T 2402/10 (Prostaglandin derivatives / Pfizer) 10-05-2012

Reasons for the Decision

1. The appeal is admissible.

2. Procedural matter

The Appellant requested the Board of Appeal to exercise its discretion in accordance with Article 111(1) EPC and to render a decision on all grounds of opposition raised by the Opponents although the issues of novelty and inventive step were not dealt with by the Opposition Division in the decision under appeal. None of the Respondents objected to this request. The Board furthermore notes that all Parties had requested acceleration of the opposition proceedings (see the Respondents' letters dated 22 October 2009, 5 October 2009 and 6 November 2009, respectively).

Taking particular account of the fact that all parties wish the opposition proceedings to be concluded without further delay, the Board has chosen to exercise its discretion under Article 111(1) EPC to examine on all opposition grounds raised by the opponents.

Main request

3. Amendments (Articles 76(1) and 123(2) and (3) EPC)

3.1 Claim 1 is based on the passage bridging page 7 and 8 of the application as filed in combination with page 8, lines 16 to 22 read with the disclosure of the prostaglandin derivative disclosed on page 6, line 21 (compound 9), and further limited to the treatment of human beings according to page 7, line 33.

The section of page 8, lines 16 to 22 of the application as filed, which relates to ophthalmological compositions for topical treatment of glaucoma or ocular hypertension obviously contains a clerical error in that only the symbol "my" is indicated for the unit of the dose of the prostaglandin derivative and the dose of the composition. This section reads "a dose of about 0.1-30 my in about 10-50 my of the composition". However, throughout the application as filed, the amount of the prostaglandin derivative is always specified by its mass while that of the composition by its volume. More particularly, the preceding section on page 7, line 22 to 34 relating to the method for treating glaucoma or ocular hypertension discloses that the composition to be contacted with the eye contains 0.1-30 myg of the derivative and that the treatment may advantageously be carried out in a that one drop of the composition corresponding to about 30 myl is administered to the patient's eye. Hence, it appears immediately that nothing else than a dose of about 0.1-30 myg of the derivative in about 10-50 myl of the composition was intended to be specified in the following section relating to the composition for that use. This finding is also in line with the experiments, where the concentration of the prostaglandin in the ophthalmological composition is always given in weight of active compound per volume of the composition (see page 8, line 24 to 28).

3.2 In the decision under appeal, the Opposition Division indicated that the paragraph of page 8, starting from line 24 cast a doubt on the interpretation of both "my" symbols in that it could not be decided whether they should really mean "micro" or whether "milli" was intended.

However, it clear that "milli" could not be intended, otherwise the passage page 8, lines 16 to 22 would have been inconsistent with the remainder disclosure the application as filed, in particular with the section of page 8, starting from line 24. In addition the symbol "my" designates "micro" and not "milli" which is symbolised by "m".

3.3 The Respondent objected that there was an uncertainty for the unit itself, i.e. it could be either a mass or a volume unit, all the more because the ophthalmological composition encompassed ointments, which were rather solids than liquids.

This argument does not convince the Board since the passage of page 8 is not specifically directed to ointments. Moreover ointments can also be quantified by their volume. It remains that in order to be consistent with the reminder disclosure of the application as filed, the sole possible reading is a concentration of the active component expressed in weight of active compound per volume of composition.

3.4 The Respondent further objected to that the passage of page 8 relating to the ophthalmological composition use was not disclosed in combination with the specific compounds (9).

However, the features relating to the ophthalmological composition for topical treatment of glaucoma or ocular hypertension are to be read in combination with any prostaglandin derivative disclosed in the application, thus inclusive compound (9).

3.5 Thus, the application as filed provides a proper basis for the subject-matter of claim 1 of the main request. Consequently, the requirement of Article 123(2) is fulfilled.

3.6 The present application was filed as a divisional application of European application 93109514.5, which in turn was filed as a divisional application of European application 89850294.3.

The description of the application as filed is identical to that of both European applications 89850294.3 and 93109514.5. The support of claim 1 is based exclusively in the description of the application as filed. Thus, the requirement of Article 76(1) EPC is also satisfied for claim 1 of the main request.

3.7 Claim 1 as granted was directed to C1-C10 alkyl ester of 13,14-dihydro-17-phenyl-18,19,20-trinor-PGF2alpha, thus covering the 13,14-dihydro-17-phenyl-18,19,20-trinor-PGF2alpha-isopropyl ester. Claim 1 of the main request is a Swiss-type claim directed to the use of this compound. Since the protection conferred by the product claim 1 as granted is larger than that conferred by the use claim 1 of the main request, the requirement of Article 123(3) EPC is therefore met, which finding was not contested.

4. Clarity (Article 84 EPC)

The appealed decision found claim 1 of the main request (then pending auxiliary request 7) met the requirement of Article 84 EPC (see point III above). Clarity was no longer contested in the appeal proceedings, nor does the Board see any reason to take a different view. Hence, it is unnecessary to go into more detail in this respect.

5. Insufficiency of disclosure

Although raised as ground for opposition by former opponents 3 and 4 against claim 1 as granted, this issue was no longer in dispute before the Board in view of the amendments made to the claim 1 of the main request. The Board is satisfied that the patent in suit discloses the invention in a manner sufficiently clear and complete to be carried out by a person skilled in the art.

6. Novelty

Lack of novelty raised as grounds for opposition by Respondent II and III against claim 1 as granted. In view of the amendments made to the claim of the main request, the Board is satisfied that the subject-matter of claim 1 is novel, already since none of the cited documents discloses the 13,14-dihydro-17-phenyl-18,19,20-trinor-PGF2alpha-isopropyl ester.

