T 0592/99 (Matrix-formulation/EURO-CELTIQUE) 01-08-2002

I. European patent No. 0 624 366, based on European patent application No. 94 303 128.6 was granted on the basis of 7 claims.

Claim 1 reads as follows:

"A controlled release, oral pharmaceutical preparation suitable for dosing every twelve hours containing 50 to 400mg of tramadol or pharmaceutically acceptable salt thereof (calculated as hydrochloride) in a controlled release matrix, the matrix containing between 1 and 80% w/w of one or more hydrophilic or hydrophobic polymers, preferably a cellulose ether, and having the following dissolution rate in vitro when measured using the PH. Eur. Paddle Method at 100rpm in 900ml 0.1 N hydrochloric acid at 37°C and using UV detection at 270nm ;

between 5 and 50% (by weight) tramadol released after 1. hour,

between 10 and 75% (by weight) tramadol released after 2. hours,

between 20 and 95% (by weight) tramadol released after 4. hours,

between 40 and 100% (by weight) tramadol released after 8. hours,

more than 50% (by weight) tramadol released after 12. hours,

more than 70% (by weight) tramadol released after 18. hours,

more than 80% (by weight) tramadol released after 24. hours."

II. Seven Oppositions were filed against the granted patent.

In addition to the grounds of opposition under Article 100(a) EPC an objection under Article 100(c) EPC was raised on the grounds that the feature "...the matrix containing between 1 and 80% w/w...polymers", extends beyond the content of the application as filed.

III. By a decision announced on 27 April 1999, and posted with written reasons on 9 June 1999, the Opposition Division revoked the patent under Article 102(1) EPC.

In the Opposition Division's view the subject-matter of the main request (the set of claims as granted) and the first and second auxiliary requests did not comply with Article 123(2) EPC.

More particularly, it was pointed out that the term "...the matrix containing between 1 and 80% w/w...polymers" in claim 1 of the main request was a clear technical feature but found no basis in the application as originally filed. The application as originally filed disclosed a preparation containing 1 to 80% polymer not excluding other ingredients in the final preparation. Accordingly, the amendment relating to a polymer content in the matrix instead of the preparation changed the polymer content. There was also no contradiction between claim 1 and dependent claim 5 defining a dosage form of the preparation.

The same reasoning applied to the first auxiliary request which included in line 4 of claim 1 as granted (page 11, line 46 of the specification) after the wording "...preferably a cellulose ether...", the further amendment "the w/w basis being weight of the polymer per weight of the preparation".

The amendment to the second auxiliary request implying that the terms "matrix" and "preparation" should mean the same product was also not derivable from the application as originally filed.

The description including the examples as originally filed left no doubt that the matrix should be regarded as something like a container which together with the other ingredients made up the preparation.

IV. The Appellant appealed against this decision.

On the 2 July 1999 Respondent 03 (Opponent 03) withdrew as a party to the opposition and appeal proceedings.

With its grounds of appeal filed on 11 October 1999, the Appellant filed two auxiliary requests. The first auxiliary request corresponded as regards content to the first auxiliary request before the first instance and was presented as a correction under Rule 88 EPC. The wording of claim 1 of the second auxiliary request corresponded to claim 1 as granted with the additional words "...provided that the preparation must contain between 1 and 80% w/w of the one or more hydrophilic or hydrophobic polymers."

Oral proceedings took place on 1 August 2002 during which the Appellant withdrew its first auxiliary request filed with the grounds of appeal. During the oral proceedings the Appellant presented the following question to be referred to the Enlarged Board of Appeal:

"Where an amendment is made to a claim by reducing a stated range in the claim and where

(A) that reduced range is not identified in the application as filed, and

(B) the reduction does not provide a technical contribution to the subject-matter of the claimed invention

does that amendment extend the content of the application as filed within the meaning of Article 123(2) EPC ?"

V. The arguments of the Appellant, both during the written procedure and at the oral proceedings, may be summarised as follows:

The limitation regarding the 1 to 80% of one or more hydrophilic or hydrophobic polymers was introduced into claim 1 as a result of an interview with the first Examiner during the examination procedure. The choice of the wording regarding the allegedly wrong weight basis for the polymers, however, was accidentally introduced. The Examiner did not object to the wording introduced.

To read claim 1 in isolation, as was done by the Opposition Division could not be correct particularly having regard to the requirements of Article 69 EPC and the outcome of decision T 860/93. The patent as a whole made it clear that the weight per weight (w/w) basis is weight of the polymer per weight of preparation rather than weight of polymer per weight of matrix. This was supported by reference to claim 5 in which the product might contain as little as 1% of alkyl-celluloses with a w/w basis polymer/preparation. The bottom limit of 1% w/w in claim 1 must therefore be read as weight of polymer per weight of preparation since otherwise claim 5, which was dependent on claim 1, claimed a product outside the scope of claim 1.

In the alternative, if claim 1 was indeed to be read in isolation as specifying a w/w basis of polymer per matrix, reference was made to decision G 1/93 of the Enlarged Board of Appeal and in particular to the general guidance it provided on the underlying principles of equity. The overall purpose of Article 123(2) and (3) EPC was to create a fair balance of interests, as explained in paragraphs 8 and 9 of G 1/93, and having regard also to the effect of Article 69(2) EPC as explained in paragraph 10.

