and that the surface of the microsphere should appear smooth at any magnification below the claimed magnification.

However, as explained in point 4.2 above, the subjective character and relativeness of the smoothness at any magnification below 1,000-fold cannot serve as a clear limitation of the claimed microspheres vis-à-vis the prior-art microspheres.

Moreover, the property presumably conferred as a result of the smooth surface of the microspheres, namely that "no attrition occurs and no small-sized particles are generated from said microspheres", renders the appreciation of the required smoothness even more unclear in the absence of explanations and experimental modalities in the form of a reproducible test in the application as filed.

The reference by the appellant-proprietor to the smooth beads shown in document (24) serves only to show that the term "smooth" is known, and is otherwise a further illustration of the subjectivity and relativeness of said term. This document shows pictures of "smooth" beads, but lacks any information on the magnification used for the photographs and does not provide any further definition of the term (page 11, right-hand column, "Preparation of PVAc and PVA beads; page 12, Fig. 2).

4.4 Consequently, auxiliary request 2 fails to meet the requirements of Article 84 EPC.

5. Auxiliary request 3 - Article 84 EPC

Claim 1 of auxiliary request 3 merely differs from auxiliary request 2 in that the term "under microscopic examination" has been added to claim 1.

Therefore, the reasons stated above for auxiliary request 2 apply mutatis mutandis to auxiliary request 3. The addition of the term "under microscopic examination" in claim 1 of auxiliary request 3 does not give any further indication as to a standard method for determining whether or not the particles are sufficiently smooth.

Thus, auxiliary request 3 fails, since claim 1 does not fulfil the requirements of Article 84 EPC.

6. Auxiliary request 8 - Article 84 EPC

6.1 Claim 1 of auxiliary request 8 relates to an injectable and sterile composition comprising cross-linked polyvinylalcohol microspheres. Additionally, claim 1 was amended by the introduction of the expression "wherein the difference in diameter between the microspheres is from 0 mym to 150 mym".

The appellant-opponent objected to auxiliary request 8 under Article 123(2) EPC. However, the board does not see any need to come to a decision on this point, in view of the fact that the request fails for other reasons.

6.2 The amendment to claim 1 introduces an inconsistency between the delimitation given in the claim for the size of the microspheres, i.e. a diameter ranging from 10 mym and 2,000 mym, therefore including microspheres with a diameter of less than 150 mym, and the fact that the difference in diameter may be from 0 mym to 150 mym, which renders the subject-matter of the claim unclear.

Moreover, the added feature introduces an unclear limitation to the size distribution of the microspheres, since the claim encompasses populations of microspheres having a uniform and narrow size, as well as populations having a multi-modal size.

Therefore, claim 1 of auxiliary request 8 does not fulfil the requirements of Article 84 EPC.

6.3 The appellant-proprietor argued that the term was comprehensible to the reader willing to understand, since it was clear how to measure the difference in diameter. In other words, the difference between the smallest and biggest particles should not be more than 150 mym.

Even if it were to be considered that the skilled person would know how to measure the difference in diameters, claim 1 encompasses particles having a diameter smaller than 150 mym (10 mym is the specific lowest limit) and presenting simultaneously a difference in diameter of up to 150 mym. The appellant-proprietor's arguments do not overcome the objection of lack of consistency, in particular for microspheres having such smaller size.

6.4 Therefore, auxiliary request 8 fails for lack of clarity under Article 84 EPC.

7. Remittal to the first instance (Article 111(1) EPC)

7.1 Auxiliary request 9 contains only process claims relating to the process of preparing microspheres of cross-linked polyvinylalcohol having a size ranging from 10 mym to 2,000 mym.

As a matter of fact, the set serving as a basis for the decision of the opposition division contained an independent process claim with no reference to the product of claim 1. In particular, the set of claims as granted contained an independent process claim 19.

The opposition division decided to maintain the patent in the amended form on the basis of the third auxiliary request as filed during the oral proceedings before the opposition division. This request comprised an independent process claim (claim 22) with no reference to the product claim.

The decision of the opposition division did not address the process claimed under Articles 54 and 56 EPC. Moreover, the minutes of the oral proceedings before the opposition division give no indication that the process claim had even been discussed during the oral proceedings before the department of first instance.

Consequently, the reasons for the maintenance of the process claim are neither stated in the decision nor are they implicitly apparent. Thus the process claimed in claim 1 of auxiliary request 9 has to be investigated on its own merits.

Consequently, the board uses its discretionary power under Article 111(1) EPC to remit the case to the department of first instance for further prosecution on the basis of a set of claims containing method claims only.

7.2 The appellant-opponent was not in favour of a remittal to the department of first instance since, in its opinion, the opposition division had tacitly maintained the process claim and the patentee had not been adversely affected by its decision. Moreover, it submitted that a remittal to the first instance would not be in the interests of procedural economy.

7.3 The board cannot follow the appellant-opponent's arguments against the remittal.

The appellant-proprietor does not know the reasons why the process claim was considered novel and inventive by the opposition division. To discuss the patentability of the process claims for the first time at the oral proceedings before the board of appeal would deprive the appellant-proprietor of the possibility to properly challenge the appellant-opponent's arguments.

In view of the fact that the decision of the opposition division has a fundamental deficiency, remittal to the first instance must be seen as a fair and equitable way of treating the parties. This aspect clearly outweighs the need for procedural economy.