7. Inventive step

7.1 Closest prior art

Document (7) relates to the correlation between the prostaglandin F2alpha effects on rabbit intraocular pressure (IOP) and classical PGF2alpha receptor stimulation. It discloses the IOP potency rank order of several PGF2alpha derivatives including PGF2alpha, 13-14 dihydro PGF2alpha and 17-phenyl,18,19,20 trinor PGF2alpha.

The Board considers, in agreement with the Appellant and Respondent II and III that this document represents the closest prior art to the invention, and hence, the starting point for the assessment of inventive step.

In its notice of opposition, Respondent II indicated that documents (6) and (8) may also represent a starting point for inventive step. However, these documents relate to ester of PGF2alpha which are structurally more remote to Latanoprost than the 17-phenyl,18,19,20 trinor PGF2alpha disclosed in document (7). Therefore documents (6) and (8) are more remote to the claimed invention than document (7).

7.2 Technical problem underlying the patent-in-suit

The Appellant defined the technical problem underlying the invention as the provision of a further prostaglandin analogue having the ability to reduce intraocular pressure and treat glaucoma or ocular hypertension without exhibiting undesirable side effects, namely ocular irritation and hyperaemia.

7.3 Solution

As a solution to this problem, the patent-in-suit proposes Latanoprost which is characterized by a C-C single bond in position 13 and an isopropyl ester moiety.

7.4 Success

Tables V and VI of the patent-in-suit reveal that latanoprost (compound 9) had an intraocular pressure reducing effect, while tables III and IV showed the absence of ocular irritation and hyperemia for this compound. The Board is therefore satisfied that the technical problem have been solved by the proposed solution.

7.5 Obviousness

Finally, it remains to be decided whether or not the proposed solution to the problem underlying the disputed patent is obvious in view of the cited prior art.

Document (7) teaches that specific PGF2alpha derivatives, such as 13-14 dihydro PGF2alpha and 17-phenyl-18,19,20 trinor PGF2alpha have the ability to reduce intraocular pressure. However, this document does not tackle the problem of providing further derivatives, let alone gives any hint on how to achieve this goal. Hence, for this simple reason that document alone cannot point to the claimed solution for solving the technical problem underlying the patent-in-suit. Thus document (7) itself does not suggest the proposed solution.

In their notice of opposition, Respondents II and III argued that it was obvious to combine the structural characteristics of two PGF2alpha derivatives to arrive at the compound of the invention. However, in the field of drug design any structural modification of a pharmacologically active compound is, in the absence of an established correlation between structural features and activity, a priori expected to disturb the pharmacological activity profile of the initial structure (see T 643/96 point 4.2.3.3 of the reasons; T 548/91, point 6.4 of the reasons; both decisions not published in the OJ EPO).

Document (10) discloses that esters of PGF2alpha derivatives reduce intraocular pressure. Accordingly, even by combining the teaching of document (7) with that of document (10), namely by esterifying the PGF2alpha derivatives disclosed in document (7), the person skilled in the art would not have arrived at the solution proposed by the patent in suit which is also characterized by the presence of a single bond in position 13 of the PGF2alpha derivative.

Therefore, the Board comes to the conclusion that the subject-matter of claim 1 involves an inventive step within the meaning of Article 56 EPC.

8. Double patenting

Although not being a ground for opposition, the Respondent I objected to double patenting, since claim 1 of the patent-in-suit was amended during the opposition/appeal proceedings in such a matter that its scope was fully encompassed by the scope of the claims of the patent EP0364417B granted from the grand parent application. The subject-matter of claim 1 of the patent-in-suit was not substantially different from the subject-matter of the combination of claims 1, 9 and 14 of EP0364417B for the contracting state AT, BE, CH, DE, FR, GB, IT, LI, LU, NL, SE or of the combination of claims 1 and 15 for the contracting states ES and GR.

In G 1/05 (OJ EPO 2008, 271) and G 1/06 (OJ EPO 2008, 307) (both point 13.4 of the reasons), the Enlarged Board of Appeal accepted that a principle of prohibition of double patenting existed on the basis that an applicant had no legitimate interest in proceedings leading to the grant of a second patent for the same subject-matter. This requirement of "same subject-matter" was followed in the established case law of the technical boards of appeal regarding the question of "double patenting" (see e.g. T 1391/07, point 2.5 of the reasons; T 877/06, point 5 of the reasons; T 1708/06, point 6 of the reasons; T 469/03, point 4.2 of the reasons, none published in OJ EPO).

In the present case, claim 1 of the patent-in-suit requires a treatment in a human being and a dose of 0.1 to 30 micrograms of 13,14-dihydro-17-phenyl-18,19,20-trinor-PGF2alpha-isopropyl ester in 10 to 50 microlitres of the composition. These technical features are not required by any claim of EP0364417B. It follows that due to these technical distinguishing features the subject-matter of claim 1 of the patent-in-suit is not the same as that of claim 14 of EP0364417B.

Since EP0364417B and the patent in suit claim different subject-matter, the question of double patenting cannot arise.

Respondent I nevertheless referred to the headnote of T 307/03 (loc. cit.) which stipulates that a double patenting objection can also be raised where subject-matter of the granted claim is encompassed by the subject-matter of the claim later put forward.

The Board, however, sees no reason to depart from the mandatory requirement of "same subject-matter" invoked in the decisions G 1/05 and G 1/06 and in the established case law in relation with double patenting to claims on the mere ground that the subject-matter of the claim later put forward is already encompassed in a granted claim.

This argument of the Respondent I must thus be rejected.

Auxiliary request

9. Since the main request is considered to be allowable, it is not necessary to decide on the lower-ranking auxiliary request.