As for the requirement that the feature in claim 1 "...the matrix containing 1 to 80% of one or more hydrophilic or hydrophobic polymers..." should be an undisclosed feature only limiting the scope of protection, it was only an undisclosed feature to the extent that the weight basis is that of the matrix and not that of the preparation. This change did not provide a technical contribution in the sense for example of creating an inventive selection but merely excluded protection for a small part of the original subject-matter and accordingly did not adversely affect the interests of third parties as also required by decision G 1/93.

It was particularly to be noted that an upper limit of 80. wt% polymer/matrix was not greater than an upper limit of 80 wt% polymer/preparation. Considering for instance the product of Example 1, the matrix had a film coating which amounted to about 3 wt% of the product and typically the matrix amounted to 97 wt% of the product. As such, an upper limit of 80 wt% polymer/matrix approximated to an upper limit of 77,6 wt% polymer/preparation. Moreover, for a product which consisted solely of the matrix (film coating being optional), the figures were the same regardless of how the weight basis was expressed. Similarly a lower limit of 1 wt% polymer matrix was not greater than a lower limit of 1 wt% polymer preparation. For a film coated product a typical lower limit of 1 wt% polymer/matrix approximated to a lower limit of 0.97. wt% polymer/preparation. The amount of 0.97 wt% was within the limits of what is meant by 1 wt% since clearly an experimental determination of value of 0.97. wt% is within the rounded meaning of 1 wt%. On the basis of the proposed wording of claim 1 of the second auxiliary request it was in any case certain that there was no extension of the protection at the bottom end of the range. Considering an imaginary product weighing 100 mg with a coating of 3 mg, the figures for polymer per preparation were 1 mg in comparison with 0.97 mg polymer per matrix for the lower limit of 1 wt% and 80. mg polymer per preparation in comparison with 77,6 mg polymer per matrix for the upper limit of 80. wt%.

Regarding the overall composition of the preparation including the amount of tramadol, it was necessary to take into account both the clear technical information on page 2, line 46 of the specification that "the active ingredient in the preparation ... may suitably be incorporated in a matrix ... that affords controlled release tramadol ..." and also the fact that "alternatively, normal release matrices having a coating which provides for controlled release ... may be used."

Having regard to example 1 of the patent in suit, it was clear that the accidental change of weight basis disclaimed not only a negligible part of the composition but also only a small part of the release profile and thus merely excluded protection for a small part of the subject-matter of the claimed invention as covered by the application as filed. The adding of such feature could not reasonably be considered to give any unwarranted advantage to the Patentee (Appellant). Nor did it adversely affect the interests of third parties.

It was emphasised that the burden on proof was on the Respondents to show what was the technical contribution resulting from an accidental change of the weight basis.

Finally, it was strongly denied that the alleged change in the claimed release profile resulting from the change in the weight basis for the polymer content of the preparation formed part of the common general knowledge in the art.

Therefore, in the light of Headnote 2 of the decision G 1/93 the ground for opposition under Article 100(c) did not prejudice the maintenance of the patent in suit which included the feature in question.

VI. The Respondents' arguments may be summarized as follows:

In the circumstances of the present case none of the criteria set out in decision G 1/93 were fulfilled, particularly since the change of the weight basis in the present case had a drastic effect on the bottom end of the range of polymer content of the preparation and the matrix.

Contrary to the Appellant's assertion the following points had to be to taken into account:

(i) The patent in suit did not provide any technical information as to the meaning of the term matrix in claim 1;

(ii) claim 1 as granted did not relate to preparations containing exclusively 97 wt% of matrix material and 3 wt% of a coating;

(iii) the active ingredient tramadol did not form part of the matrix (-material) as such;

(iv) a change of the matrix composition caused a change of the release profile;

(v) the application as originally filed allowed a matrix in the form of a component consisting 100% of polymer material whereas claim 1 as granted necessarily required a minimum of 20 % of other components of the matrix material.

Points (iv) and (v) alone showed that the weight basis for the polymer content in claim 1 provided a technical contribution to the subject-matter of the claimed invention in the form of a functional effect on the preparation as such.

Moreover, the 100 mg tablet forming the basis for the Appellant's calculation but containing 26 wt% of matrix material of the total preparation instead of the Appellant's 97 wt%, would then contain 0.26 mg polymer at the bottom end range of 1% polymer per matrix material, an amount much lower than the 1 mg polymer calculated on the basis of the originally disclosed weight basis in relation to the total preparation.

The figures produced on the basis of simple calculation also clearly demonstrated that the feature in claim 1 as granted relating to the weight basis of the polymer content provided a technical contribution to the subject-matter of the claimed invention in the form of a limiting but originally undisclosed feature which cannot be deleted without offending Article 123(3) EPC.

Further, there was neither a lack of clarity nor a contradiction between the wording of independent claim 1. and dependent claim 5 which could give rise to the Appellant's interpretation of the weight basis of the polymer in the preparation. Claim 5 in fact represented a preferred embodiment of a dosage form of the preparation of claim 1 by limiting the type of polymer and polymer content such that the polymer content could not fall below the lower limit of 1% of polymer in the matrix.

VII. The Appellant requested that the decision under appeal be set aside and that the patent be maintained either unamended or on the basis of claim 1 of the second auxiliary request filed with the grounds of appeal on 11. October 1999 and claims 2 to 7 as in the granted patent and dependent on that new claim 1 (the only auxiliary request: the first auxiliary request having been withdrawn - see IV above).

The Respondents requested that the appeal be dismissed.